For windows that open, buy draught-proofing strips to stick around the window frame and fill the gap between the window and the frame. There are two types:
Sliding sash windows are notorious for being draughty and foam strips do not work well. It’s best to fit brush strips or consult a professional. For windows that don’t open, use a silicone or foam sealant. This special type of foam can be sprayed into gaps around windows or doors, however it is more expensive than the foam strips.
We recommend you avoid insulating window film – also known as secondary glazing film. You tape this transparent film onto the window to create a double-glazing effect however it stretches and tears easily and you have to replace it regularly.
Draughts also occur in cracks between the window frames and the surrounding walls – in this instance use sealant or putty for best results.
Draught-proofing outside doors can save a lot of heat and will only cost you a few pounds. Here are the main things to consider.
Put strips of draught-excluding material around the hatch edges.
Use sealants to fill gaps around the fittings.
You can block cracks by squirting filler into the gaps. Floorboards and skirting boards often contract, expand or move slightly with everyday use, so you should use a filler that can tolerate movement – these are usually silicone-based. Look for the following:
Fillers come in different colours and for both indoor and outdoor use. They block gaps permanently so be careful when you apply them – wipe off any excess with a damp cloth before it dries. Fillers may break down over time, but can easily be reapplied.
Also check if there are draughts between the skirting board and the floor and seal as necessary. Ideally you should insulate the void under the floor.
You can fill in cracks using cements or hard-setting fillers, but if it’s a large crack there may be something wrong with your wall. Consult a surveyor or builder to see what caused the crack in the first place.
You can fill small gaps around pipework leading to a loft or the outside with silicone fillers, similar to the fillers used for skirting boards and floorboards. Fill larger gaps with expanding polyurethane foam. This is sprayed into the gap, expands as it dries, and sets hard.
If you don’t use your fireplace, your chimney is probably a source of unnecessary draughts. There are two main ways to draught-proof a chimney:
Remember to remove the draught-proofing if you decide to light a fire!
Old fan outlets may need to be filled with bricks or concrete blocks and sealed from both the inside and outside.
Disused vents may be left behind after gas fires and old central heating boilers, with non-balanced flues, are removed. These should be sealed up, perhaps with an adjustable vent cover, or you can fill them with expanding polyurethane foam.
You should block most of these – but be careful in areas that need good ventilation, such as:
For example, where brickwork needs re-pointing – add new or top-up mortar between the bricks.
Air needs to flow in and out of your house so it stays fresh, dry and healthy. Make sure you don’t block or seal any intentional ventilation, such as the following:
Keep good ventilation in areas where there are open fires or flues and in rooms where moisture is produced.
Don’t seal kitchen and bathroom windows – this lets out the steam and helps create ventilation. Instead, seal the inner doors to these rooms.
There are plenty of DIY stores that sell draught-proofing materials, but look for draught-proofing with a Kitemark – this shows that the product is made to a good standard. British Standard Institution accredited products have a 20-year life when correctly installed and maintained.