Garage ceiling insulation quote check

Garage ceiling insulation quote check

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Defcon5

Original Poster:

6,303 posts

198 months

Thursday 19th September
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I have a bedroom above my integrated garage that gets very cold.

I’ve had this quote from a company that did the same job at an identical house down the road several years ago (which the occupants said worked a treat)

Does it look like a good solution?



I thought they would use that stuff foam insulation but this is a fancy foil thing on a frame by the looks of it

Slagathore

5,965 posts

199 months

Thursday 19th September
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Is the current ceiling very uneven? I'm not sure why the need for 25mm battens? I would have thought they'd only counter batten so they could level it? Otherwise, just fix in to the old joists?

The foil is incredibly expensive, could they not achieve something similar with insulation backed plasterboard?

https://insulation4less.co.uk/products/celotex-pl4...

Even 10 sheets of that is less than the foil option alone and takes care of the plasterboarding?

Defcon5

Original Poster:

6,303 posts

198 months

Thursday 19th September
quotequote all
The current ceiling is PB, so even enough for that.

The house was built in about 2014 if that makes a difference to anything, and it’s a single garage (6mx3m ish)

LooneyTunes

7,561 posts

165 months

Thursday 19th September
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Defcon5 said:
Does it look like a good solution?
I looked at the foil insulation and it seems like it’s potentially good for radiant heat in some applications but that’s not how heat transfer is likely to take place through a garage ceiling? Were it me I’d be looking at PIR insulation instead. Did they offer this as an alternative?

The likes of kingspan and reticel have online calculators that can show performance and build-ups. Say 100mm between and 50mm underneath the joists, with fire-resistant plasterboard beneath would cost ~ £500 in materials (for that area you only need about 6 sheets)

You could easily have the old ceiling down and in a skip single handedly in a day then only another 2 (+/- 1) man days to get that amount of insulation cut and boarded. Not a tricky weekend project if you have someone to help you?

OutInTheShed

9,324 posts

33 months

Thursday 19th September
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A mate of mine went through this with a townhouse, as did his neighbour.

The heat loss was really far more to do with draughts running through the void of the garage ceiling. Sort that and whack £50 worth of rock wool in, job jobbed.

If you want to spend 4 figues, look at an insulated garage door, keep the garage warm along with the house.
You may want to look at some forced ventilation.

Also look at details, like how well the cavity of the wall is closed around the garage door.
Is there a bleedin great RSJ shaped 'cold bridge'?

Do the maths! Is the heat loss you're obsrving consistent with the garage ceiling void being a reasonably closed empty box of air?
Or is there a gale blowing through it?

My mate went for the insulated door, as he was also looking for better security after a burglary down the road, that and some draught proofing/cavity closure made a real difference.

Miocene

1,445 posts

164 months

Friday 20th September
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We got exactly the same job quoted last year from some builders working next door. It was a grand for them to pull down the existing board, I dispose of it, then they fill with rock wool, board and plaster. This was them doing it over a weekend, when their Mon-Fri job was for a local building co.

Didn't do it, but only because the electrics needs work in there too, but it's on the list.

Chris Type R

8,139 posts

256 months

Friday 20th September
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LooneyTunes said:
You could easily have the old ceiling down and in a skip single handedly in a day then only another 2 (+/- 1) man days to get that amount of insulation cut and boarded. Not a tricky weekend project if you have someone to help you?
You can buy and then sell on a plasterboard hoist for £120ish if working on your own https://www.amazon.co.uk/Drywall-Plaster-lifter-Li...

I'm currently boarding a kitchen ceiling with PIR+Plasterboard sheets and this tool makes the job fairly easy (~30kg board). I also have a garage ceiling on the to-do list.

smokey mow

1,110 posts

207 months

Friday 20th September
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Slagathore said:
Is the current ceiling very uneven? I'm not sure why the need for 25mm battens? I would have thought they'd only counter batten so they could level it? Otherwise, just fix in to the old joists?
They’ve specified it that way because it is the correct way to install a Multifoil insulation.

