Felt Roofing Building Regulations

Dinarius

What are the recommendations/regulations for replacing felt roofing?


We are replacing the felt covering on a concrete roof that covers half/garage and half/utility-room.


Should it be two layers of felt across the entire roof?


Thanks.

D.

sydthebeat

what does the product certification and specification say??

Dinarius

I'm not the roofer, I'm the client.

A quick Google seems to suggest UK regulations of two layers of felt for unoccupied structures, such as garages, and three layers for occupied structures. e.g. a kitchen extension.

I'm simply wondering if we have similar regulations here.

I'm going to insist on two layers anyway. But, given my past experience with roofers - it seems to be very much at the cowboy end of the building trade - I am simply looking for guidance.

Thanks.

D.

sydthebeat

to be fair dinarius, we dont know what product you are talking about here... so its practically impossible to advise.

I just want to make the point that if the product isnt installed in accordance with the manufacturers specifications and design, then the warranty will be void and youll be left in limbo should you have any future problems.

Dinarius

Thanks.

Quote simply says, Black Mineral Cap Sheet torch-on membrane.

D.

sydthebeat

https://www.ikogroup.co.uk/download/57751/

assuming its something similar to this.. then at a minimum your looking at an underlay sheet and a finishing sheet.

personally i dont like torch on felt and i wouldnt specify that on any roof.

Id perfer to see a hot air welded PVC system installed.

Gumbo

Dinarius wrote: »

I'm not the roofer, I'm the client.

A quick Google seems to suggest UK regulations of two layers of felt for unoccupied structures, such as garages, and three layers for occupied structures. e.g. a kitchen extension.

I'm simply wondering if we have similar regulations here.

I'm going to insist on two layers anyway. But, given my past experience with roofers - it seems to be very much at the cowboy end of the building trade - I am simply looking for guidance.

Thanks.

D.

It still sounds like you are there when you, as the client have to specify detailed designed specification without the correct experience. Sorry if that sounds harsh.

You have to check the DoP for the product. There is no Building Regulation that specifies the exact build up, just Performance criteria. Its the Professional Designers role to turn the performance requirements into a product to suit.

I wouldn't specify Torch on Felt anymore. Fibreglass, PVC, Rubber etc

Dinarius

kceire wrote: »

I wouldn't specify Torch on Felt anymore. Fibreglass, PVC, Rubber etc

You would use any of the above to cover a concrete roof?

Secondly, if torch-on felt is being used, does that mean that the liquid sealer (can’t remember what’s it’s called) isn’t applied to the concrete first?

Many thanks.

D.

I've a torch-on felt roof. Admittedly, it's still early days (approx 2.5 years old) but it hasn't given a spot of bother and looks as new as the day it was installed (over plywood if i recall correctly, on wooden joists. It was over an extension and the one roofer did the whole job).

I think it may well come down to who you have doing it, but I was happy with the chap I got, and he seems well known around my area and competent. I would take a guess that a good installer/roofer will do a good job regardless of material they end up using. A cowboy can have the best of the best materials, and still make a mess of it.

BryanF

I specify 2 layer bitumen, have it on my extension. OP ask the builder for a 25year joint warranty with manufacturer. This assumes the roofer is trained and recommended by the manufacturer.