Installing a plastic window sill with your hands

Installing a plastic window sill Table of contents:

  • 1 Choose the right
  • 2 Tool
  • 3 Foundation preparation
  • 4 Installation
  • 5 If there is skew
  • 6 videos

You can well get a window sill separately from plastic windows, because it can, for example, break, or you first wanted leave the old wooden windowsill, but then changed their minds. we tell you how to install a plastic window sill do it yourself.

Choose the right one

If you opted for a PVC window sill, most likely all positive and negative were evaluated side. The advantages are:

  • Durability. Plastic itself is very durable. life time. It is not affected by water or other corrosive non-aggressive fluids.
  • Relative ease of installation. Compared to products from other materials less risk of doing something wrong during installation.
  • Reasonable cost. Window sills made of artificial or natural stone have a cost that is significantly higher.
  • Light weight.
  • Ease of processing.
  • Additional thermal insulation.
  • Easy to clean. Almost any non-abrasive detergent facilities.

Here are some cons:

  • Instability to high temperatures (in the majority cases).
  • Inability to recover from damage. If wooden ones, for example, can be puttied, cleaned and painted, then here such a number will not work.
  • If the surface of the product is rough, there with time dirt accumulates, which is not so easy to wash.

Window sills can be purchased both with installed windows, and after. Their installation is carried out both on the balcony and in wooden house. In this case, you should pay attention to:

PVC window sill of dark colorPVC window sill dark colors

  • Color. It does not have to be white, as many are used to. There are various color options that mimic marble or wood. Of course, it is better to dwell on what will be in tone go to the mounted windows.
  • Manufacturer. Brand influences quality in many ways. For instance, some plants apply a coating on the surface that can be resistant both to temperature and to abrasive substances.
  • PVC window sill structureSill PVC structure Design. Be sure to look at the end face of the cut. More than the thickness of the stiffeners, the better, the greater the load stand the product.
  • Warranty. With the right installation work, you can rely on the manufacturer to be responsible for his brainchild.


In order for the installation to go like clockwork, we need following tools:

  • hammer;
  • roulette;
  • level or laser level;
  • building corner;
  • polyurethane foam and gun;
  • Bulgarian;
  • chisel;
  • plastic linings or from other material;
  • acrylic or silicone sealant;
  • side plugs.

Foam can be of varying degrees of expansion. Pick her stands to fit your needs. But better not take the one that is completely will not expand, because she will not be able to compensate for some cracks, and they may remain after installation.

Foundation preparation

Foundation preparation

This step can take most of the time, but actually he is the most important in the whole process.

We look how the window is installed. It is important to evaluate if there are any deviations from the horizontal plane. For this we apply level or on the lower edge of the frame we start the projection from the laser level. In the future, the window sill will be exhibited precisely by him, which can also lead to distortion. If there are small deviations, it’s not scary, it will be described further in what way they can be compensated.

Measure the width of the window opening. It is important to remember that the plane supports should be 1 cm from each end recessed into slopes, and the protruding part on the sides should go beyond the opening by 3 cm or more.

We make grooves in the slopes where the ends of the windowsill will go. Landmark in this respect the edge of the frame will serve. Pay attention to the edge stands on which the window stands, namely the lower edge of the frame.

In order to do everything right, you can use several ways. Using a laser plane builder a horizontal line is projected onto the opening. From this line on the window measurement is made to the edge, the value is fixed. Further from the same lines laid the same distance, but already on the slope. If there is no level, then you can use water or ordinary level, which is placed close to the bottom line of the frame, aligned horizontally with a bubble indicator and a mark is made.

A straight line is drawn that connects our mark and the edge. frames.

Most likely, at the corners of the slopes is a metal corner. His In no case should you try to knock down with a chisel and hammer, so you can damage it completely. Better for this use a grinder. Just two small cross notch to its width. An incision is also made on the applied lines.

Slope preparationSlope preparation

With a chisel or other suitable tool and hammer 1.5–2 cm indentations are knocked out.

Next, you need to evaluate the surface on which installation is carried out. You need to pay attention not only to how uneven it is, but also how far away it is to the bottom of the window. Ideally, it should not exceed 4 cm. This is due to the fact that it is with such a thickness that the foam is the best polymerizes in a way that makes it sufficiently dense and durable. If the layer size is large, then inside can voids form, which reduces the bearing capacity, as well as can cause drafts.

In the event that the size exceeds 4 cm, it is necessary to reduce the gap. This can be done using improvised means. For instance, You can build a small formwork from the rule and fill the solution. IN in this case it will be easier to deduce the required level. If installation carried out while there are still leftovers inside the room brick or foam block from peremenok, then you can lay out of them base, and seal all the cracks with a solution or glue. After that you need give at least a day, so that everything would stand and grasp.

