How To Prevent Draughts in Your Home

How do you prevent draughts in your home?

Draughts are one of the major reasons rooms feel cold and uncomfortable, and sealing the gaps around window and door frames makes a real difference to both comfort and running costs. The work itself is straightforward. What decides whether it lasts is choosing the right product for each location, because the gap fillers in the Selleys range are not interchangeable — the interior product is not rated for outdoor use, and none of the caulks are intended for a cavity more than 10 mm wide.

This page covers the whole-house approach: finding the leaks, matching a product to each gap, and the technique that gets a bead to stay put.

Step 1 — find the leaks

Light a match or candle near any window or door where you suspect an air leak. If the flame dances around, air is flowing through the area. The movement of the flame should intensify — or the flame will blow out — as you move closer to the source.

Work methodically rather than assuming. The gap you can see is not always the one letting the cold in, and the leak is often at the head or the sill of a frame rather than the vertical joints. Doing this first also stops you caulking joints that do not need it.

Step 2 — match the product to the gap

This is where most draught-proofing goes wrong, so it is worth setting out plainly.

Interior gaps up to 10 mm wide

Selleys No More Gaps Interior Multipurpose is the general-purpose choice inside. It is water-based, has a skin time of 20 minutes at 23°C and 50% humidity, and a movement capability of up to 15% so it copes with normal building movement. For optimum paint crack resistance, filled gaps should not exceed 10 mm wide and 5 mm deep.

Exterior gaps

Do not use the interior product outside. Its technical data sheet states it is not recommended for exterior use or for areas exposed to constant water. Use Selleys No More Gaps Exterior instead. It uses a titanium compound to protect against UV and weather damage, has a movement capability of ±25%, a skin time of 30 ± 5 minutes and a tack-free time of 45 ± 5 minutes. Protect it from water for 24 hours after application to let it strengthen, and do not store or apply it below 10°C.

This matters because sealing a window frame on both the inside and the outside of the house is genuinely good practice for draughts — but it means using two different products, one on each side, not the same cartridge for both.

Gaps bigger than 2 cm

Caulk is the wrong tool for a cavity. Use an expanding foam such as Selleys No More Big Gaps, a polyurethane foam formulated to fill large or irregular holes and cavities — around pipes, behind skirting boards and architraves, and around door and window frames — to block draughts, noise, pests and birds.

Where a colour match matters more than paint

No More Gaps Coloured Gaps is made for joints where you want a finished colour without painting afterwards.

Where you need to paint quickly

No More Gaps Interior Fast Dry has a skin time of 6 minutes and is paintable in 10 minutes with gloss and low-sheen paints. Flat and ceiling paints still need 100 and 120 minutes respectively.

Step 3 — clean the area to be sealed

To ensure proper adhesion, remove any old caulk and paint before you start filling, and make sure the area is free from dust, grease and loose or flaking paint. A putty knife handles most old caulk. For old paint, a stripper such as Selleys Kwik Strip can be used — but read its limits first. Kwik Strip is solvent-based, must be used outdoors only with gloves, must never be used with a hot air gun or torch, and is not suitable for application to fibreglass, PVC, acrylics, linoleum, rubber or plastics.

Step 4 — prep the gun and run the bead

Cut the seal at the top of the cartridge with a knife or secateurs.
Cut the nozzle at a 45° angle, with an opening approximately the size of the hole being filled.
Fit the nozzle to the top of the cartridge and insert it into the caulking gun by pushing the base of the canister into the gun.
Apply steady pressure to the trigger to force the gap filler into the area causing the leak, moving the nozzle along the joint in one smooth action.
At the end of each section, wipe the excess away with a finger, spoon or spatula dipped in a 50/50 mix of water and detergent.
Clean off any excess with a damp cloth immediately.
Allow the filler at least 30 minutes to cure if you are planning to paint over it — longer for flat and ceiling paints, and 24 hours for oil-based paints.

For a neater finish and easier clean-up, tape both sides of the gap before applying the product and pull the tape while the bead is still wet. There is a fuller guide on using a caulking gun if this is new to you.

Why the gap size limit matters for draught-proofing

People sealing draughts tend to reach for one cartridge and use it on everything, and the 10 mm by 5 mm limit is the reason that fails. The effects of sealant shrinkage are more evident in larger gaps, which gives a greater propensity for the paint over the bead to crack. A cracked bead is an open bead, and the draught comes back.

The movement figures tell the same story from a different angle. Interior Multipurpose handles up to 15% movement; the exterior product handles ±25%, which is what an outdoor joint going through daily temperature swings actually needs. Where movement is excessive, or where a joint sees frequent water, Selleys directs you to an appropriate silicone sealant rather than any gap filler.

