Content:

• What is important to know before installing a window sill with your own hands?
• Preparing to install a PVC window sill
• Video tutorial. DIY PVC window sill installation

Photo 1 - Plastic window sill photo

Practical, attractive and inexpensive plastic window sills are most often installed together with the same windows, although other design solutions are possible. Installation of window sills does not require special skills, but you need to follow the technology exactly and perform all actions carefully.

List of materials needed for installing a PVC window sill

What you need to know for a successful window sill installation

Before starting any work, you need to carefully study the accompanying documents for all materials and tools used, if you have not used them before. This fully applies to the installation of a plastic window sill.

For example, it is very important to know at what temperature you can work with polyurethane foam. This information is on the product label. When choosing this material, you should give preference to products with the lowest coefficient of expansion, which will prevent the window sill from rising. The ideal option is to use a spray foam gun. In this case, as a rule, professional material is used, which does not expand significantly.

If you are going to install a window sill in a window over 3 meters long, you will have to use additional parts that need to be carefully adjusted and glued, or special fillers for the joints.

Preparing to install a window sill

In order for the window sill to serve for a long time, it is important to correctly determine its dimensions. The width is calculated taking into account the following components:

Window sill width :

• Desired distance from the inner surface of the wall. Experts do not recommend making it more than 15 cm, because it can become a hindrance. It is also important to consider the location of heating devices. A window sill that is too wide can cause condensation to form on the side slopes and glass surfaces.
• Another 2 cm is added for the entrance of the window sill under the window.

To determine the length you need to measure the window opening using a tape measure and add another 10 cm to this value. This is necessary so that the cut edges of the window sill are not visible.

Important!

After taking all the measurements, check them again. It’s better to stick to the rule: measure seven times, cut once. In this way, you will be able to avoid annoying mistakes, which are quite difficult and sometimes impossible to correct.

All that remains is to cut off all the excess and you can begin installation.

Video installation of a PVC window sill. Main stages

First you need to clean the surface of the window opening from debris and dust. This must be done carefully so that subsequent foaming is successful. The next step is to try on a window sill that has already been prepared to size. If necessary, it is trimmed in the right places.

Photo 3 - DIY PVC window sill installation

Next step- installation of a window sill. To do this, it is inserted into a special support profile located under the window frame by 2 cm. Using a level, the surface of the window sill is set and wooden supports are placed, which are necessary to ensure the design rigidity during operation of the window sill.

The window sill canvas is installed with a slight slope directed into the room. This is necessary so that when condensation forms or watering flowers, excess moisture does not stagnate, but rolls off the windowsill.

Photo 4 - Do-it-yourself PVC window sill installation

The next stage is foaming. It is quite important and must be performed with special care. Before proceeding directly to the process itself, the surface of the window opening must be moistened. This technique allows for improved adhesion and a more uniform distribution of the polyurethane foam.

First, the inner surface of the window sill and the junction with the mounting profile are covered with foam. This allows you to avoid the appearance of such an unpleasant phenomenon as cold bridges.

Photo 5 - Do-it-yourself PVC window sill installation

After this operation, experts recommend installing a small weight on the windowsill, which is removed after the foam has completely hardened.

Polyurethane foam is afraid of ultraviolet radiation, so it should not be exposed to sunlight. Even a thin layer of plaster or other material can protect it.

All that remains is to install the plug, cutting off the required length from the workpiece, lubricate it with cosmofen, and press it to the ends of the window sill. And at the final stage, you need to remove the protective film and fill all the joints with silicone sealant, doing this very carefully.

Photo 6 - DIY PVC window sill installation

From the above, it becomes clear that even those who have a minimum of knowledge and skills in this area can cope with the installation of a plastic window sill. It is only important not to allow technology violations and not to rush.

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How to install window sills on plastic windows quickly and correctly

The internal window sill is an integral element of any window. It is officially believed that this part of the structure is necessary for additional insulation of the lower junction of the window frame and the wall and giving the window a finished look. In this article we will talk about what types of window sills there are and, since plastic windows occupy at least 50–70% of the market in our country, I will dwell in detail on how to properly install a window sill on plastic windows.

What types of window sills are there?

By and large, if the craftsmen installed the window frame efficiently and foamed the bottom gap well, this sector no longer needs special insulation. Therefore, owners are usually more interested in the question of how respectable this or that window sill will look, and, of course, the price of this pleasure.

Many inexperienced owners believe that since their windows are plastic, then all other fittings should also be mounted from PVC (polyvinyl chloride, popularly known as window plastic).

