# Garage insulation??



## Paul.J (27 Nov 2010)

I have finally decided to do some insulation in my prefab garage/workshop.
I don't want to spend a fortune on it,so was wondering if i could ask for some advice.
The garage is a double prefab concrete type with a 14' x 7' up n over steel door.I have sealed the edges off the best i can and will use 35mm Kingspan to insulate it.
Now for the rest of the garage.
I have lined the walls with 18mm shutter ply but didn't insulate behind.
Would normal loft insulation be ok to do this.
The roof is again boarded 18mm shutter ply and felted.
Would the loft insulation be ok again.
Thank you. 
Edit-:
Forgot to say as i was rushing when i put the post on,is that two of the wall have full length sheds built onto them,so i really only have one outside wall. 
So would would those two inner walls be worth insulating :?: :?:


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## joiner_sim (27 Nov 2010)

This isn't really an answer to your question, but thought I'd add this link to the discussion, as this is a product I have started working with now in my new job at a timber framed insulation board manufacturers. JabLite, it's polystrene insulation http://www.jablite.co.uk/ it comes in various thicknesses, and cuts really easy on a table saw, just be careful if cutting that the polystrene doesn't bind with the blade, make sure the offcut is removed as soon as its cut.


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## Paul.J (27 Nov 2010)

Thanks Simon,but i was looking for something that i could sort of stuff behind the ply on the side walls,save me taking it all off,and the roof space would need loads of cutting as the spacings are all different sizes.
Does this Jablite make as much mess as normal polystyrene :?: 
I have cut ps on a tablesaw and you are right about the binding,best if two are doing it,one pulling off.
How is the new job going :?:


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## joiner_sim (27 Nov 2010)

The jablite get extracted quite well, you just end up with a small amount of mess, nothing more than what you'd expect from cutting timber. Unless you break it yourself, then it gets messy!
The new job is going alright, been working on the panel saw, radial arm saw and spindle moulder mainly so far. Done a small amount of hand work, but can't expect too much from a machinist's postion.


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## Paul.J (27 Nov 2010)

Thanks Simon.
Sounds like you've settled in well.
Just be careful.


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## Jacob (27 Nov 2010)

Kingspan etc cuts very easily with a hand saw (say a 22" panel saw) without generating dust like a TS. If you are making it a close fit trimming the edges with a Surform rasp is good.
NB it does need to be a good fit with air gaps sealed with mastic or foil tape - otherwise on a windy day cold air can bypass the insulation completely. So I'd rip out your boards and start again, making every bit of insulation fit tight.

And yes insulate the party walls too - unless you are certain that the next door internal temperatures will always be same as or higher than your own target.
For that matter insulate your own internal partitions too, if there are any.


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## Blister (27 Nov 2010)

Paul

I did mine like this :-

https://www.ukworkshop.co.uk/forums/what ... ght=garage

and insulated inside the roof with polystyrene sheets as I could bend them without snapping 

:lol:


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## Lons (28 Nov 2010)

Jacob":3emjy6pt said:


> Kingspan etc cuts very easily with a hand saw (say a 22" panel saw) without generating dust like a TS. If you are making it a close fit trimming the edges with a Surform rasp is good.



Even easier is with a long metal straightedge and a sharp knife (old carving knife is ideal).
Just score cut it a couple of times and snap it. ( Bit like cutting plasterboard - have to cut the covering reverse side as well). Very quick and almost no mess.

I put several hundred 50mm sheets of celotex into a stable conversion a few years ago and have recently used the same method on my own extension - foolproof!

If you cut it slightly too big by mistake you can rectify to a tight fit by running the knife in situ down the offending side.

cheers

bob


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## Paul.J (28 Nov 2010)

Thanks all  
Allen that is exactly what i done to the walls in my garage,except for the insulation.
I have ordered the 35mm KS for the door,so hopefully that will arrive tomorrow.
I will use the handsaw to cut and fit it.
Any info re the wall/cealing insulation apart from using KS.Would the rockwool type stuff do.I see B&Q are doing it for a £1 a roll.


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## Gary (28 Nov 2010)

Wickes also have a deal on.

Buy 1 get 3 free, if B&Q don't have the stuff you need.


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## Jacob (28 Nov 2010)

casting my mind back several years - yes Lons is right, use a knife. Score one side deep, snap, slice through the paper on the back.
Good excuse for buying a Mora craft knife. I just bought one, very handy and comes with a practical sheath to fit on your belt. Reminds me of when I was in the Peewit patrol!


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## studders (28 Nov 2010)

Be aware... the cheap rockwool from the sheds is a nightmare to fit, like trying to knit mist...... says he who did his a few months back. It just disintegrates when you unroll it. That said, it does seem to have done the job though I'm not in a rush to repeat the experience.


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## barkwindjammer (28 Nov 2010)

Polystyrenyreneyereen beads, has anyone tried this method ?


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## Gary (29 Nov 2010)

barkwindjammer":1l7fwueb said:


> Polystyrenyreneyereen beads, has anyone tried this method ?



Be fun trying to line the walls with them. :lol:


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## Dibs-h (29 Nov 2010)

Gary":27pgg9x7 said:


> barkwindjammer":27pgg9x7 said:
> 
> 
> > Polystyrenyreneyereen beads, has anyone tried this method ?
> ...



Even funnier drilling holes in the wall to hang stuff. :wink:


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## Lee Brubaker (2 Dec 2010)

Your gonna laff but back in 1959 I built a double garage & as money was pretty tight I insulated the walls & the underside of the roof by stapling on newspapers between the wall studs & rafters. I had a small gas fired radiant heater & it had no trouble keeping it toasty warm. I also made my overhead door framing the panels with cedar & sheeting them on both sides with 6mm plywood.
We moved in 1963 first to Vancouver to Toronto then back to Vancouver & finally to Edmonton in 1974. 
When driving to Edmonton from Vancouver we routed through Calgary & took a drive past the old house. Despite now being 15 years old I was a little amazed to see my homemade overhead garage door still in use.

Lee


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