AboutBrad Zacharia Expertise All aspects of residential Roofing. This includes shingles and flat (low slope) roofs. I have knowledge in the installation as well as the design of roofs from an engineering standpoint.
Experience I have been doing roofing for 40 years. This was my father's business and I took it over in 1980.
Publications I have written responses to artcles that I felt needed a response to and those responses have been published in roofing trade magazines.
Education/Credentials BSEE Drexel University
www.ZachariaRoofing.com
Question I own a commercial building in Westchester New York with approx. 5,000 sf of flat roof. We feel, as do several roofers, that the old roofing, of which there are at least two layers, must be removed before the new roof is put down.
Roofer #1 only wants to remove the old roofing around the 2 drains on either side of the roof in about a 15'x 15' square and a 10' wide line between the two drains. He will be using EPDM over 1/2" sheet insulation. His price is $30,000.
Roofer #2 will remove the existing roof. He will put down 2" isocyanurate insulation, then Firestone .06 fully adhered EPDM roofing. His price is $47,500.
Roofer #3 will remove the existing roof. He will then put down 1/8" Black recovery board, then install fiberglass base sheet, then cement down SBS Modifide Bitumen poly #4 rubber granulated roofing. His price is $25,000.
When asked about EPDM roofing, #3 said that there are too many problems with that kind of a roof and he will not use that material. Both #2 and #3 are larger companies and #1 a smaller one.
So my question is: Which roofing material is better? Is #3 right about all the problems with EPDM? Should I be looking for another roofer or another type of roofing material?
Answer Old roofs do not have to be ripped up unless:
1. The old roofs are so lumpy or water logged that you need to rip it all off.
2. There are so many roofs that the weight is too much but this would be unusual.
You have 3 options.
1. Old style asphalt roofs - out of date and for old-timers.
2. Modified roofs which the SBS is a type of modified.
3. EPDM.
I'll skip the asphalt roofs.
That leaves the Modifieds and EPDMs. By far the better type of roofs are roofs that are fully attached.
EPDM can be done 3 ways:
1. Laid out could with only the seams sealed. Then they lay rocks on the roof to keep the roof from blowing off. This is the cheapest and worst method since you can never see the roof and can never find a leak.
2. Mechanically attached where the roof is laid out cold, seams sealed and a bolt and plate is screwed through the roof about every 4 feet and then the bolt sealed.
3. Fully attached with glue.
The modifieds also have 3 ways all of which is fully attached:
1. Mop-down with hot asphalt. This is the old fashioned asphalt and I think it'™s crazy to use new chemically modified material with old fashioned asphalt that doesn't hold up as well as the material itself.
2. Glue-Down- It's a messy process but some roofers can't be trusted with option #3.
3. Torch-down - That's the method I prefer. Once heated you can get the material to make many shapes around things.
There is nothing wrong with EPDM roofing and some might consider it superior to modified. One advantage is that it comes in giant rolls that can cover large areas with no seams. A roll can be 20 feet by 100 feet covering 2,000 sq-ft. Modifieds come in only 100 sq-ft rolls. It's disadvantage is that it is thin and can be punctured easily by feet, tools or branches falling on the roof. But if not touched it will hold up for a long time.
EPDM can not be mixed with asphalt products. The asphalt can eat away at the material. So if you use the EPDM you have to make sure it doesn't come in contact with the old roofing. Iso board can be a separator.
How will the insulation boards be attached?
Your option #1, How will he be attaching the EPDM?
Your option #3: hopefully he is not really "cementing" the SBS down. How is he attaching the board and base sheet and SBS?
Larger roofs (commercial roofs) tend to be EPDM so it is no wonder that the smaller company is unable to do EPDM. Some manufacturers will not sell EPDM to roofers unless they get certified by the manufacturer. You can usually pick up a manufacturers warranty for an additional fee.
