Latest Discussions : Roofing & Siding


03:31PM | 03/27/04
Member Since: 03/26/04
1 lifetime posts
We have a vacation condo at the beach that is a 40 year old wood frame building. The current roof has a classic tar and gravel type roof (flat) and is about 12,000 square feet. It also experiences problems with water pooling for periods longer than 48 hours. We have received bids from roofers for both the tar and gravel type roof and for GAF Mineral Surface Ruberoid Brand Modified Bituminum roof set in hot asphalt. The roofer bidding the Ruberoid roof says it is superior to the classic tar and gravel roof and the bids are approximatley the same (around $50,000). Also, the roofer bidding the Rubberoid says that he will have to strip down the roof to the decking in only one corner of the building (where is is obviously deteriorated, where the tar and gravel roofer will strip down the entire roof to the decking. Is the Rubberoid roof really better than the tar and gravel, and is it a good idea to strip down only part of the roof to the decking?


10:13AM | 03/28/04
Member Since: 11/06/02
1278 lifetime posts
Any time you have had ponding and leaking, you need to strip the entire roof just to be able to see whayt damage has occured and repair the sheathing or more. If you go over it and trap water and mold, you cause future problems.

IMO, the single ply modified's are a poor replacement for a well done BUR. Additionally, any modified material must have some drainage slope built in. It will be in the manufacturers specs. Most BUR's should have similar drainage but can be designed to specifically handle ponding. some roofs are designed to pond water for environmental reasons.

It sounds like your roof ponds accidentally though and not by design so the modified would not be my first choice unless they included adding a slope to the roof to facilitate drainage. Again, this process normally requires stripping.

Application of modified can be done woith a smaller crew and investment in equiptment as a general rule. This would be consistant with the recommendation to go over the old without stripping. You need a large crew to remove, do structural repair, and dry in again the same section in one day to keep things dry.

My moiney is one the BUR roof for this one.

But, there is also a newer single ply product that has a forty year life expectancy. It is a rubber roofing called EPDM. See if you have anyonre in your area using it. That is now my first choice overall.

Excellence is its own reward!


12:39PM | 03/28/04

Thank you for your reply. The ponding is definitely not by design. An engineering firm did a roof survey five years ago and advised us that the ponding was accelerating the deterioration of the roofing membrane.

The roofer bidding the Rubberoid roof is going to install 1" high-density insulation and tapered insulation at the drains to create a sump to help improve drainage. He did say that he has a smaller crew "to keep costs down". I thought it was probably not a good idea to roof over moisture, and in some areas you may not be aware of moisture intrusion and deterioration until you strip off the old. By the way, we also discovered that we have true 1"x6" tongue-and-groove decking, not plywood.

The roofer bidding the 4 Ply BUR is installing 1" Polyiso with crickets to create a sump to the drains. He has also offered a second bid for an extra $40,000 to build a Polyiso insulation system that would slope the roof 1/8 inch per foot in order to positively drain the pooling water to the drains. He actually addressed your comment about "drying in" sections of the removed roof before leaving at the end of each day.


03:40PM | 03/28/04

Thanks for your response. Our roof is definitely not pooling by design. We had an engineering firm do a survey of our roof five years ago and they said that the pooling was accelerating the deterioration of the roof membrane. The roofer bidding the Rubberoid roof is installing 1" high-density insulation to entire roof deck using tapered insulation at all drains. It will have a 12 year warranty. He did say that he has a small crew "to save on costs". I had suspected that it was not proper to build over top of an existing roof as it may trap moisture that would not be evident until you stripped the roof down to the decking. By the way, we discovered that the decking is true 1"x6" tongue-and-groove, and not plywood.

The roofer who is bidding the 4 ply BUR is installing 1" PolyIso insulation with crickets to drain water to the structural deck beneath. He is also giving a separate bid on a tapered PolyIso insulation system with crickets that will taper the roof 1/8 of an inch per foot for an extra $40,000. Both have a 20 year warranty.

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