In fact, you can put any window sills here, the main thing is that they suit the design and you have enough money for them. Therefore, before installing a window sill on plastic windows, it would be a good idea to familiarize yourself with the main offers on the market:

• Naturally, the most popular material is the above-mentioned polyvinyl chloride. The hollow structure, reinforced with internal ribs, is considered quite warm and durable. It harmonizes almost perfectly with traditional white windows, and you can choose a window sill for laminated windows. Plus, the PVC plate costs quite reasonable money. Plastic is not afraid of moisture and, if the technology is not broken, then it will last as long as windows;

If the choice fell on PVC, you should not get carried away with saving, they are not expensive anyway. The fact is that plastic, like no other material, is exposed to sunlight. While the window sill is new, everything will be beautiful, but after six months the surface of the cheap plastic will change. At a minimum, it will turn yellow, and at maximum, it will crack and become deformed.

• Figuratively speaking, the older brother of polyvinyl chloride is a plastic window sill on an acrylic base. It costs about 3 times more, but the quality is much better. Whatever one may say, a PVC plate is afraid of elevated temperatures, unlike it, you can place hot pots on acrylic and even a cigarette butt forgotten on it will not cause harm to the surface. Acrylic plate is much stronger, its shiny glossy surface looks more respectable. The colors here are brighter and the palette is wider;

• The wooden window sill is rightfully considered the patriarch of this trend. In the budget sector, pine is usually used. The range of species in luxury window sills is much wider; it can be golden oak, teak and a dozen other exotic types of wood. But to be honest, I don’t understand people who put expensive natural wood on plastic windows. And in general, plastic does not harmonize well with wood, unless these windows are laminated to match a certain type of wood;

• Window sills made of laminated chipboard or MDF are a completely different matter.. In this case, these are the same slabs from which the countertops are made, which is actively used by designers. Chipboard will cost a little less, MDF will be more expensive. But MDF is more resistant to a humid environment and I always recommend using it. Since installing a window sill if the window is already standing is quite a feasible task for a home craftsman, people are now rushing en masse to replace the old plastic with new laminated MDF;

• A polished window sill made of natural stone certainly looks luxurious, but the prices for them are, frankly, exorbitant. Although if you look at it, they are not so good in operation. The fact is that natural stone is unpredictable; stains from coffee or red wine may remain on it; any slab always has a critical point, at which the slab will burst with a slight blow. Plus, the same granite can often and densely emit light radiation. Agree, it’s not very pleasant to install such a “gift” in your own home, and even at a great cost;

• Both in terms of cost and performance characteristics, it is much more profitable to install modern artificial stone. Firstly, in appearance it is often no different from natural. Secondly, it is more resistant to mechanical and chemical influences. The accusations of skeptics that artificial stone is less durable are only partly true. After all, for example, the warranty for porcelain stoneware starts from 50 – 70 years. To put it bluntly, these window sills are more likely to get boring than to fall apart.

No article is enough to talk about the manufacturers and prices of all existing types of window sills. But since even an amateur can install a plastic window sill correctly, I decided to stick with it. Plus, according to statistics, about 50% of the plastic window market is occupied by PVC window sills.

Below, to make it easier for you to navigate, I have compiled a small table that contains the most popular and reliable manufacturers of various window fittings with average prices for the window sills that interest us.

Window sill installation technique

The easiest way is to install or replace a window sill made of PVC and acrylic yourself. Installation instructions for MDF, chipboard and natural wood are not much more complicated. As for natural or artificial stone, it is better to entrust these materials to professionals, since not every master can install them.

Removing the old stove

Naturally, before replacing an old, outdated window sill with a new one, you must first dismantle it. Don't be alarmed, this is a simple matter, but a responsible one. After all, the more carefully you remove the slab, the less hassle there will be with preparing the base.

• If there is a wooden window sill, then to dismantle it you will need a hacksaw and a pry bar or a small crowbar. It’s not worth knocking out the board right away with a pry bar; you can seriously damage the slopes and then you’ll have to tinker with them as well. It is better to make 2 or 3 cuts and pull out the central part. In this case, on the sides you will have small pieces walled up in the slopes. These pieces need to be carefully knocked out with several blows from the side, at the end;

I am often asked whether it is possible to replace a hacksaw with a grinder? So, under no circumstances should you do this. Remember, perhaps the greatest number of injuries and injuries from an angle grinder occur precisely when trying to cut a tree with an angle grinder.

• But in the case of a reinforced concrete or stone slab, a grinder with a diamond blade will be exactly what you need. In this case, in addition to it, a heavy hammer or a small sledgehammer will also come in handy. First, several cuts are made with a grinder, if possible through. After this, take a hammer and knock out this entire “cut” with blows from bottom to top. Residues are cleaned using a pry bar;

• The fastening of a plastic window sill is considered one of the weakest. But before removing such a slab, you should first dismantle the ebb (outer window sill) and check whether our plastic is screwed on with self-tapping screws from the outside. If they are there, then naturally they will need to be unscrewed. If there are none, then all you have to do is carefully trim the mounting foam under the slab and try to pull out the window sill, simultaneously moving it down and towards you.

A few words about preparing the base

Whether you're replacing an old structure or working from a clean slate, before you install anything new, you need to prepare the foundation. In fact, all preparation consists of removing dust and debris, as well as filling large potholes, if any.

