Sealing of windows

Sealing of windows

Use a weatherproof and UV resistant sealant to get a beautiful, clean finish around the exterior window joint. The Soudal Trade Range: Exterior Frame Silicone is a flexible and weathertight sealant, perfect for sealing around the perimeter of wooden, aluminium, and PVCu window and door frames. Find out how to do this in our step-by-step guide.


1. Clean and dry the window frame and wall

Remove all dirt, grease and dust. Use a good quality degreaser around the window frame. First, brush the wall clean to remove any dust and dirt. Then go over it with a damp cloth. Allow drying thoroughly.

2. Tape off the joint edges

Use masking tape to neatly tape off the sealant edges. You will then work nice and straight. Make sure that the joint, both on the wall and on the window frame, is between 5 and 10 millimetres wide.

3. Open the cartridge

Cut the top off the cartridge with a safety cutter. Turn the nozzle on top and cut the end to a slant. To get the best result, cut the opening of the nozzle to the same size as the joint you want to seal. Put the cartridge in the caulking gun and squeeze the handle until sealant appears.

4. Start sealing

Place the nozzle where you want to start sealing. Squeeze the handle and move the caulking gun over the joint in a smooth movement. Apply sufficient sealant to ensure that the product adheres well.

5. Smooth and remove the tape

Wet your finger in the soap solution or Joint Finish. Smooth the joint and immediately remove the masking tape. Smooth carefully again to smooth away any protruding edges.

6. Rinse with clean water

Use the plant sprayer with clean water to remove soap residues. You then prevent soap from burning into the window frame.


  • The sealant does not adhere to damp surfaces. So do not seal if it has just rained or when thunderstorms are forecast.
  • Choose a sealant of the same colour as the joints in your façade brickwork to obtain a smooth transition between the window and the wall. Soudal’s Exterior frame Silicone sealant comes in white, grey, brown, black or clear. Do you have joints in another colour?
  • Note: Sealants can cause stains on natural stone. Do you have natural stone window sills under your window? Use Fix ALL Flexi to seal your joints.

The following is also useful:

  • • Soudal Surface Cleaner is a solvent cleaner to quickly remove grease and dust from surfaces. Test beforehand in a concealed place to check that no stains or colour differences are left behind.

You can find the technical sheet and all information about the use, shelf life, composition of Soudal sealants visiting the product page.

Trade Exterior Frame Silicone White 270ml
Neutral cure building and glazing silicone sealant
Fix ALL Flexi White 290ml
Hybrid polymer sealant adhesive

How to seal a window


Safety cutter

Masking tape

Clean cloth


Soudal Joint Finish or soap solution

Plant sprayer with clean water