Overboarding an Asphalt Flat Roof?

[Zeberdee]

Hi Guys.

Is it ok to overboard an exisisting asphalt flat roof?

When fitting an asphalt roof what decking is used? (bearing in mind the building is a commercial kind of building and must have been built in the early 60's stroke 70's)

The roof in question has not been leaking long so unsure if decking would be rotten??

Cheers.

 

[DaMekon]

2 of the quotes i had where for fitting over existing asphalt flat roof... although the other 2 quotes were the same price, and removed it!

I decided to get it removed as at least that way you can examine the condition of the decking etc.. although, if roof has never had any leaks, you could argue that it is sound, so over fitting could be ok...

 

[Xenon]

Asphalt is usually a perfect surface to overlay. If its structurally sound, just use appropriate primer and install new membranes. If it was built in the 60's, its likely it was close boarded (planks butted together)

Its also a very good vapour barrier which you can bond insulation directly to before installing waterproofing.