Some craftsmen advise making a level screed under the window sill, supposedly on its basis it will be easier to level the slab. I tried installing both with and without a screed, on a bare base.

I’ll tell you honestly, there’s nothing reprehensible in the screed, you can do this, but it’s a pity for the time spent on it. After all, by and large, there is no difference in whether you place wooden wedges on a flat base or on a curve. And if you plan to install it on alabaster or cement-sand mortar, arranging a level screed generally loses its meaning.

Let's start installation

Window sill installation always begins with fitting. Of course, ideally, it is better to install the window sill before arranging the slopes, while the walls are bare, but this only happens in new buildings.

Since we are talking about how to replace the old with the new, we will have to cut, or rather, knock out grooves in the side slopes. There is one interesting nuance here. The instructions recommend that before placing the window sill to the plastic window, make wide lateral allowances, approximately 5 - 7 cm from each edge.

That is, we need to make side grooves in the slopes 5–7 cm deep along the outer edge. It is believed that this is supposedly more elegant. If you need to cultivate 1 - 2 windows, then these approaches to the walls will not play a big role.

It’s a completely different matter when the task is to completely furnish all the windows in a fairly large private house, and funds are limited. In this case, an addition of 10 cm on each window will eventually result in a whole extra window sill.

Personally, I always recommend making side tolerances of no more than 20 - 30 mm. Believe me, this is quite enough to ensure a decent appearance. Moreover, most windows in residential buildings and apartments have curtains that will completely cover all these tolerances.

The side grooves themselves are knocked out to the tolerance depth, that is, to the distance at which the slab will go inside the slope.

In order to accurately mark and not grab excess, you need to take a square, attach it to the window frame and draw a horizontal line starting from the top cut of the groove under the window sill and ending with the outer cut of the slope. This will be the upper boundary of our groove.

The easiest way is to make cuts on the slopes with a grinder to the required depth, and then knock out the excess using a hammer drill or chisel with a hammer.

Plastic window sills can be installed in two ways, with or without fixation on the window frame. The only difference is that in the first version, the inner end of the window sill, the one that is adjacent to the window frame, is first rigidly fixed to this very frame. Further, the entire installation algorithm is completely identical.

When marking and trimming the window sill, it should be taken into account that it should not protrude beyond the cut of the wall by more than 5 - 7 cm. And under the frame itself the plane is immersed by a maximum of 1 - 2 cm.

Fixing it to the frame is extremely simple. In the place where the window sill will be adjacent to the frame, in increments of 300 - 400 mm, a series of through holes are made along the horizon. After which, the window sill is pressed against the frame and from the street side, screwed through these holes with long self-tapping screws. The self-tapping screws must enter the body of the slab at least 20 - 30 mm.

But it is not always possible to screw the slab to the frame with self-tapping screws. In this case, it is simply inserted under the frame. To enhance the thermal insulation, immediately before strengthening the slab, I apply a couple of strips of polyurethane foam to the installation site.

The installation of a plastic window sill itself looks something like this: first we insert the slab we cut out and see how it will lie in the future. There is no need to worry about horizontal curvature. After all, the slab is adjacent to the lower edge of the window frame, which is already aligned to the horizon.

But we need to slightly tilt the slab towards the inside of the room so that, if necessary, water does not accumulate, but flows freely from the window sill. As far as I have come across, different sources interpret the value of this angle differently. Personally, I tilt it around 5mm in width.

The inclined slab itself will be based on wooden wedges. These wedges are usually installed at a distance of about 300 mm from each other. Each of them is cut and adjusted personally and must fit tightly, without gaps.

As mentioned earlier, the plate sits in a groove under the window frame on mounting foam. Then it rests on the wedges we installed. But before you secure it completely, check again that it stands firmly, without distortions or play. It’s better to tinker with adjusting the wedges now than to constantly cover up the cracks later.

To increase the adhesion (adhesion) of the polyurethane foam to any surface, this very surface must be well moistened.

The slab is secured by filling the voids underneath it with foam. And don’t try to blow out too much foam, it won’t make things better, the extra will come out anyway.

As you know, polyurethane foam expands when it hardens, and if this feature is not taken into account in time, then your window sill may squeeze out in the middle. To prevent such an incident from happening, after filling the gaps with foam, you need to place a load of about 15 - 20 kg on the windowsill. It should stand for at least 10 - 12 hours.

At the last stage, the load is removed, the excess foam squeezed out from below is cut off, and the unflattering cracks on the sides of the slopes are filled with putty. Then all that remains is to admire your work.

Installation of wood and its derivatives

As I already mentioned, installing window sills made of natural wood, MDF or chipboard is not a little more complicated than installing plastic. Here, in exactly the same way, you need to knock out the grooves in the slopes after marking.

The window sill itself, if the frame design allows, it is advisable to fix it on the frame or on a base profile, which is placed under the frame. As in the case of plastic, this is done using self-tapping screws through through holes.

