Sons bedroom is freezing (above garage)

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So our house is relatively well insulated overall.

However my sons room (He is 2) is directly above the integral garage.

As a result that room and that room only is always freezing, the integral garage is not insulated and doesent have any heating, the ceiling does have plasterboard on it BUT i imagine there is no insulation between the plasterboard and the floor joists above, if there was i cant imagine his room would be as cold as it is.

To save ripping plasterboard off first and making a big job is there anything i can fix to the current plasterboard like an insulating board on top of the current board? I could try fix it into the floor joists too but would this cause any damp issues by putting board on top of board?

Would drilling multiple holes and spraying expanding foam in do a similar job or would that create issues later down the line? There is a light in the garage so there id definately an electric cable under the plasterboard.
 
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without removing the plasterboard in the garage you wont deal with the thermal bridging at the perimeter

sure, overboarding with insulated plasterboard will help, but it wont get near the required insulation level

Id do it properly if it was me -given energy prices this winter
 
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If there is already insulation between the plasterboard and joists above whats my next option? Glue some kingspan plasterboard to the current plasterboard?
 
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If there is already insulation between the plasterboard and joists above whats my next option? Glue some kingspan plasterboard to the current plasterboard?
if its fairly old the only insulation would be a bit of fibre glass type loft type insulation.

removing it and replacing with PIR rigid insulation and foamed joints +returned at the perimeters would make a huge difference

the best way would be say 100mm in between joists and insulated plasterboard below
 
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You could lift a couple of floorboards and pour in loose lay insulation .Use a rad calculator to check you have suitable sized radiator in there .
 
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Does the room have a carpet?

Heat loss via floors is mostly due to draughts. Worst through the gap under the skirting boards.

There is no convection downwards, very little conduction, and practically no radiation.

Start by going into the garage and looking for gaps round the edges of the ceiling, and around pipes, cables and lighting fittings. You can buy pink fire resisting expanding foam in aerosol cans

For the best job, you need to take up the floor, hoover out dust and rubbish, and pack with mineral wool, which as well as being a good insulator, is very good for filling voids and blocking draughts. It is non-combustible and can be pushed into irregular gaps with no precision cutting needed.

Taking up a floor is an easier DIY job than remaking a ceiling.

Start round the edges of the room against external walls, which will be worst.

How thick is the loft insulation in this room?
 
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Sorry to hitch a ride on this thread but we have exactly the same problem. Our house is about 20 years old so I would assume that it is reasonably well insulated but the bedroom over the garage is noticeably colder than the rest of the house.

I have read through the suggestions above and the advice all seems to point to taking the bedroom floor up to insulate but ours has chipboard flooring rather than floorboards so I am a but reluctant to start ripping it up (not sure how to if I am honest).

I came across this stuff and wondered what the feeling was on it's effectiveness? Is it likely to be a waste of time and money?


Thanks
 
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I came across this stuff and wondered what the feeling was on it's effectiveness? Is it likely to be a waste of time and money?

Generally, a waste of money. It will help stops drafts through floorboards, if you have no floor covering at all, but in your case you have chipboard. You need to tackle it as per the replies above, but what is the composition of the walls?
 

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I have read through the suggestions above and the advice all seems to point to taking the bedroom floor up to insulate but ours has chipboard flooring rather than floorboards so I am a but reluctant to start ripping it up (not sure how to if I am honest).

Chipboard is an awful material, ideally suited to the skip. It is quite easy to remove, but will not be fit to put back afterwards.

The easiest tool is a circular saw, a pry bar, a couple of wide bolsters, and a big hammer.

Make your first few cuts, the blade depth set as close as you can get to the board thickness or fractionally less, to avoid nicking pipes, cables, hangers. Use a coarse TCT blade which will shrug off nails. Once you have a hole, zip the boards into convenient sizes to carry away, and start lifting them off the joists with your bolsters and bar. Mostly the nails will probably stay in place and you can pry them out. Wear knee pads. Have pincers handy.

You will also need ear defenders, a builders vac, rubble bags, dustpan and brush, dust mask, boards to kneel on.

I'd recommend ply as your new floor, screwed down, with pilot holes. Put struts (noggins) under all unsupported edges. It does not need glue.
 
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Its quite common for builders to "forget" to insulate the ceiling above a garage, but even 20 years ago it would have been a requirement to meet the U-value objective. The easiest option is to take out the plasterboard from below and pack the void with Rockwool, this has two benefits: 1 it insulates the space (not as well as celotex though) and 2 it gives fire protection, which is fairly important if you store anything with flammable liquids etc. Petrol etc. but even washing machines, tumble driers, battery storage. I would then re-plasterboard the ceiling from the garage, possibly even double board it (giving around 1 hour fire protection).

Also make sure any pipes in the void are properly lagged.
 
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Take the plasterboard down in the garage and do the job properly.
 
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Petrol etc. but even washing machines, tumble driers, battery storage. I would then re-plasterboard the ceiling from the garage, possibly even double board it (giving around 1 hour fire protection).

I thought it was a legal requirement, that it had to have a double thickness between garage and and such a room?
 

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