Floors & Ground Floor
Cold and draughty floors come from uninsulated ground floors and air leaking up from the void below. Damp under the boards is a ventilation problem worth catching early.
Why are my floors cold?
Cold floors are one of the most-felt comfort problems, and they have two clear causes: the ground floor is poorly insulated so heat is conducted away into the cold ground or ventilated void below, and air leaks up through gaps in the floor carrying cold draughts. Because you are in direct contact with the floor, even a slightly cold surface feels uncomfortable — and the fix depends on which mechanism dominates.
Read the guideWhy is my ground floor so draughty?
A draughty ground floor is usually cold air leaking up from the ventilated space beneath a suspended timber floor, through the gaps between floorboards and around the skirtings. The under-floor ventilation is there for a good reason — to keep the timbers dry — but the gaps let that cold air into the room. The fix is to seal the room side without blocking the ventilation the floor structure needs.
Read the guideShould I insulate my floor?
Floor insulation can make a real difference to comfort and heat loss, but whether it is worth it — and how to do it — depends on your floor type, how much it is losing, and the moisture conditions below. Done well it warms cold floors and cuts draughts; done without regard to ventilation and moisture it can cause problems. Deciding sensibly means understanding what your floor is and measuring what it is actually losing.
Read the guideDo I have damp under my floorboards?
Damp under the floorboards of a suspended timber floor usually shows up as a musty smell, cold or damp-feeling floors, or — in worse cases — soft, decaying timber. It is generally caused by poor under-floor ventilation, ground moisture in the void, or blocked air bricks, and left unchecked it can rot the floor structure. Confirming whether you have it, and why, is the first step to protecting the floor.
Read the guideShould I insulate my concrete or solid floor?
A solid concrete ground floor can lose a meaningful amount of heat and feel cold underfoot, so insulating it is often worthwhile — but unlike a suspended timber floor, which can usually be insulated from below, a solid floor has to be insulated from above (raising the floor level) or as part of a larger dig-out, which makes the decision more involved. Whether it is worth it depends on how much heat the floor actually loses, the practicalities of raising the floor against doors, stairs and ceiling heights, and whether you are already planning works that make it easy. The right answer comes from weighing the heat loss against the disruption — ideally informed by a measurement of where the home loses heat.
Read the guideWhy is there a cold draught coming from under my skirting?
A cold draught at the bottom of the wall, where the skirting meets the floor, almost always means cold air from the void beneath a suspended ground floor is leaking up into the room through the gap there. Suspended timber floors are deliberately ventilated underneath by airbricks to keep the timbers dry, so the void is cold and breezy; where the floorboards meet the wall, and the skirting doesn't seal the junction, that cold air is drawn into the room — especially as warm air rises and escapes higher up, pulling replacement air in low down. It is a classic, very fixable air-leakage path.
Read the guideShould I insulate a suspended timber floor?
Insulating a suspended timber ground floor is usually well worth it if the floor is cold and draughty, because these floors sit over a cold, ventilated void and lose a lot of heat both by conduction and by air leaking up through the boards. Done properly — insulation supported between the joists with the air leakage sealed, while the void's airbricks are kept clear — it warms the floor, stops the ankle-level draughts and cuts heat loss noticeably. The key is to combine insulation with airtightness and to preserve the under-floor ventilation that keeps the timbers dry, so the floor is warm without putting the structure at risk of rot.
Read the guide