Limitations to keep in mind

No More Gaps Interior Multipurpose: interior only; low water resistance, so not for permanent immersion or constantly damp areas; not for polyethylene, polypropylene or Teflon; not for gaps between tongue-and-groove boards or weatherboards.
No More Gaps Exterior: maximum gap 10 mm wide by 5 mm deep; not for sealing around bathtubs or kitchen sinks; not to be stored or applied below 10°C; use a silicone sealant where joint movement is excessive or water immersion is frequent.
No More Big Gaps: exterior applications must be protected with paint, sealant, filler or another opaque material; once opened, the can should be used within 4 weeks.

Common questions about preventing draughts

How do I find a draught I can feel but cannot see?

Move a lit match or candle slowly around the frame. The flame will move more strongly, or go out, as you approach the leak.

Can I use one product for the whole house?

No. The interior gap filler is not recommended for exterior use, and neither interior nor exterior caulk suits a cavity wider than about 10 mm. Match the product to the location and the gap size.

How long before I can paint over the filler?

At least 30 minutes if you are painting over it, and longer with flat or ceiling paints or in cooler conditions. Allow 24 hours for oil-based paints.

What about gaps wider than 2 cm?

Use an expanding foam such as Selleys No More Big Gaps.

Should I seal the outside of the window frame too?

Sealing both the inside and outside of a frame is good practice for draughts, but use No More Gaps Exterior on the outside — the interior product is not rated for it.

How cold is too cold to apply it?

No More Gaps Exterior should not be stored or applied below 10°C. Cooler conditions also extend the time before you can paint.

Can I fill draughts around a bath or sink the same way?

No. No More Gaps Exterior specifically excludes sealing around bathtubs and kitchen sinks, and the interior product has low water resistance. Wet areas need a silicone sealant.

Do I have to strip the old paint before caulking?

Remove old caulk and any loose or flaking paint. Sound, well-adhered paint is fine to caulk against; flaking paint is not.

Is Kwik Strip safe to use indoors on a window frame?

No. Its directions say to use it outdoors only, because methylene chloride vapour is harmful on prolonged exposure. It is also unsuitable for fibreglass, PVC, acrylics, linoleum, rubber and plastics.

Which other gaps are worth sealing?

The joint between skirting boards and walls is a common one — see how to fill gaps between skirting boards and walls — along with window frames, covered in how to fill gaps around windows.

Will sealing gaps cause condensation problems?

Selleys does not publish guidance on ventilation, so this page cannot answer that. The products above are for sealing gaps; decisions about a home's overall ventilation are outside what the product documentation covers.

What is this Selleys page about?

The page, titled 'How To Prevent Draughts in Your Home,' is a Selleys guide showing how to prevent draughts and improve energy efficiency in the home in order to keep it warm and comfortable.

Which areas of a home are common sources of draughts?

According to the knowledge-base context on this topic, common draught sources include gaps around window and door frames, pipes, skirting boards, and architraves (the decorative trim around doors and windows).

How can I seal draughts around windows and doors?

You can seal around window and door frames using appropriate sealants and gap fillers designed for these applications, use expanding foam fillers for larger gaps around door and window cavities, and apply windscreen sealants specifically designed to prevent draft penetration through gaps around windows and windscreens.

What products help stop draughts around pipes and skirting boards?

Draughts around pipes can be filled using expanding foam or specialized gap fillers, gaps where skirting boards meet walls and floors can be sealed with the same, and gaps around architraves should also be addressed to prevent air leakage at these junction points.

What are expanding foam fillers and how do they help prevent draughts?

Expanding foam fillers are products that expand 2-3 times their original volume, completely filling large or irregular-shaped gaps. They provide excellent insulation against heat and cold while also reducing noise and preventing pest entry.

Which Selleys expanding foam products are suitable for draught prevention?

Both No More Big Gaps and Pro-Trade Expanding Foam Filler are suitable expanding foam products for interior and exterior applications when properly protected.

What should I use for smaller gaps and cracks around doors, windows, and skirting boards?

For smaller gaps and cracks, gap-filling products like Selleys No More Gaps Interior options can be applied around door frames, window frames, and skirting boards to create effective seals.

Who publishes this draught-prevention guide and what is Selleys?

The guide is published by Selleys, an Australian adhesives, sealants and fillers brand founded by Martin Selley in 1939 in Sydney, Australia, and a division of DuluxGroup (Australia) Pty Ltd.