Insulating An Internal Door?

14 Sep 2020
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United Kingdom
So this door goes into the garage. The room this side is my 'mancave!' and is always freezing this time of the year! The door is just an old door with a single pane of glass. It fits tight against the slam strips. Without replacing the door for a more thermally insulated one, has anyone any cheaper ideas to keep the heat in the mancave? There is an uneven gap at the top of the door but the slam strips block that gap. As you can see, the radiator is next to the door too. The garage is freezing so it must be escaping through this door? Looked at thermal door curtains etc, but I thought I'd ask some experts first! Any help would be amazing! Thank you in advance!

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whats above the room ??
not as simple as the doors fault unlikely to be more perhaps 10% loss through a door with decent seal all round
is there a gap at door bottom edge ??
and heavy lined curtain from a basic curtain emporium add words like thermal or any other buzz words add many ££
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I'd start by replacing it with a fire door, if that isn't one it should be. 44mm thick with intumescent strips (which usually come with a draft seal as well).

I'm in the same situation having built a garage on the side of my house so I need to replace the existing uPVC door with a fire door - I don't think you can get an especially thermally efficient domestic fire door so I'm wondering as well - and I don't think attaching insulation to a fire door is a good idea. I'm thinking like you that some kind of thermal curtain might help.
looking again i think the term "slam strips" that i assumed where rubber seals added may just be the door stop so maybe added door seals needed and with the rolly polly at the bottom suggests heavy draughts that need attention
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Quite so. If it is an actual garage, it must have a fire door.

You can identify the source of draughts with a smouldering joss-stick, but not, of course, when there are vehicles or flammable liquids in there.

Is the wall between your room and the unheated garage an insulated cavity wall?

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