If you fix direct to the joist and then plasterboard straight over it’s compressed and its insulation performance is deminished.

Edit: for those suggesting PIR insulation, they have specified a mineral wool because PIR’s have not been certified as suitable for use in fire rated ceiling construction.

Edited by smokey mow on Friday 20th September 07:45

Slagathore

5,965 posts

199 months

Friday 20th September
quotequote all
smokey mow said:
They’ve specified it that way because it is the correct way to install a Multifoil insulation.

If you fix direct to the joist and then plasterboard straight over it’s compressed and its insulation performance is deminished.

Edit: for those suggesting PIR insulation, they have specified a mineral wool because PIR’s have not been certified as suitable for use in fire rated ceiling construction.

Edited by smokey mow on Friday 20th September 07:45
Ah, got you, thanks. That makes sense. I figured there must be a reason after I posted and looked at more foil types, they all had similar picture for installation.


IAN1967

256 posts

177 months

Friday 20th September
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Make sure they have allowed for jointing the new plasterboard, it's not mentioned in the description, this is needed for the fire integrity, along with fumes and draughts.

LooneyTunes

7,561 posts

165 months

Friday 20th September
quotequote all
Chris Type R said:
LooneyTunes said:
You could easily have the old ceiling down and in a skip single handedly in a day then only another 2 (+/- 1) man days to get that amount of insulation cut and boarded. Not a tricky weekend project if you have someone to help you?
You can buy and then sell on a plasterboard hoist for £120ish if working on your own https://www.amazon.co.uk/Drywall-Plaster-lifter-Li...

I'm currently boarding a kitchen ceiling with PIR+Plasterboard sheets and this tool makes the job fairly easy (~30kg board). I also have a garage ceiling on the to-do list.
Personally I wouldn't... those cheap lifters are only single cable and don't inspire much confidence vs a proper one. And its not overly hard to do a small number of sheets solo without one, just just a basic T prop.

Chris Type R

8,139 posts

256 months

Friday 20th September
quotequote all
LooneyTunes said:
Personally I wouldn't... those cheap lifters are only single cable and don't inspire much confidence vs a proper one. And its not overly hard to do a small number of sheets solo without one, just just a basic T prop.
I would struggle to lift and place a 30kg board without damaging the plasterboard - even with the use of a prop. The lifter I have makes the process massively easier and seems robust enough.

LooneyTunes

7,561 posts

165 months

Friday 20th September
quotequote all
Chris Type R said:
The lifter I have makes the process massively easier and seems robust enough.
They will do until a cable snaps (which it may never do). The proper ones have two cables for redundancy.

Obviously people risk assess in different ways, but if I had a 30kg weight above my head I wouldn't be looking for cheap, I'd be looking for safe.

For just a few boards, if they're too heavy to lift and there were no friends I could pay with beer, I'd hire a proper Levpano for a weekend.

OutInTheShed

9,324 posts

33 months

Friday 20th September
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If the current ceiling is properly fire rated, it can be a whole lot easier to rip up the floor in the room above, it then becomes trivial to put the insulation in.

Then of course you can have a nice new floor, whether it's a less offensive carpet or maybe engineered wood.
It's quite PH to say 'look at my nice garage ceiling' though.

With such a new-ish house, I would not be at all surprised to take the floor up, or the ceiling down, only to find the void is already fairly full of rockwool.
The problem is likely the void is a long way from airtight. There's perhaps a case for making a hole and having a look!

By the way, a proper PH'er shoud be concerned that sorting the insulation between the hosue and garage can make the garage very cold!


Defcon5

Original Poster:

6,303 posts

198 months

Friday 20th September
quotequote all
The garage is empty (it had my VX220 in it before the kids were born!) so minimal house disruption doing it from below rather than above, which is one of my kids bedrooms.

I have jabbed a hole in the garage ceiling and there is some rockwool in, but it’s looks more like leftovers than an actual attempt to insulate anything!

My main positive for this is that this is what was done to an identical house down the road which solved the problem. I’m obviously assuming I have the same problem here!