Tar & Gravel vs. SBS Self Adhesive vs. APP Torch Roofing

Hi Everyone,

My 25 year Tar & Gravel roof started to leak this winter and it is time to replace it with a new roof. I live in San Francisco and have a very low slope, almost flat roof (1000 sq ft) Weather where I live is mild (mid 60’s most of the time)

Originally, I had planned to replace my old tar and gravel with a new tar and gravel. But the roofers who came out to give me a quote also came up with some modified bitumen solutions as well. My question to you is what are the advantages and disadvantages of these modified bitumen solutions when compared to good ole tar and gravel? Also, what are the pros and cons of SBS self adhseive vs APP torch on? I heard these modified bitumen roofs don’t handle ponding well (I noticed some ponding on my current roof but could this be that the roof is just in such bad shape?) I’ve listed the specs of my quotes below. Any guidance would be really appreciated.

Solution 1: 3-Ply (Torch Weld) Modified Bitumen Membrane System – (2) Ply of # 28 Type II Fiberglass Sheets (1) Ply Certainteed Flintastic GTA – FR with Coolstar – 12 yr mfg limited warranty and 10 yr warranty from roofer ~$7,500

Solution 2: 2-Ply SA (Self Adhesive) Certainteed Flintastic Modified Bitumen Membrane Roof – (1) Ply Flintlastic SA Base and (1) Ply Flintlastic SA Cap - Includes 12 yr mfg limited warranty and 5 yr warranty from roofer ~$8,000

Solution 3: 4-Ply Tar and Gravel Built Up Roof System (BUR) – (1) #28 Type II Fiberglass base sheet (3) Solid Mop # 11 Fiberglass sheets 25lbs of hot asphalt for every 100 sq ft. Cover roof with ¼â€Â

If that is a base sheet and 4 plies of tar and felt, then I would definitely go with the BUR.

The devil is in the details, though. Ask for his specs on flashings, drains, perimeter flashing, counter flashings, to start with.