But in this case there is one small nuance: there is such an interesting physical quantity as the coefficient of thermal expansion of the material. So, when we put a plastic window sill on a plastic window there is nothing to be afraid of, because this coefficient is the same.

But in the case of joining different materials, as a result of a mismatch in thermal and moisture expansion, gaps and cracks may appear over time. Therefore, we will need to glue a so-called damper tape to the end of the slab, which is designed to compensate for these vibrations.

Naturally, this tape is glued or attached to brackets only in places of direct contact with the body of the slopes and the window frame. Traditionally, the material for such tape is felt impregnated with an antiseptic. Although now some craftsmen use penofol (foamed polyethylene).

Wood, chipboard or MDF are heavier than plastic, so I personally prefer to use gypsum mortar instead of polyurethane foam, it’s more reliable. Instead of gypsum, you can just as successfully install the slab on a cement-sand mortar diluted in a ratio of 1:3.

In this case, the instructions will look something like this. We knock out grooves in the slopes, try on the slab and grind the required number of wooden wedges under it. After this, apply the solution to the base. The layer of solution should cover the wedges by 5 - 10 mm.

Further along the line where it joins the frame, we apply a couple of strips of polyurethane foam. We insert the window sill with the damper tape and press it until it rests against the wedges. We remove the excess squeezed out mortar and putty the cracks on the slopes at the junction with the slab.

If everything is done correctly, the window sill will stand firmly. But some masters prefer to play it safe. They drive a long nail into wooden wedges from below in such a way that it goes right through and looks out from above by 10 - 15 mm. The wooden wedge itself is fixed to the base with an anchor.

As a result, when you finally insert the slab, it fits onto the nails protruding from the wedges and is firmly attached. The method is worthy of attention.

The only downside here is that before installation you need to carefully measure and check everything several times. Otherwise, in case of an error, almost everything will have to be done again, because the nails will no longer allow you to move or adjust the slab.

Conclusion

Now you know how to install a window sill on plastic windows. The photos and videos in this article provide additional information on this topic. If you have any questions, leave them in the comments and let's talk.

Reading time: 8 min.

A window sill is a part of a window opening that performs a practical and decorative function. Before attaching the window sill to the plane of the plastic window, it is necessary to perform a number of preparatory measures. This work is performed by specialists when installing a window, but if you have the appropriate knowledge and skills, the task can be completed independently. To do this, you need to consider several important aspects and features.

Types of window sills

The window sill retains heat and prevents cold air from entering the room from outside. On the practical side, this element is a place to place indoor plants, photographs, household items, and products with a large surface area can even become a place for relaxing and reading books.

There are several types of window sills, each of which differs in characteristics, appearance and service life. Mono-material window sills include products made from marble, wood, stone and granite, while composite window sills include products made from MDF, polyvinyl chloride and chipboard.

Plastic

A PVC window sill is usually rectangular in shape, usually in a white shade, although there are options in other colors. It is possible to make a window sill in the shape of a semicircle, but it is impossible to find suitable plugs.

The maximum width is 800 mm, and the minimum is 20 mm. The length can be from 1.5 to 6 meters. In production, before sending it to the recipient, it is reduced to the required value. The advantages of such models include:

• normal shock resistance even at sub-zero temperatures;
• high thermal insulation qualities;
• resistance to moisture and sunlight;
• strength due to stiffening ribs;
• resistance to thermal effects, mechanical stress, scratches;
• ease of installation.

The main coating is melamine. The substance improves technical characteristics and protects against negative environmental conditions. A budget covering option is PVC film. The material does not burn, shows resistance to ultraviolet waves and does not deform at temperatures up to +60 degrees. The options for using window sills have expanded significantly thanks to an acrylic coating that imitates valuable wood and other natural surfaces.

Wood

Natural wood products are made from various species, including oak, chestnut, pine, beech, and ash. Proper processing of the material makes the window sill protected from moisture and resistant to other negative factors. The absence of harmful components in the composition and noble appearance are the main advantages of such models. In terms of cost, the cheapest option would be pine; the premium price segment includes cherry, oak, and ash. Additionally, the surface is coated with a protective varnish.

Window sill boards made of wood-fiber and particle boards (chipboard, MDF) are popular. They are made from moisture-resistant materials, do not require special care and are easy to clean. They are covered with films or veneer to imitate valuable types of wood, stone, in particular marble. The cost of these models is lower than their natural counterparts, but in appearance they are almost identical. An additional advantage of the wooden analogue is its long service life.

Made from artificial stone

The presence of natural materials in the interior of a home is a sign of the wealth and wealth of the owners. One such material is stone. Its price allows us to classify it as a premium class. It should be noted that it is difficult to install a stone window sill. An excellent alternative is artificial stone; it is relatively lightweight and easy to install.

Manufacturers produce various models with a rich palette of shades, with all kinds of inclusions and patterns. A white stone window panel is suitable for a classic interior. Such a window sill contributes to the respectability and aesthetics of the room. The advantages of the material include high strength, resistance to negative factors and a long service life. If defects appear, the product can be easily restored. Modern equipment allows us to produce window sills of any shape.

