Garage roof replacement: felt vs fibreglass (GRP) vs rubber (Sikalastic)

[chris1982]

We need to replace an old leaking abestos sheet roof on our garage (which is linked to the main house). I am not attempting to do this myself (as the asbestos needs to be removed professionally, access is very poor due to an extension and the garage being on the boundary to the neighbours, and having no experience with this in any case). Since the roof leaked for quite some time, at least one beam (or is it a joist?) that is currently holding up the corrugated sheets is rotten and will need to be replaced. I think for many new roofs more joists are needed too.

So we will get a roofer or builder to do the work, but everyone suggestions something else.

What are the advantages/disadvantages of
1. felt (2 or 3 layers)
2. rubber (Sikalastic)
3. fibreglass (GRP)

Since the garage is linked to the house and mainly serves as a (well, "my") man cave, ideally we get this done with some insulation. I would like it to last for some time, but I don't need a 20 year guarantee at the expense of paying twice as much when it is installed.

What type of roof would you go for?
Thanks.

 

[garyo]

I've no idea but looking forward to your replies since I need to do something similar myself.

My current view:

Felt/Bitchumin = too difficult to do well for a DIYer due to gear involved. Obviously this used to be the method of choice and is a known quantity in that respect.

Rubber: a bit expensive and can get awkward around complex detail.

Grp: seems like the new 'why wouldn't you' option to me, other than not many having been around for ten years to prove them, but boats don't seem to suffer in sunlight and get a good battering. Seems very diy friendly looking at the YouTube vids.