# Insulating garage roof- heat and sound



## --Tom-- (25 Oct 2019)

Hi, workshop build is progressing, timbers are up with a membrane cover waiting for roofer to come and tile

Thinking about insulation, what’s going to be best - celotex type up at the pitch or loft roll on top of the ceiling, or both?
Roof is looking like this:













Plan is to board over to give a ceiling to fit lights to etc. Keen for it to be warm and dry as the last workshop was damp and cold, also keen to keep as much noise in as possible to avoid disturbing neighbours.

Any thoughts gratefully received


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## samhay (25 Oct 2019)

If you don't want to use the space above the ceiling, fibreglass insulation will probably be cheaper and give better sound proofing.
You'll need a moisture barrier on the warm side.


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## MikeG. (25 Oct 2019)

To insulate both at joist level and rafter would be pointless. I would make the judgement based on whether or not you plan to use the loft space. Celotex doesn't help much with noise, but you need twice the depth of mineral wool/ fibreglass as Celotex to achieve the same level of thermal insulation.


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## Lons (25 Oct 2019)

You can buy acoustic plasterboards but they're about twice the price of standard assuming that's what you're using, Not a lot of money on a standard size workshop but you would still want insulation over for warmth though.


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## --Tom-- (25 Oct 2019)

Cheers for the thoughts, no plan to use loft space, it’s barely accessible due to the amount of struts supporting the rafters.

Sounding like mineral wool on top of the ceiling is going to be the best option for sound and warmth.

Hopefully will be finished by Christmas, apparently it’s more important that we finish the house extension first....


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## Lons (25 Oct 2019)

--Tom--":3gcl4aou said:


> apparently it’s more important that we finish the house extension first....



Partners need to get their priorities right. :wink:


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## MikeG. (25 Oct 2019)

Lons":2gmyt3bk said:


> --Tom--":2gmyt3bk said:
> 
> 
> > apparently it’s more important that we finish the house extension first....
> ...



The situation hasn't been explained clearly enough. Obviously, it is impossible to finish work on the extension without having somewhere to work on the stuff needed in the extension. This point normally sinks in when you move all of your kit into the kitchen or lounge, including a thicknesser without a dust extractor attached.


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## Lons (26 Oct 2019)

MikeG.":1uxc1s2n said:


> Lons":1uxc1s2n said:
> 
> 
> > --Tom--":1uxc1s2n said:
> ...


I did that 30+ years ago except it was the lounge - never had an issue since. :lol: :lol:


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## --Tom-- (26 Oct 2019)

Haha, I did suggest when the workshop was being demolished that everything could be moved into the house for safe keeping but was given short shrift.
Kitchen is arriving 2nd December, and I’m keen for everything in the house to be more or less done before then. 

I was getting twitchy not having any workshop space so have been doing a welding course in the evening at the local college to learn something new and do something with my hands other than type on a keyboard. Now working out where to fit a welding area into the new workshop, and wishing I’d made it bigger!


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## Lons (26 Oct 2019)

--Tom--":1ce4b77q said:


> Now working out where to fit a welding area into the new workshop, and wishing I’d made it bigger!



I have an old stick welder Tom and I'm rubbish at it tbh but occasionally it's an invaluable tool however I wouldn't let it anywhere near my workshop and if needed I use it outside, far too many sparks, same with grinding.

Just to add to my previous post, the house needed major surgery and is quite large so setting up a workshop in the lounge wasn't quite so intrusive as it sounds. Still had to overcome a bit of resistance though. :lol:


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## TFrench (4 Nov 2019)

My workshop is similar contruction. It had been plasterboarded when I got it and I added a layer of 100mm rockwool slab we had left over on a job. With the doors closed you really can't hear much from outside. The rubbish quality back door and tin roller door are the biggest "leaks" of noise. I'd second Lons's point about welding in a woodworking shop, its asking for trouble. I'm paranoid about sparks in mine.


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## HappyHacker (4 Nov 2019)

I agree with the views about welding in a wood workshop. The majority of tradesman insurance policies exclude the use of heat (including welding) without an additional premium to cover the risk and then there are all sort of conditions to be complied with. The insurance companies have evaluated the risk and obviously determined that using heat increases the number of claims

I have a friend who, many years ago, was using a blow torch to repair the lead roof on a grade 1 listed church. It caught fire inside. Fortunately it was seen before it got really bad but being a rural location took the fire brigade some time to arrive and it needed a new roof. Once he was off the roof he went straight home and read his insurance policy, he was covered  

Fire extinguishers are always a good idea even if you are not using heat.


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## --Tom-- (4 Nov 2019)

I was planning to partition off an internal “room” that can be used for welding and grinding etc to keep the mess out of the rest of the workshop and have decent extraction in. 
It would limit the size of anything I can tinker with in there but would stop showers of sparks - both from a fire risk and getting metal dust over everything.

Hoping the roof will be finished and tiled in the next fortnight. I can then move everything back in and see how much room I really have. 
It’ll have an overhang projecting into the garden to give some covered space, so could potentially get some welding curtains to keep the welding outside of needs be. 

Realising the first rule of building a workshop is “make it bigger”!

Also after this thought for the workshop, I’m asking the builder to put acoustic board for the ceilings in the extension now to help reduce the sound of rain etc on the roof.


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## MikeG. (5 Nov 2019)

--Tom--":1cfo3wnw said:


> ....... I’m asking the builder to put acoustic board for the ceilings in the extension now to help reduce the sound of rain etc on the roof.



Is the ceiling vaulted? Do you have a flat roof? If it is "no" to either of those, then you'll have insulation at ceiling level and additional sound protection will be a waste of money.


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## The Kergan (21 Nov 2019)

Celotex or Kingspan boards would be the best to use for this as they have a foil on both sides to create a double vapor barrier. Also this type of board would be double the insulation value of fibreglass insulation. 

Another thing is that vermin love to nest in fibreglass as well. 

Give BMD a try as they are cheap and I think they can deliver all over the country.
Search for BMD insulation in your search engine.


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## Rorschach (21 Nov 2019)

The Kergan":1sgubchx said:


> Celotex or Kingspan boards would be the best to use for this as they have a foil on both sides to create a double vapor barrier. Also this type of board would be double the insulation value of fibreglass insulation.
> 
> Another thing is that vermin love to nest in fibreglass as well.
> 
> ...



Unusual SPAM post, actually made an effort even though the information posted is not very accurate.


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## The Kergan (22 Nov 2019)

Rorschach":11iecpku said:


> The Kergan":11iecpku said:
> 
> 
> > Celotex or Kingspan boards would be the best to use for this as they have a foil on both sides to create a double vapor barrier. Also this type of board would be double the insulation value of fibreglass insulation.
> ...



What makes you think the information is not very accurate? 
What makes you think this is spam? 

Not a very friendly welcome is it?


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## Woody2Shoes (22 Nov 2019)

The Kergan":26v3jr7p said:


> Rorschach":26v3jr7p said:
> 
> 
> > The Kergan":26v3jr7p said:
> ...



Personally, unless I knew that the boards were extremely well installed with all edges sealed - and frankly even then - I'd always install a separate vapour check membrane on the warm side. The outer foil will simply trap any moisture that gets in past the inner foil. It's not obvious as this is your first post that you have no connection with a supplier that would seem to be nearby to you - other than as a satisfied customer I'm sure.
The worst kind of spam on the internet now is that sponsored by Putin and it is less easy to spot.
Welcome to the forum, cheers, W2S


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