Looking for some flat roof repair/replacement help


Hi All,

I have a apt complex about 2400 sq ft of flat roof that is currently tar and gravel in the SF Bay Area.

I am getting a bunch of quotes for a re-roof or overlay all include new edge/pipe flashing

One guy is recommending to scrape off the rocks, but an upside down cap for the base, then smooth torch, then white torch for $11.6k (is this considered 3 ply?) Leaning here is the upside down cap better than the 28lb base, he says the upside down cap is 72lb making it better.

Another guy says complete tear off, 28lb base, install granulated modified bitumen for $11.9k but also raise the roof a bit to help with runoff.

Another guy is saying tear off, black base and white torch for $13.5k

Any advice on which is more durable and the better approach is appreciated. Thanks in advance…


So, first of all, A+ for creativity on the upside down cap being used as a base sheet… Assuming that he is going to mechanically fasten it, I don’t see how it’s going to give any more performance vs a base sheet, but it is certainly a more stout and durable product.

Does your current roof leak, and is it wet? If so, you should not recover it. It should be torn off. One contractors proposal indicated adding slope, is that with tapered insulation? Does the current roof pond water?

Last question, you say the roof you have is tar and gravel- is the gravel typical pea gravel or is it actually a granulated cap sheet? If it’s pea gravel, which is what I suspect it is- you can’t recover over that without some kind of recovery board- iso, Densdeck, even cheap Woodfiber.


Thanks for the reply, TJ.

It does leak, isn’t wet now but I can see the water marks on the ceiling in the unit. It is tar and pea gravel and does pool.

Not sure on the tapered insulation, would need to ask. Glad you called that out, thanks.

I as told that granulated bitumen allows the roof to last longer because it is granulated which doesn’t allow water to pool.
Also told adding a mid-ply extends the life as well.

Are those accurate statements?

Much appreciated…


Hey, thank you for the question and sharing information. For the roof replacement or repair formally there can be many things that have to be taken into considerations, and typically it can be done only by an expert itself, It would be recommended for you to go for an guide or reference as there are various companies such as Academy Roofing, Inc.; Potential Services, LLC; STB Remodeling; these all are very useful for the modification with desire. Recently, my neighbour had a replacement of their roof and sidings and they got wonderfully satisfied having it done by an expert. Hope you get it well. All the best!


You need to check in which category your flat roof repair fit then you have to decide:
Categories for me:

Temporary flat roof repair – A short term repair can be easy, quick and cost effective. The purpose is to stop the initial leak from ruining your persian carpet and Barry Manilow albums, whilst buying you some valuable time to think over, save for, or get quotes on your new flat roof, or professional repair.

Permanent flat roof repair – Permanent here meaning it will see out the remaining life of the roof covering until it is in such general overall bad condition that a new flat roof is required. Two examples of this would be good quality professional repairs or patches to an otherwise good roof. Or in some instances a ‘layer on top’ of a generally degrading existing roof, which is discussed further down.

The utter waste of time – This is the sort of repair that was never going to last because the roof is so poor, and has possibly made the life of any roofer harder should they come later to repair, or replace. In other words this will cost you more to put right, on top of the cost of the poor repair.


Well the ideas shared by others seems helpful. But if you are still confused then you should take advice from any professional person. I think he will give you best solution.