How to install slopes from a plastic panel of the “mom-dad” type for a PVC window yourself

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So, you are going to install the slopes yourself. This work is not physically and technically difficult, but it requires a certain amount of time (it takes the same amount of time to dismantle the old and install a new standard PVC window). For non-professionals, it will take about 3-4 hours of free time per window. First, let’s look at what you need for this:

How to install the slopes yourself

Materials:plastic panel, plastic corners, liquid nail building glue, silicone sealant (white) or liquid plastic.

Comments:if your window plastic is matte, buy matte panels, if glossy – glossy; plastic panels are standard in almost all construction markets and stores from 3 meters, so before buying, measure all the parameters of the window opening (do not forget the depth !!!); liquid plastic is more reliable and stronger than silicone sealant, when solidified, it becomes almost one piece with the panel and window frame, but it must be used very quickly, due to the fact that it dries very quickly, therefore, for people doing this for the first time, I strongly recommend using silicone sealant ; if you do not have building and jewelry abilities, it is better to choose corners from the 25th); it is better to use one-component foam (less consumption).

Instruments:jigsaw or a special hacksaw for plastic with small teeth, a hacksaw for metal (definitely needed if you don’t have a hacksaw for plastic), miter box, glue gun, goniometer (malka), knife (office or kitchen), puncher or scarpel with a hammer (needed if there are protrusions in the window opening that will prevent the panel from standing exactly to the edge of the wall relative to the frame), tape measure, pencil, masking tape (convenient because after it the wallpaper does not come off, and there are no traces of dirt on panel and frame).

Comments:when working with the “mom-dad” panel, do not put blades with large teeth on the jigsaw – the plastic will tear mercilessly, up to large chips, which will cause you to throw out the workpiece.

Let’s get started:

Preparation of a window opening for installation

We take a knife and at a distance of 0.5 cm from the frame we make a shallow cut 1.5 cm in the foam, parallel to the upper and side profiles, at an angle to the frame. We clean everything that was cut out (with our hands faster). We check the opening for unwanted protrusions, you can do it with cardboard (someone with a good eye may not do this): insert one end into your cutout and press it against the edge of the wall. Where the cardboard is bent, shoot down there. You can do this with a blank, and not with a cardboard, but since the line of the wall edge may change, it is better to be careful. It is important that the opening is clean of all kinds of dust and dirt..

Comments:It is not necessary to remove the protective film from the window frame.

Measurement, manufacturing and installation of the upper workpiece from the panel

It is important! The first blank is always the top one. Using a tape measure, measure the length of the inner upper part of the opening (the one closest to the frame). Be sure to measure, opposite the rightmost and leftmost points of the frame, the depth of the upper part of the opening. We measure the length of the outer upper part of the opening (wall edge). Then we take the goniometer and measure the right or left corner of the transition from the upper inner part of the opening to the upper outer one (we lean the thick part of the protractor on the frame, and with the thin part we put it in the upper corner), and fix it. We mark the depth on the panel, from the side where the angle was measured.

Measurement, manufacturing and installation of the upper workpiece from the panel

We apply the goniometer with the thick part to the edge of the panel and the obtained angle (obtuse) is brought to the depth mark. We mark the depth for the other edge of the workpiece and connect them with the size of the length of the outer upper part of the opening. Now mark the length of the inner part of the opening along the edge of the panel from the marked corner and connect the lengths with a segment. You should get a trapezoid or something similar. We cut it out with a jigsaw or a hacksaw on plastic. We check to see if the size of the workpiece fits. To do this, insert the protrusion into the slot in the foam, and with the groove rest against the edge of the frame and tap it lightly with your palm so that there is no gap between the workpiece and the frame. Does not fit, we flatten. If from the edge of the wall to the outer edge of the workpiece is up to 1.5 cm., It’s okay, it will close with a corner. I went in, press it to the top, fix it with masking tape once. Holds, we leave in place.

Comments:Due to the likelihood of blots (pencil marks are poorly removed from plastic), it is better not to carry out all markings on the front side of the panel; for ease of installation, it is better to mark the depths from the side of the papa panel, do not forget to measure the protrusion of the papa so that there is no confusion with the depths; measurement, manufacturing and subsequent installation, it is better to do it together (especially for a three-section window).

We prepare a gun with glue, shake up the foam, make at least three cuts of masking tape – 15-20 cm each. Unhook the tape from the workpiece and bend it down. Fill it closer to the frame and in the middle with foam. Do not be too zealous, here it is only needed to create stiffening edges. We take a gun with glue and point-wise glue the edge of the workpiece. Press firmly up and fix the panel to the wall with masking tape.

Measurement, production and installation of side panels from the panel

When measuring side blanks, there are subtleties. If your window sill is installed at an angle of 88-102 degrees in relation to the window frame, then you should measure the length of the outer and inner sides of the opening in relation to the installed upper workpiece, as well as the upper and lower depths of the opening. If the condition with the window sill is not met, then you will also need measurements of the upper (frame – upper workpiece) and lower (frame – window sill) corner. Be careful when measuring! Shortage can lead to large and irreparable gaps in the joints..


We do the same operations as with the upper workpiece.

Measurement, manufacturing and installation of workpieces from corners

Just like the panels, the first blank is the top one. Remove the protective film on the corner. We measure the length between the outer joints of the corners of the panels. We take a hacksaw, (for metal or plastic) a miter box and choose the desired angle configuration. We file on both sides. The cut at the 45-degree angle should go diagonally upwards, i.e. when joining the sides of the upper and side corners, the cuts should be 90 degrees. Checked, adjusted, everything fits. We clean the notches from those parts of the workpiece that we sawed off with a hacksaw. This is necessary so that the silicone or plastic can lie on the cracks. For the side corners, we take measurements, only after mounting the upper workpiece.


First, take the top blank. We glue it point by point, unhook the adhesive tape that remained after fixing the panels. We press the corner and fix it with scotch tape. Likewise with the side.

You did: “Hurray!”, But nevertheless, the appearance of your work does not please you at all, some even shock. What’s next?

Sealing joints and cracks with silicone sealant

We take the gun, insert the sealant and, squeezing it out in one continuous strip, we slowly move along the gap or joint. Then we run our finger so that the sealant is evenly distributed over the gap or joint. We close up all types of connections: corner – corner, corner – window sill, panel – panel, panel – frame. Remember, if you are wrong somewhere, the silicone can always be torn off and done again. At the end of all work, the windows must not be opened for 9 hours.


for a two-section window:

  • Hacksaw for plastic – 70r., 1pc.
  • Miter box – 30r., 1pc.
  • Protractor – 30r., 1pc.
  • Plastic panel of the “mom-dad” type – 130 rubles, 1 piece, 3m.
  • Silicone sealant – 120r., 1pc.
  • Construction glue “liquid nails” – 120 rubles, 1 piece.
  • Gun for glue and sealant – 60 rubles, 1 piece.
  • Masking tape – 50 rubles, 1 piece.
  • Corner – 40r., 1pc, 3m.
  • Total: 770r.

In any construction company, you will be charged from 2.2t.r. for installing slopes for one window.

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