Newbie help - making a detached single skin garage warmer

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Hi All

Just registered so I could post this, any help most appreciated. There seems to be several schools of thought on here and other sites, so I thought I would raise my own specific thread rather than guessing on how to apply to my project.

I've built a single skin block detached garage in my garden. It is 4.8m2, concrete floor over DPM and hardcore base, with a flat, ply roof, covered in industrial tarred-on felt. There is a double up-and-over door, two single double-glazed windows and double glazed personnel door. The roof overhangs the wall on one side by about 6" to protect the personnel door. This has been boarded on the underside but has a small (3mm) gap along its length where the board hasn't been quite wide enough. The roof joists are currently exposed. The bricks have been sprayed with waterproofer on the outside. The garage is within 6" of two timber/concrete board fences, barriering it on two sides. I want to be able to work in it in the colder/damper months. There will be a portable heater only, no rads. I am renovating a car so damp is a concern.

1. I plan to clad the outside in 13mm shiplap timber (mainly for aesthetics), but on doing so will create a thin gap between the timber and the blocks, say 1". Would you insert insulation in to this gap, or would it be better to insulate the inside? Would you need to shiplap all the way down the walls next to the two fences, or just the exposed sections above the fences?

2. If it is better for the insulation to be inside, which is the 'best' (reasonably cheap, spacing saving, performance) way to do this? I've seen a paint-on bitumen DPM from Wickes - would this go on the inside wall, then single battens (do they need to be treated?), then celotex (with foil front/back), then plasterboard? What depths would be suitable? Would you need to DPM on the floor where it comes in to contact with the battens/celotex/plasterboard?

3. I want to screw shelves, etc to the inside so would you use plasterboard, ply or something else stronger?

4. The airgap created by the roof overhang, would this be enough to allow the vapour to escape, or would I need to insert a vent(s) in the roof/walls?

5. I plan to install insulation in between the roof joists, could this be celotex, or is rockwool better? Would I need to board over or could I just wedge it in?

6. I plan to use a rubber floor mounted garage door strip for the bottom and a brush-type strip for the top. Is this OK or are there better ways of doing this?

7. I will be installing power/lighting cable - is this best to be done on top of the plasterboard or within the insulation, and if so where?

Many thanks for your help guys :-)
 
1) Insulate inside the brick wall.
2) Bitumen?, do the wall leak? You will get condensation that is unable to soak outwards. Is the floor wet or does it have a DPC?, just put a bit of plastic under the wood/ plasterboard. . .
3) Plasterboard is cheap (and nasty), it marks and dents. Strength of it- depends on how heavy your shelves are.
4) ?
5) If required you would need to board under it. It is best to leave an air gap right up against the roof deck, which vent to the outside. Then you insulation, then a VCL thin plastic sheet to stop moist air getting into the roof cavity.
6) Sound like a good ides, insulate the doors if they are thin steel.
7) Power, purely taste and depth of wallet. Behind the plasterboard is neater, but is much more trouble to modify

Follow the other thread further down " some thing about a cold garage"
Frank
 
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