The disadvantages include the cost, which is significantly higher than that of models made from MFD or chipboard. Due to the use of detergents with abrasive elements, scratches and small cracks remain on the surface. These problems can be avoided by following simple care rules.

Methods for installing window sills

Installation is included in the price of a plastic window and is carried out by experienced specialists. They have a rich list of tools and the necessary skills, but if desired, this procedure can be performed independently. To do this, you should choose an installation method, which depends on the characteristics of the room and the configuration of the window system. In the past, a special solution was used to attach a plastic window sill, but this technology has been replaced by more advanced methods.

Mounting on polyurethane foam

Polyurethane foam can absorb moisture, which leads to its destruction. Before installing a window sill, it is necessary to consider a system of hydro- and thermal insulation. Corrugated cardboard or polyethylene foam is suitable for this. On the window side, a sealant is applied to the end of the strip, which contains substances against fungus and mold. The product is fixed at a slight angle and supported by wooden blocks 40x50 mm.

The bars are positioned sideways, occupying the space between the auxiliary board and the slope. Then wedges are driven under the edges of the bars. If the window sill is made of wood or MDF, then polyethylene foam pads are placed at the points of contact with the wall. After plastering the slopes, the excess parts are cut off. All cavities under the window sill are sealed with polyurethane foam. When the substance hardens, beacons, spacers and other additional devices are removed.

Using fasteners or mounting strips

Fastening a window sill using this method is characterized by a long implementation time, but a high level of reliability. To perform the work you must have some knowledge and skills. First of all, the difficulty arises with counting the clamps and determining their correct location.

Attaching a window sill to a plastic window in a regular room and on a loggia or balcony is practically no different. In an apartment on a high floor, you need to use additional thermal insulation materials that are resistant to strong gusts of wind.

Using Brackets

The bracket is a spring bracket for reliable fastening of window sills. The element is made of polymer materials, the possibility of bending guarantees tight fastening. The plate is attached with a self-tapping screw, which fits into the hole made.

Installation sequence for window sill anchors:

1. The bracket is secured to the stand profile with a self-tapping screw.
2. The number of plates is determined by the geometric features of the product. On average, 5-7 pieces per 1300 mm length are enough. If the length is greater, then the structure must be reinforced with additional brackets.
3. The space under the window sill is filled with a uniform layer of polyurethane foam.
4. The window sill is brought into place and snaps into place after light pressure.
5. The level is adjusted.

Thanks to the use of anchor plates, the likelihood of errors when performing work is minimized. Plus, attaching a PVC window sill with brackets takes a little time and takes a small amount of effort and money.

Step-by-step installation instructions

Depending on the chosen installation method, you need to prepare a list of tools, perform a number of preparatory measures, make markings and ensure good thermal insulation. The quality of the work performed determines the further result and speed of installation. Attaching any window sill to a plastic window is divided into several stages, each of which is of great importance and also affects the quality and durability of the window sill panel.

Required Tools

To replace or install a new window sill, you need to prepare a set of materials and tools. The list includes:

• silicone sealant;
• perforator;
• polyurethane foam and hand gun;
• end caps for connecting panels;
• grinder or jigsaw;
• roulette;
• pencil;
• building level;
• cement mortar.

Many home craftsmen have these devices, so no special costs are required. Plugs and additional elements must be included in the kit. If necessary, they can be purchased at a hardware store.

Preparing the base

Before attaching the window sill to a plastic window, if there is an old strip, it must be removed. Dismantling the old window sill is carried out using a pry bar and a hammer. First of all, the lower area of ​​the window opening is cleared of dust and construction debris. Then the niche geometry is adjusted to fit the new panel. Excess parts are removed with a hammer drill, and the surface is increased to the required height with cement mortar. This method is suitable for correcting side edges.

A gap of 20 mm must be left between the base and the new window sill to fix the product with polyurethane foam. At the junction with the window frame, a thick layer of silicone sealant is applied, thereby eliminating the voids through which cold air penetrates from the street.

The plastic window sill on the balcony is long and small in width, which complicates the installation process. In some cases, the help of a second person is required.

Marking and trimming the window sill

After preparing the base, the niche is measured, and, in accordance with the obtained values, the window sill is cut out. A grinder or an electric jigsaw will help you cope with this task. Then the slab is mounted in the designated place and wedged with wedges made of wood or plastic. The horizontality of the surface is controlled by the building level.

Installation work

To correct the position, wedges of different thicknesses are used. During the installation process, it should be remembered that the window sill should have a slight slope towards the room - about 2 degrees. This is necessary to remove water from flower pots and condensation onto the floor, and not into the window cavity. The gap is filled with polyurethane foam. To securely fasten the plate from above, press it evenly with a load, for example, four eggplants with water, placing them at the same distance from each other. The product must be left for 2-3 days. This is enough to harden the foam.