In the case when the level of the base will rise at the help of the foam block, it must be soaked briefly in water. Due to its porosity, it absorbs moisture well, and if too he will take it a lot from the solution on which it will be put, there will be no setting. Wetting saturates the foam block with moisture, therefore setting will occur as well as possible.

The site can be considered finished, now you need to be right transfer all measurements to the canvas and take into account some nuances.

Installation work

The first step is cleaning. It is better to produce it when using a building vacuum cleaner, because brushes and brushes are not capable remove all dust.

Moisture is required for good adhesion of the foam to other materials. Therefore, it is recommended to moisten the surface with water. But you can go further and kill two birds with one stone. Do not use water, but primer. This way you can remove dust and provide the necessary hydration. You can apply it with brushes, but it is more convenient to do this with a hand spray. If you will be use the latter, then cover something with windows or immediately Wipe them. If the impregnation is allowed to dry, then then it will have to shoot with the consequences.

Better use a primer.Better to use primer

The window sill is marked. Its total width will be make up the width of the opening plus 10 cm (this overlap is necessary to provide 5 cm on each “ear”). Depth will be equal to distance from the window stand to the middle of the heater, if it located under the window. It’s better not to close it completely. If done this, then warm air will not flow to the glasses, and they will fog up, which will cause condensation to build up and overgrow mold and mildew. If there is no battery and radiator, then you can fly 5 cm. In some cases, at the request of the customer an even larger protrusion is made. Space may be used as a continuation of the desktop or something else. In such case, it is necessary to install metal supports corners. Their base is recessed into the plaster. Windowsill length it is adjusted taking into account the fact that by 1 cm the edges will be recessed into the wall.

Features of installing PVC windowsillFeatures PVC window sill installation

Using a hacksaw or electric jigsaw cropping is in progress.

Wooden wedges for a plastic windowWooden wedges for plastic window

Next, you need to prepare the supports that will lie plane. Often use special plastic plates, but they may not give the necessary rigidity. Instead, you can apply parts of the trimmed window sill. They should be located every 40‒50 cm. They are exhibited using a building level or using the level (when using the latter, it is projected the line and from it at two ends measurements are taken to the props, the distance should be the same). Their height should be such so that the window sill end-to-end went under the lower part of the frame and rested on setting bar. In order not to shift them in the process, You can fix them with self-tapping screws. If the playground is out gas block, then you can simply screw through it with screws, in case with a brick you have to use a punch dowels.

PVC window sill installation diagramInstallation diagram window sill pvc

You can go the other way and install props not across, and along the windowsill. They can be made from stucco beacons. In this case, there will be more emphasis, which will definitely exclude deflections and creases.

Alignment of the windowsillAlignment windowsill

Sealing with a gun and foam slots that may be under the window. Especially carefully need to relate to the corners. There are times that everything is installed beautiful, and from the bottom it blows a draft, which is an indicator inattention.


Plugs are mounted on the windowsill, and he tries on his a place. If there are no gaps between it and the window, then you can continue mounting. In the case when the gap is large enough, it is necessary raise the supports, with its minimum values ​​you can rely on foam to compensate for the gap. Until the repair is completed completely, the film does not need to be removed, it will be enough to lift it in those places that will hide in the wall and under the window.

View of the windowsill from belowWindow sill bottom view

If the supports were mounted along, then the main layer of foam must be applied before the window sill is in place. If across, then blowing can be done in several stages. Before installation – the part that is closer to the window. Then go through the middle lines, and then around the edge.

Fill the gap with mounting foamFill the gap polyurethane foam

For a day, the plane must be crushed using the load. For this can use books, eggplant with water, dumbbells (but under it is desirable to make them lining of durable material), etc.

Fixing a plastic window sillFixation plastic window sill

After polymerization and drying of the foam, its excess is cut off. Moreover, under the windowsill it needs to be cut flush about 1 see, so that you can calmly putty this space and The applied material had a sufficient layer.

We close the cement putty seam under the windowsillClose up cement putty seam under the windowsill

If there is a skew

The solution will be a little trick installation. Most often it is remains invisible to others, especially if the width of the product more than 25 cm. For this we need screws or some other material with which you can make adjustable beacons. They are mounted in two lines. First must be practically close to the window, and its level should be repeat the window tilt accurately. The second is set closer to to the edge. It needs to be aligned exactly to the level using a special tool. After installation, the far part of the window sill will be tight adjoin the window frame, and the next one will be exactly level. This will deceive your vision and create a visual effect. the correct location.

The installation of the windowsill can be combined with the installation of plastic overlays for corners near the window. Never rush in the process especially during markup. We are interested to know what nuances you personally noticed for yourself. Share your observations in the comments.


Watch the video tutorial from the installation professional windowsill PVC. All the nuances are clearly:

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