DIY Guide to Sealing Windows and Doors (Silicone and Foam), by The Aiden Project🔨 on YouTube. 19 min 46 s.
- Video length
- 19 min 46 s
- Time to do it
- 90 minutes
- Difficulty
- Easy
- Steps
- 9
What you need
Steps
Cut out old sealant and loose material with a utility knife, then brush the gap clean. Wipe the frame and wall dry so the new sealant can stick.
Check the size of the gap. Anything wider than about 5 mm, or deeper than 10 mm, needs expanding foam first rather than silicone alone.
Spray the gap lightly with water, shake the foam can and fit the straw. Fill no more than half the depth in short bursts, because the foam expands.
Leave the foam to rise and cure for about 20 to 30 minutes until tack free. Cut the excess back flush with a serrated knife, just below the surface.
Run masking tape along both sides of the joint to leave a clean line about 6 mm wide. Press the tape down firmly.
Cut the silicone nozzle at 45 degrees to match the joint width, load the cartridge into the gun and pierce the inner seal.
Push the bead into the gap at a steady speed, keeping the nozzle in contact with the surface. Smooth it with a wet finger or sealant tool in one pass.
Peel the tape off straight away while the silicone is still wet. Leave the bead to skin over for at least 30 minutes before touching it.
Seal the outside of the frame the same way. Keep the weep holes at the bottom of the window clear so rainwater can drain away.
Tips and common mistakes
Use low-expansion foam made for windows and doors, since standard foam can bow a frame as it swells.
Never block the weep holes at the bottom of a window, or water will sit in the frame and rot it.
Silicone will not take paint, so use a paintable frame sealant if you plan to decorate over the joint.
Work in dry weather above 5 degrees Celsius, as both foam and silicone cure poorly in the cold.
Questions
Can I just seal the inside and skip the outside?
No. The outside joint takes the rain and wind, so seal both sides for a proper air and water tight finish.
How long does expanding foam take to harden?
It skins over in about 20 to 30 minutes and cures fully within 24 hours. Trim it once it is tack free but still slightly soft.
Can I fill a wide gap with silicone only?
Silicone shrinks and sags in deep gaps. Pack anything over 10 mm deep with foam or backing rod first, then seal over it.
This guide was drafted from the video's details and general task knowledge. It has not been checked against the full video. Check the video and relevant product instructions before following a procedure. Report a correction.
