Plastic window sills: installation technology

At the final stage of the installation of a plastic window, the window sill is installed. The window sills are almost always mounted by the same craftsmen who installed the window itself. But sometimes there is a need for self—installation of the window sill - you either have to mount the window sill board yourself, or call the master.

What you need to know about installing a PVC window sill and how to install it in different openings — we will tell you below.

Choosing the size

In addition to choosing a window sill model, you need to determine the size:

• In width, it is desirable to make a margin on the left and right to place the edges of the window sill behind the slopes. This way the structure will look more attractive, and the edges of the slopes will be additionally fixed. Add 50-70 mm on each side.
• The depth of the window sill depends on the installation location and usage plans. The minimum size is 100-150 mm, the maximum is about 600 mm. The wider the window sill, the larger its usable area will be: at a depth of 200 mm, you can use a plastic window sill as a shelf, at a depth of 450 mm — as a countertop.

Pay attention! The deeper the window sill, the higher the load on it. If the outflow exceeds 150 mm, you will have to install additional brackets.

Important rules

When installing plastic window sills, you need to follow several rules:

• It is not necessary to install the board strictly horizontally. A slope of about 1-2 ° towards the room will ensure condensate runoff, and puddles will not appear on the windowsill.
• There should not be less than 100 mm between the upper edge of the battery and the lower edge of the window sill. Otherwise, the window sill may overheat, which will lead to plastic deformation. In addition, the window sill will block the trajectory of warm air — because of this, the double-glazed window will be supercooled, and condensation will begin to form on it.
• The removal of the window sill beyond the wall plane should not completely block the battery — this will also cause excessive condensation. When installing a window sill with a large width, grilles are cut into it for the circulation of warm air, which should heat the double-glazed window.

Installation of the window sill with your own hands

When installing the window sill on your own, you need to prepare the opening. Preparation consists in performing preliminary operations:

• Leveling the base — it is enough to remove large bumps and swells.
• Cutting grooves in the edges of the opening — the edges of the board will be wound in them.

 There are several techniques for installing window sills

On glue or mortar

When installing a window without a support profile, the window sill can be fixed directly on the surface of the opening using cement mortar or adhesive composition. The base should be as smooth as possible, without distortions and bumps:

• The surface to which the window sill will be attached is treated with a primer.
• The solution is laid in a thin layer, adhesive strips 1 cm wide with a step of about 10 cm.
• The window sill is placed under the frame and pressed against the base.
• The oppression is put on the board and not removed until the glue or solution polymerizes.

After polymerization of the solution or glue, it is necessary to treat the joint of the frame and the window sill with a sealant.

On the mounting foam

Self—expanding mounting foam has good adhesion, strength and thermal insulation - so it can also be used when installing a window sill. Before installation:

• Gaskets are placed on the base, exposing them in increments of 50 cm in level.
• Holes are drilled in the lower part of the window sill (between the internal partitions). This is done so that the foam penetrates inside and additionally fixes the window sill.
• Brackets in the shape of the letter Z are attached to the support profile.
• The window sill board is fixed on the brackets and pressed against the support pads using a bend.
• Mounting foam is blown into the gap between the base and the window sill.

To prevent the window sill from deforming as a result of the secondary expansion of the foam, the oppression is not removed for at least a day.

On the console

If you need to install a deep window sill with a large overhang, the technology described above is modified:

• The consoles are attached to the bottom of the window sill with a step of about 50-70 cm .
• When the window sill is fixed and aligned, holes are drilled through the grooves of the consoles in the wall.
• The consoles are fixed with fasteners (a plastic dowel with a wide neck).
• As in the previous case, the space under the window sill is filled with mounting foam.

On the bracket

A combination of load-bearing consoles and brackets is used when installing window sills on balconies:

• The brackets are attached with screws to the support profile with a step of about 25 cm.
• The window sill is snapped on brackets.
• For additional fixation of the window sill, load-bearing consoles are installed. The size of the console is chosen in such a way that the size of the ledge of the window sill over the edge does not exceed 10 cm.

The reliability of the fastening directly depends on how rigidly the console will be fixed on the window sill and on the supporting structure.

How to join window sills

When installing window sills, they often have to be joined — either at an angle or in one line. When docking, it is worth following simple rules:

• Be sure to leave a gap (for 1 m of the window sill — 1.5 mm) to compensate for the temperature expansion. If the gap is not left, the window sill board may deform and bend.
• The joint should be reinforced with brackets — they are placed about 3-4 cm from the joint line on each side.
• Additionally, you can strengthen the joint with an overlay — it is installed on the wrong side and fastened with screws.
• The joint line is covered by a special decorative profile that covers the gap, but retains the mobility of the joint to compensate for deformations.

You can install a window sill on your own — especially if you follow all the recommendations given in the article. But even such a simple operation has a number of nuances that must be taken into account. So the optimal solution would be to entrust the installation of a plastic window sill to highly qualified specialists — especially if we are talking about a premium-class window sill or the installation of a complex structure with several joints.

You can order a window sill by following the link