Flat Roof - workshop

[ralral]

I have a workshop at the bottom of the garden which was not in a good condition when i bought it, and has now got worse. It is about 10X7m and has a flat roof, which leaks in a feww places. I want to cheaply (max life say 5 years) waterproof the roof. What is best - removing the old stuff and then

a. covering with bitumen
b. covering with roofing felt
c. covering with an expensive sealant
d. combination of the above

All advice gratefully received!

 

[flatman]

I would remove and replace with 2 layer torch on, if i was a quite handy diyer, I would use hot bitumen but i know what to do that way.

Evan if the old layer is dry and flat, you could overlay

 

[ralral]

Thanks for that. My gut feel was to brush off the crud on top, get some blocks of bitumen, a big boiler, and spread it liberally over the top. Roofing felt is expensive and looks like it degrades quickly with heat/cold/wind/rain.

 

[flatman]

Blocks cost £20 cover 20 sq metres avg, felt glass £20 20 sq metres, green min £20 10 sq metres, boilers £ 250 10 gall

that cheaper felt will last a good 10, 15 if laid right


It would be cheaper to use torch on, more expensive the felt, but no boiler to buy

Plus, buckets, ladle, burner, gas etc

 

[flatman]

ps, your way would crack, as it would prob be put on too thick, you would need asphelt, and you lay sheetting felt before you place the asphelt on top

 

[noseall]

Roofing felt is expensive and looks like it degrades quickly with heat/cold/wind/rain.

expensive! compared to what?

roofing felt does not degrade all that quickly.

 

[vinty]

I have a workshop at the bottom of the garden which was not in a good condition when i bought it, and has now got worse. It is about 10X7m and has a flat roof, which leaks in a feww places. I want to cheaply (max life say 5 years) waterproof the roof. What is best - removing the old stuff and then

a. covering with bitumen
b. covering with roofing felt
c. covering with an expensive sealant
d. combination of the above

All advice gratefully received!

If it is a DIY job consider using a single ply membrane, butyl rubber is suitable for beginners it can be overlaid across the top of the old roof. Just measure the length and breadth of the roof you can then have a sheet cut to the same size it is then secured with edge trim, it is as simple as that.Butyl rubber can be obtained on the internet for as little as 4 pounds a sq metre from companies like flexible linings it is also used as a pond liner.
To stop your membrane lifting you can hold it down with ballast or better still stick it down with contact adhesive.

 

[vinty]

Thanks for that. My gut feel was to brush off the crud on top, get some blocks of bitumen, a big boiler, and spread it liberally over the top. Roofing felt is expensive and looks like it degrades quickly with heat/cold/wind/rain.

If you spread hot bitty across a roof it will crack eventually because it has to be reinforced with scrim or other types of mat to stop it cracking, also there are issues with safety hot tar boilers are not for amateurs. I have advised using a single ply system because you don't have the same issues that you have using heat applied systems. If was doing it myself i would use an overlay of 4mm torch on capsheet cutting out any blisters and replacing any rotten deck first of course.