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Are you unknowingly heating your loft?

The headlines

IMPORTANT....this is not about insulation!

It is about unnecessary heat loss in built-in cupboards and problems left after historical wiring or plumbing activities.

This sort of heat loss can lead to condensation in a loft if there are damp and condensation issues in a home. Loft condensation can lead to rotting roof timbers if not dealt with.

Airing cupboards (or ex-airing cupboards) are the most common culprit, but it can be ANY cupboard.

Below are some eye-opening pictures and guidance on fixing these problems simply and easily.


Here is a photo I took, using my thermal-imaging camera, of a house that had holes in the ceiling of the airing cupboard. It shows how warm the roof is: a lovely warm patch of roof, oozing money! This is the problem I'm about to talk about.

This was caused by the hot water tank in the airing cupboard below - the sort of setup around half of UK homes still have.

Although many homes now have combi boilers and no longer have hot water tanks, many still have airing cupboards that USED to have a hot water tank, often with warm pipes in them, boilers in them, and even radiators in them sometimes.

Just peer upwards in any built-in cupboard or wardrobe and check out yours. You might go 'EEK'!

Even if you don't have a hot water tank or boiler in a cupboard, any holes left in the ceiling will be helping your loft warm up.

While these sorts of gaps won't be letting cold air in, because heat rises, leaks in the house like this actually make it easier for cold draughts to come in from gaps lower down in the house. For every cold draught coming in, there is warm air leaking out!

Holes like this leak warm air out of a home every minute of every day in cold weather.

Below are some examples.

Example 1

This is typical of what I see. As well as the obvious hole, you can see cracks between the ceiling and the wall. These need plugging too, as they will also be leaking hot air into the loft. They will probably be leaking the warmest air in the house into the loft!

You can easily fix these problems with DIY tube sealants, but make sure that you use Firestop sealant, which helps to prevent the spread of fire through the hole you are filling. It is cheap, such as around £5 here from Toolstation.

Example 2

This is also very common. The fix is the same stuff as above, but use plenty of it and make sure you get it behind the pipes too. This is a good opportunity to check whether the pipes up in the loft are insulated too.

Example 3

This may just look like a small crack between a ceiling and a wall, BUT it is still important to seal up, as it'll be silently seeping heat and money forever until it is blocked up, which only takes seconds to do.

Example 4

This is the worst I have seen. Excruciatingly bad! Scary! The largest hole is big enough for me to actually put my arm through, direct up into the loft space. This airing cupboard actually felt cool, despite having the boiler and hot water tank in it! The family living in this house had no idea these holes existed, and it is very doubtful that any of the pipework in the loft will have been lagged either.

This will take a bit more than just firestop gunge to fix.

As mentioned at the start, this isn't something unique to airing (or ex-airing) cupboards.

Any cupboard that has pipes or cabling (including alarm and TV aerial cables) going up into the loft can be guilty of this heat loss sin.

Also, do look out for places where pipes or cabling run from inside the house into unheated area, such as garages.

If you have loft condensation issues these can easily lead to serious issues of rotting roof timbers. See my series of blogs on damp and condensation here to better understand how to solve this problem.


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All content on the site should be treated as information and not advice. You should take professional advice where appropriate to different site articles.


Mark Thompson

Get Energy Savvy - simple practical home energy efficiency information

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1 Comment

Mar 13, 2023

So how do you fix scenario No 4?

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