Excess pieces of foam are cut off. A stationery knife does this job well. At first, the window sill should not be heavily loaded, so as not to disturb the alignment on two planes and not to deform the product. At this point, attaching the PVC window sill to the window frame on the balcony or indoors does not stop, since you need to install plugs and “blow out” the cracks with foam.

Installing plugs and sealing cracks on slopes and under window sills

Small gaps and even cracks form at the junction of the window sill and the slope. It is necessary to deal with them only after installing all the component elements of the window structure. Gaps are removed with silicone sealant, the substance is applied in a thin layer. Masking tape should be used to cover surfaces that should not come into contact with silicone.

The side edges of the window sill are closed with end caps. They are sold at any hardware store, but must be included in the kit. The protective film is removed from the surface of the panel.

Qualified workers spend several hours installing a window with a window sill; an inexperienced worker takes much longer. At the same time, compliance with certain rules speeds up the process and improves the quality of the final result. Experts give some important advice:

• It is necessary to install a window sill with a protrusion from the slope line of at least 6 cm. If this is not done, the air circulation will be disrupted, which will cause constant fogging of the windows.
• Polyurethane foam adheres much better to a moistened surface.
• Measuring and cutting the slab are the most important steps during installation, so you need to approach them carefully and responsibly.
• If contamination appears on the surface, and tooth powder, vinegar, soda, soap and chalk are ineffective, then use chemical cleaners. Such products can quickly remove dirt from plastic, but aggressive substances can damage its structure. Special solutions for PVC windows are available for sale. Despite their gentle action, they cope with old stains without damaging the structure of the panel.

Working with electric tools contains many dangers. Before using it, you need to make sure that the wiring is intact and that there is no moisture in the open parts of the hammer drill or grinder. It is imperative to use eye protection and minimize the area of ​​exposed skin. A long-sleeved work uniform and gloves are ideal.

How to seal foam under a windowsill

Foam not only degrades the aesthetic qualities of the window system, but also requires additional protection. The material shows excellent thermal insulation properties, but is destroyed by moisture. You can seal the foam using two methods:

1. The trimmed foam is covered with tile adhesive. Before painting the walls, the area treated with glue must be sealed with putty. If there is wallpaper on the walls, it is better to treat the surface with an acrylic-type primer.
2. The second method involves the use of vapor-permeable tape. The product must be cut according to the required dimensions and secured in free space. A decorative cover made of wood, aluminum or PVC is mounted on top of the system.

Each technology has a number of undoubted advantages, but their combination will give the maximum result. The cost of consumables is insignificant, so you can easily use two methods at the same time.

Installing a window sill is a complex process that requires a set of tools, supplies and special skills. Many home craftsmen fix the window sill correctly on their own, and the quality of the result is excellent.

Modern construction trends involve the use of the most ergonomic materials. The requirements of the average buyer are as follows: the material must be light, durable and inexpensive. Previously, wood was used almost everywhere, but now it is considered a premium material. It was replaced by plastic - it is more durable, cheaper and has almost limitless decorating properties.
Most often, plastic is used in metal-plastic windows, which are now installed almost everywhere. In addition to them, it is necessary to install a window sill and slopes. Each element plays an important role in everyday life, and their selection and installation must be approached with particular care.

Installation technology

More often than not, it turns out that the main technical purpose of these products is completely forgotten. They are usually used as a flower stand; especially large and durable versions can be designed as a continuation and extension of the workspace or in the office, you can even place a comfortable sofa there for reading books.

In addition to all this, the window sills, with their protrusion, trap the warm air rising from the radiators at a low level, which allows you to warm up the living space much better.

Immediately after installation, you need to let it sit for a couple of days, after which the installation of the window sill begins. You need to prepare the tools:

• sharp construction knife;
• hacksaw for metal;
• sandpaper;
• hammer and chisel (if available, an impact drill or hammer drill);
• wooden or plastic pads for leveling the surface;
• building level.

• According to the established rule, the window sill must extend into the side walls by at least 3 cm. Using a tool, it is necessary to make special recesses at the level where the surface will be located.
• If a new one is being installed, the window sill can be ordered from the same manufacturer. If they are installed separately after a long period of time, or it was decided to replace the old version with a new one, then it will have to be found in specialized stores or made to order. To measure the product, it is best to invite a specialist - he will accurately set the parameters of the product and will be responsible for this.

• It is important to make sure that after installing the metal-plastic window, the putty, mounting solution and foam are completely dry. After this, you can begin preparing the working surface - it should be clean, free of foreign protrusions, dust and construction debris, and as smooth as possible. All hard protrusions are carefully knocked down with a chisel or drill, dust is removed with a broom or construction vacuum cleaner, and polyurethane foam is removed with a sharp knife.
• Even if the finished window sill was made exactly according to the specified parameters, situations may arise when in some place it does not fit as it should. To solve this problem, sandpaper and a hacksaw are useful - in the right places, the finished blade is adjusted to the position being installed. If it is possible to start fitting the window sill from the side of the wall, it is better to start there, using a hammer and chisel or a strong screwdriver. As a result, the window sill should confidently fit into its intended place, not hang out in the grooves of the side walls, but also not rub in too much.

