Sealing Your Exterior Windows & Doors (2018 guide)

How to seal an exterior window and door


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What silicone sealant should I use? 

Before you start it’s recommended that you buy a Low Modulus silicone sealant, for external use as this will be water resistant.

Quick checklist: 

  • Low modulus silicone sealant
  • Silicone gun
  • Razor knife
  • Sealant remover
  • Bucket of warm water & sponge
  • Ladder
  • Dry weather

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Take off old sealant around edges

Remove any broken or old sealant around the edges with a razor knife. If necessary apply sealant remover with a brush, sit down, have a coffee, then come back and remove the rest. Onto step 3!

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Sealing window with silicone

Sealing the frame

Cut the tip off the tube (if there’s an additional seal on the tube, use a nail to pierce this) and place it into the silicone gun.

Push the handle until you feel resistance, then hold it at a 45 degree angle and carefully start laying the silicone along the gaps between the window / door and the surface. Try to keep a consistent line, as a messy application may be visibly unattractive after it dries up.

Smoothing silicone with finger

Remove excess silicone sealant

The silicone should usually be touch dry in 60 minutes (or the time the instructions state). If you have any excess silicone left over, and particularly if you have a big job, use a wet sponge or wet your hands and smooth over the silicone as you go.

If you find some excess silicone after it’s fully cured, you can still remedy this by using the razor knife and cutting off the excess, then using a wet sponge go over the area to remove any excess bits.

Good luck, and if you liked this post be sure to check out our other home improvement tips.

South Coast Windows
South Coast Windows, based in East Sussex, supply and fit UPVC Windows, Doors and Conservatories to the South Coast region of the UK.
South Coast Windows

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