Keep out draughts

How to fix door seals and insulate your home

Draughty doors compromise your home’s insulation, which is more costly than you think. Learn how to seal a door and reduce your next power bill!

How door seals protect your home

If draughts are entering your home, a gap underneath the door or between the door frame and wall is usually to blame. Not only is a draughty door uncomfortable, but it will also likely result in higher power bills. The solution? Seal the gap and insulate your home. It’s easier than you think!

First off, examine the door seal and isolate the gap causing the draught. You can do this by running your hand around the edge of the door frame.

  • If the gap is under the door, foam or brush seals (which can be glued to the bottom of the door) are your best bet to seal the door.
  • If the gap is between the door frame and brick wall, use a silicone rubber for your door seal instead.

Only use silicone as a sealant if adjacent surface materials (such as doorframes) aren’t coated or painted. Otherwise, use a silyl modified polymer (SMP) sealant or another paintable sealant.

How to seal exterior door frames

Filling around external door frames like front doors is a little more complicated and requires both a sealing hose and a sealant. Again, make sure you only use a silicone sealant for uncoated/unpainted surfaces, and a paintable sealant for coated materials.  

Here’s what you’ll need:

  • carpet knife
  • spatula
  • sealing hose
  • masking tape
  • cartridge gun
  • joint smoother
  • soapy water
  • paper towel


Then, simply follow these steps to add sealant around a door frame:

  1. Remove old sealant using a carpet knife or spatula.
  2. Using the carpet knife, shorten the sealing hose to fit the gap (work very carefully so as not to damage the sealing hose).
  3. Gently insert the sealing hose into the gap with a spatula.
  4. Attach masking tape to both sides of the gap to protect both the door and wall from excess silicone.
  5. Snip off the tip of the silicone sealant and insert the bottle into the cartridge gun
  6. Press the silicone slowly and evenly into the gap (ideally in one continuous action) to seal the door.
  7. Smooth the silicone while it’s still malleable (you have a few minutes to do this) by dipping the joint smoother in the bowl of soapy water and running the tool evenly and quickly over the sealant.
  8. Remove any excess silicone with a paper towel. 
  9. Pull off the masking tape before the silicone sealant sets. If there are any rough edges, you might need to repeat step 7.