• You need to spray the prepared work surface with plain water using a broom or mechanical sprayer - the foam will stick much easier to the moisture, which will make working with it much easier. This stage is very important, because It is the polyurethane foam that is the main fixing material.
• There are three holes for installation in place - two side grooves and a recess in the window itself. The last hole should accept the window sill as clearly as possible - the unsuccessful gap will be visible during the operation of the living space.
• The most important part of installation is setting the surface according to the level. To measure indicators, a mounting level is used. To adjust the angles of inclination, plastic or wooden plates are placed under it. The slope should be set slightly towards the room so that moisture does not linger in the groove between the horizontal surface and the window and mold and dampness do not grow there.

• After the correct level has been set, you need to press down the new surface with something heavy; bricks wrapped in rags are ideal. They will hold the window sill when the polyurethane foam swells.
• All empty space underneath is carefully and carefully filled with polyurethane foam. The structures are allowed to stand for at least a day.
• After the foam has dried, its remains are cut off with a knife - and the window sill is ready for use.

Slopes

An ideal complement to the window sill would be slopes made of a similar material.
This option has a number of undeniable advantages:

• relatively cheap materials;
• simple installation that does not require the help of specialists;
• reliability and wear resistance;
• ease of care.

The procedure for installing slopes

1. The slopes consist of the following elements - sandwich panel, F-profile, wooden planks and self-tapping screws. All the irregularities of the unprepared wall are hidden under the panel.
2. Wooden strips are placed on the edges of the slopes to cover the entire height and width of the window opening. An F-profile is screwed on top of them with self-tapping screws, which has special grooves for installing a plastic panel.
3. The profile and plastic panel are refined using metal scissors. The main task is to prevent unsightly gaps.
4. You can put mineral wool on the wall directly under the panel or fill the space with foam plastic - this will eliminate drafts and significantly insulate the walls.

Conclusion

Plastic windows are perfectly equipped with ergonomic window sills and slopes made of similar material. Their installation does not require the involvement of specialists; they will last for decades. Maintenance is very simple and immediately covers all installation costs.

Detailed video instructions can be viewed on the video.

The final stage of window installation is the installation of the window sill. This process is ridiculously simple, however, it is quite easy to make a mistake. In our instructions, we will show with examples how to properly organize the connection of the window sill to the window frame, carry out the sealing and prevent freezing of the lower zone.

Selecting the type and size of window sill

Despite the fact that the products of most manufacturers of additional components for PVC windows are well unified, there are several types of plastic window sills. However, perhaps you would prefer window sills made of natural wood, artificial stone or veneered countertops? We will also consider such options, but remember that often the choice of a particular type of product is dictated not by whim, but by obvious necessity.

For example, consider two types of plastic window sills - with and without an edge at the back. On the one hand, a window sill without an edge allows you to freely vary its depth and even tolerates oblique cuts, which can correct flaws in window installation. However, in this case, it may be necessary to mount it from the outside through a stand profile, but not all windows have it and it is not always convenient to dismantle the external ebb for fastening. Otherwise, plastic window sills are almost identical except for one feature - thickness. The larger it is, the correspondingly higher the strength of the window sill and its greater protrusion above the plane of the wall is allowed.

Plastic window sills are usually sufficient to meet most needs, but it is worth considering the benefits of other materials. Basically, laminated chipboards and artificial stone slabs are used where you need to add a special twist to the color. “Non-plastic” window sills have no other advantages - they are afraid of moisture, dirt and ultraviolet radiation. However, one nuance still remains: if it is necessary to arrange a solid window sill for several windows, as is the case when installing glazing for a bay window, a continuous curvilinear contour can only be created with the help of a window sill-tabletop.

As for the sizes, everything is simple and obvious with them. The length of the profile must be at least 6 cm greater than the distance between the slopes at the widest part. The depth should provide a protrusion above the wall plane of at least 30 mm, and if there is a radiator under the window, “cover” it with a margin of 5-10 mm.

Preparing the installation site

The opening must be prepared in a certain way for the installation of a window sill, and for each individual installation method, the preparation will have some differences. Let's start with what is the same in all options: we apply a square to the vertical posts, aligning the edge along the lower edge of the frame profile, and draw two horizontal lines on the slopes that limit the hem. Along the lines, you need to make cuts using an angle grinder and a diamond disc to a depth of about 10-15 mm; if there is a plaster corner at the corner of the slope, it should be cut completely. Next, use a chisel or an old chisel to select pockets with a depth of about 30-50 mm in the slopes. More is possible, but it should not be less than 30 mm, otherwise the connection of the side plugs with the angle of repose will be incorrect. If the slopes will be covered with panels, the protrusion of the window sill beyond the slope should correspond to the width of the closing corner profile.

