How to seal gaps under and around doors and windows

Sealing external doors can reduce air leakage by 12%.

Gaps under and around doors, especially external doors, are probably the easiest gaps to identify and fix. In winter, cold air will come in under the door and cause an unpleasant draught. By using door ‘snakes’ or installing draught excluders at the base of doors, as well as draught strips and/or draught seals around doors, you can stop the cold air from getting in and the heat from getting out in winter. These products will also help keep the heat out in summer.

Step 1: Getting started

Check for gaps around doors and at the base of doors that lead to the outside, but also check doors to the garage and to areas that have permanent ventilation. Some bathrooms, toilets and laundries have fixed open windows, so the doors to these rooms should have door seals as well. Don’t forget to also check windows, as many of the products used to seal draughts around doors can also be used to seal draughts around windows.

Step 2: Fixing the problem

There are many products on the market designed to be fitted to doors to seal up gaps, so it pays to do a bit of homework before heading off to the hardware store. You will need to note whether the door in question opens inwards or outwards, and the type of flooring it opens over (timber, carpet, tiles, etc.). There are also different products for internal doors, so make sure you choose the right product for each application.

Draught excluders

If you need to seal around the edges of your doors (the door jamb), check how big the gap is so that you can choose a seal that will fill the gap. These seals are normally made from foam rubber or plastic and are available in rolls. Each door will use approximately 5 metres to seal, but it pays to measure and count your doors before you go shopping.

Draught stripping

Step 3: Sealing around windows

Windows often require draught proofing between the openable sash and the window frame. There are a range of products for different situations and these draught proofing products will usually have their application clearly marked.


Always prepare the surfaces you are intending to seal by ensuring they are clean and dry. Dirt and oily residue will prevent adhesive seals from sticking properly.

Tools needed

Whilst attaching a draught seal at the bottom of the door is not a challenging job, it does require some basic tools. The seals are generally wider than the door and will need to be measured and cut to size before being attached. When attaching the seal to the door, it’s a good idea to screw the seal onto the door; don't rely on the adhesive alone.

  • Draught strips
  • Hack saw
  • Drill
  • Nails
  • Tape measure
  • Pencil

More information

If you need to know how to seal up other areas around the house, this information is covered in the following guides: