What is the best way to insulate a flat garage roof, I have a tin roof on top of roof timbers?

Question

The roof slopes around 10 degrees, and is tin built on standard roofing timbers which are around 150 mm deep.

Answer 1

Two choices for you
1. and the best contact a sprayfoam contractor and have it sprayed with a 2lb closed cell foam excellent results with no condensation problems Be sure to cover any foam product with drywall or some kind of 10 min fire barrier

2 insulate with batt insulation Roxal or an equal be sure that you have at least 1" of air space between tin and insulation modify roof so that air can flow in from lower edge of roof and out the top edge this can be done with different types of flashings. Cover the warm side of the insulation with heavy gauge poly being sure to seal ALL holes in poly then cover with something to make it pretty

Answer 2

Depending on your climate, a flat roof is usually a bad idea. The aluminum paint works well. There is also a rubber membrane that has adhesive on one side and can be put down on the roof. It's called ice and water shield. If a small hole should develop in it from a nail or something, it is self-sealing. You might want to check the wood underneath before you start any repairs just in case anything needs to be replaced first.

Answer 3

You can buy 100mm cavity wall insulation made by Isowool, from Wicks and cut it with a sharp kitchen knife to fit between the timbers, but cut it a little bit bigger than the gap between the timbers and just push it into place. You can then fit plasterboard to cover the insulation, by using plasterboard screws.
Remember to make sure that you don't buy the rolls of insulation, because its better to work with the slabs.
You have to use a mask, safety goggles and a protective overall which is cheaper from B&Q.

Answer 4

Have you considered putting another roof on top of the existing roof, with the cavity between, will reduce condensation, off the internet you can buy 10 by 4 galvanised ,plastic coated box profile sheets, which are really good, no finish required,lay some 4by 1 on top off your existing roof and secure to existing joists, then using the correct bolts secure new sheets to the 4by 1

Answer 5

I my opinion the best thing for you situation is Core-bond insulation, It is a sprayed on product that goes on about 2 in thick and has a great R factor plus it will really stiffen up the roof. It's done by pros's for about $2 a square foot

Answer 6

Certainly, initially all seams should be well caulked, then purchase construction grade FOAM insulating sheet material, usually found in 4 x 8 sheet stock. It varies in thickness but for your purpose 2 or 3 inches is sufficient. It can be adhered with construction grade adhesives, and then likely you might consider aesthetics and cover the rafters beneath with some other sheet stock, IE: Drywall.

Answer 7

plastic sheeting,Rockwool and plywood .

Firstly put plastic sheeting on the underside of the tin roof, then the rockwool between the roof timbers. Hold it all in place by plywood sheeting.

The thicker the rockwool, the better the heat and sound insulation. The plastic is to keep the rockwool dry.

Hope that helps and good luck.

Answer 8

You can get sheeting that consists of a top and bottom sheet with insulation foam in the middle, it comes in different thicknesses.

Answer 9

use cavity batts glue with waterproff silcone to under side of tin,or if you are going to under board timbers to make a ceiling use 150mm fibreglass wear overalls dust mask goggles the board underside

Answer 10

with it being covered in tin its going to develop a lot of condensation,your best choice would be dry-therm cavity fill slabs 600x1200 these have a waterproof ingredient's.they would last longer under the conditions.would of been better to under felt first.