1920 flat roof repair/replace

[Tigercubrider]

a friend has a semi detached house built with a flat roof and parapet.
from memory, there is a pitched attic roof covering aprox 1/2 the area, with a door to get access to the roof.

It leaks and needs replacing. AFAIK it's asphalt

what's the best flat roofing material for this situation?

Glass fibre?
if he wanted to add external insulation is this doable with the door accessing the roof?
a building at work 20 years ago was re roofed and they seemed to add 4-6" of cork based material. would it be a celotex type material followed by the membrane?

 

[foxhole]

I would use epdm, long lasting, though don't like parapets , always a source of leaks.

 

[Nige F]

Have a look at Decothane - I have seen it's predecessor used on an existing asphalt roof

 

[Nige F]

It leaks and needs replacing. AFAIK it's asphalt

Why not post some pictures ? how high is the roof?. will it need scaffold? or skyhooks ? There is one on the forums whose knowledge of asphalt vs. tarmac is beyond reproach ( though some say belief)

 

[Elastomeric]

Asphalt is one of the easier product to overlay with the correct preparation. Decothane as suggested is good, but the proper installation of it should be 2 coats with a fleece, not easy to get right.

GRP is for boats.

EPDM will do for diy, but again, needs care taking, and preferably an OSB substrate.