If a heavy tabletop is installed instead of a light plastic profile, you need to prepare the lower plane of the window opening. First, a plaster beacon is installed under the side of the frame, close to the stand profile, on the tubercles of cement mortar. The distance between the edge of the lighthouse and the window frame must exactly correspond to the thickness of the window sill-tabletop. Using cement mortar, a smooth horizontal edge of the opening is drawn along the lighthouse, on which the window sill will rest; it is advisable to strengthen the inner corner with a plaster corner.

Don’t be surprised, but it also happens that a window is installed without a support profile. If in this case a window sill with a thickness of 18 mm or more is installed without a trailing edge, it is necessary to increase the thickness of the bottom foam seam to at least half the thickness of the window sill profile used. Also, in the lower part of the slope, a series of vertical notches are made in the wall, 30 mm wide, 20 mm deep and about 120-150 mm high. Notches must be made in increments not exceeding 80 cm and at least two pieces per window sill.

Window sill fastening

Unlike common practice, the window sill does not necessarily need to be secured through the frame profile with self-tapping screws. In some cases, this will only cause harm: metal rods serve as excellent cold bridges.

The most correct installation scheme is ridiculously simple: the window sill rests on the stand profile, then incompressible pads are installed under it, for example, mounting wedges, retreating 2/3 of the total depth from the front edge. A small protrusion of the frame above the stand profile allows you to adjust the projection of the window sill above the plane of the wall if the window frame is turned out for some reason. With this installation method, the mounting foam firmly connects the window sill with the opening, while tightly filling the entire space from below.

The window sill without a support profile is fastened using the rear side, which fits tightly into the installation groove in the lower part of the frame. It is only important to clear the foam seam a little and cut off the edge on the sides, otherwise you will have to cut the slopes deeper. Window sills of increased thickness without an installation side have a longitudinal dovetail groove on the back. Light mounting plates are inserted into this groove, which are used for preliminary alignment of windows. To correctly install the window sill, supports are paved under its rear part with wedges, then the window sill is laid in place, the plates are bent and secured deep into the notches in the wall, which ensures that the end of the profile is tightly pressed to the frame.

Sealing the lower zone

The main trick when installing a window sill is to correctly form the foam seam underneath it. The only exceptions are window sills-tabletops, which are attached to the prepared opening plane using liquid nails.

In general, for correct installation a number of conditions must be met:

1. The lower shelf of the opening was cut down with a slight bevel towards itself, dust-free and moistened with water.
2. Incompressible pads are placed under the window sill; when you press on the front edge of the profile, it is pressed tightly against the bottom of the frame and maintains a strictly horizontal position.
3. From above, the window sill is pre-loaded with a weight of about 20 kg per meter, the oppression is distributed along the entire length using a board.
4. On the sides, the upper plane of the window sill rests against the notches on the slopes.

Then everything happens extremely simply. The entire space between the window sill and the shelf of the opening is filled with polyurethane foam of the appropriate climate regime, with the exception of areas located behind the slope line. You need to blow out the foam under low pressure, using an extension tube to fill the narrowest areas in the back near the frame. After blowing the foam, the window sill should remain loaded until the polymerization of the foam is completed - about 1-1.5 hours.

Sealing cracks in walls and slopes

After the foam has completely hardened, its excess must be cut off. If the foam has been squeezed into the area beyond the slope line, it must be dug out to a depth of at least 20 mm. Under the window, the foam is removed with a chisel or scraper to a depth of about 10 mm. All formed cavities are moistened with a strengthening primer from a spray bottle.

The voids must be filled with cement mortar, to which alabaster is added in small portions to speed up setting. After the solution has dried, the sealing areas are ground to the general plane of the wall using an abrasive mesh. The gaps between the window sill and the slope must be sealed; this is the main path for cold air to enter. If you subsequently plan to finish the slope with plastic panels, sealing the cracks does not need to be leveled; in this case, sealing can be carried out using polyurethane foam.

If the trim was done correctly along a single line without gaps, you need to complete the finishing on the slopes, paint them, and then fill the gaps with white acrylic sealant. If the edge of the hem is uneven, the sealant is pumped deep into the gap, not reaching the surface by 5-7 mm. The remaining gap is sealed with finishing putty.

How to prevent condensation from forming

A typical consequence of installation errors is the formation of condensation. It can appear both on the windowsill itself and on the glass. Each case has its own reason.

Hypothermia of the window sill occurs due to a violation of the foam seam in the lower zone. The best thing to do in this case is to disassemble the ebb from the outside and scrape out the remaining foam from under the frame. After cleaning, the bottom seam is filled with foam again.

Condensation on glass appears mainly when using single-chamber double-glazed windows with high thermal conductivity. Such windows require a continuous thermal curtain from radiators during the cold season. If the window sill protrudes too much, it will block the flow of hot air and the glass will not warm up properly. The problem can be solved by inserting 2-3 convection sleeves into the window sill, which are also used for pulling cables through the walls of cabinet furniture.