How to properly install windows and doors yourself

Tools needed : tape measure, spirit level, impact drill (preferably pneumatic), cordless screwdriver with extended attachment - Torx 30, 6 mm concrete drill bit, 6.5 mm panel drill bit, low-expansion foam, silicone gun, butyl sealant, washers of various widths, wedges, turbo screws, vapor barrier tape for exterior and interior with bitumen, vacuum cleaner, foil for covering the floor, PZ2 screwdriver bit, snap-off knife. steps.

1. Correct focus (the most important step!)

We measure the outer partition (the main decisive dimension) and for checking also the inner partition → steel tape measure.

The goal is for the window to aesthetically fit well with the facade from the outside (it can be partially recessed behind the plaster / insulation).

Interior plaster is much easier to repair than exterior facades.

During a complete renovation, consider moving the window as close to the outer edge of the facade as possible (due to future insulation → better thermal insulation + smaller external window sills).

Subtracting reserves (gaps for assembly):

Width → measured outside dimension − 3 cm (1.5 cm left on each side for alignment and foam)

Height → measured dimension − 5 cm (3 cm due to the sill strip + reserve for comparison and sill)

For doors, we only subtract -2 cm from the height and check that they open well after installation (take into account any crooked floor!)

2. Correct assembly – step by step

Window preparation – sash removal

Turn the window handle 45° to the "open + tilted" position.

Pull the pin downwards on the upper hinge (click) → the sash is released.

Tilt and slide the sash upwards from the bottom hinge → set aside.

Preparing the frame (before installation):

a) Gluing sealing tapes (very important for long life!)

On the inner edge of the frame → vapor barrier tape (marked INT / internal)

On the outer edge of the frame → vapor-permeable / waterproof tape (marked EX / external)

In the corners, let the strips overlap by 5–10 cm → this will allow you to create a watertight corner.

Glue the strips so that they can be pressed well onto the lining later.

b) Anchoring straps / anchors

We always start 15 cm from the corner of the frame.

Spacing between anchors max. 60 cm.

Never more than 15 cm from a corner.

We do not put anchors in the bottom part of small windows, but for larger ones we screw one into the center of the sub-window sill.

Caution! Never drill turbo screws directly into the bottom of the frame!

Fitting the frame into the opening:

c) Prepare two pads (15 cm from the edge of the lining on both sides) → place the frame on them.

d) Place the frame on the pads → use a spirit level to check the horizontality of the lower frame (it must be perfectly straight and at the same distance from the edge of the partition → this will prevent it from sitting on an angle).

e) Check the verticality on the hinge side (from the front of the frame) → after alignment, secure the top with a wedge. From now on, do not move the bottom anymore!

f) Screw the left and right anchors at the bottom.

g) Check the verticality again (on the hinge side + inside the frame) → everything must be level → secure with an anchor.

h) Remove the wedge and repeat the comparison on the opposite side.

i) Check the entire window once again in all directions (level, diagonals) → only then screw in the remaining anchors.

Completing the assembly:

j) Fill the joint with low-expansion foam (shake the can at least 30 times first!)

Lather slowly from both sides.

Do not fill the joint completely → allow for expansion of approx. 15%.

k) After about 10 minutes (when the foam is non-sticky to the touch), carefully press the excess foam inwards → this will prevent cutting later (cut foam is more absorbent).

l) Put the sash back on (reverse procedure to removal) → close the window and leave it closed until the foam has completely hardened (usually 24 hours).

m) Stick the tapes on the lining (the substrate must be dry, clean and dust-free).

Tape the joints thoroughly in the corners.

Seal any leaks with bitumen sealant (from the cartridge).

n) Vacuum/blow dust from the frame → check opening and adjust the fittings if necessary.

Important tips in conclusion:

The most common mistakes → poor alignment, overly expansive foam, poorly applied tapes, drilling into the bottom frame.

If you are not sure, it is better to call a professional - poor installation can worsen the insulation properties by up to tens of percent.

Good luck with the installation! If something is unclear, feel free to write. 😊