EPDM membrane roofing questions


  #1  
Old 10-21-04, 05:37 AM
decolores9
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EPDM membrane roofing questions

I'm building a garage with a low slope roof (1/4" per foot). I'm planning to use a .060 EPDM membrane for the roofing. For ease of handling and cost, I'm planning to get a 7.5' x 100' roll, which will result in 2 seams perpendicular to the slope of the roof. The membrane will be fully adhered, with a termination bar and 8" lap on the house side, and rolled under the eaves on the gutter side.

Questions:

1. Manufacturer says it is OK to apply the membrane over the plywood decking, without fiberboard. Do you agree? Why or why not?

2. How should I attach the plywood? Exterior wood screws set below the plywood surface, or using the manufacturer's screws and plates? A deck will be installed on sleepers over this roof - I'm concerned that the raised height of the plates may damage the roof when the sleeper is laid over top of them.

3. Any guidance, advice or recommendations? This will be my first EPDM job. I tried to find a sub to do it, but could not find anyone interested in a job this small.

Thanks!!
 
  #2  
Old 10-21-04, 08:27 AM
J
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My experience has been with the plywood nailed down. The nails are usually 6" on center for the perimeter and 12" on center for the field. We always hammer down any "high" nails before installing the rubber. Of more concern is protection for the membrane against sleeper abrasion. Suggest gluing down strips of 1/8" asphalt impregnated hardboard. If cold, score and break...if hot cut w/knife. Please do not toe-nail the sleepers down through the rubber. The will do fine and never blow away just laying there.....railing posts and weight keep it in place.
Jim
 
  #3  
Old 10-21-04, 12:14 PM
decolores9
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Thanks for the reply.

So decking screws or drywall screws should be OK? The manufacturer recommends screws, and I'm a bit more comfortable with screws than nails.

If I understood correctly, you just glue the membrane to the plywood, without insulation? When you say to use strips of fiberboard, do you mean on top of the membrane? So, top to bottom, would it be deck, sleeper, fiberboard, membrane, plywood? Why use the fiberboard instead of a strip of EPDM?

What thickness of EPDM do you usually use in this type of situation?

Thanks again for your help!!
 
  #4  
Old 10-22-04, 03:25 AM
B
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I've specified and detailed a number of decks over EPDM roofs. What I do is (in order of materials): decking, sleepers, 3/4" blue (extruded) Styrofoam, and a strip of EPDM, all over the EPDM roof. I use extruded polystyrene as the pad because it has less water absorption than wood fiberboard or beadboard and I like that extra strip of EPDM for just a little more cheap insurance.

Another thing I do is call for the deck to be built in 6' x 6' (or so) sections so if there is ever a leak, you don't have to take the whole deck apart, you just pick up a section at a time.

BTW, I always preach to contractors to follow manufacturer's instructions (EPDM over plywood) so as to not void any warranties. Hope I helped.

Bruce

Oh, and don't forget to leave some spaces in those sleepers so water will drain off the roof!
 
  #5  
Old 10-22-04, 05:55 AM
decolores9
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Thanks for the reply.

Do you specify screws, screws with plates, or what to secure the plywood?

The manufacturer in general recommends insulation over the subtrate, but says it's OK to apply the membrane directly to plywood. Any reasons I should do the fiberboard between the membrane and the plywood anyway, even though it is not required?

The manufacturer (Firestone) also does not warrant residential installations, and only installations by certified installers. Are there any manufacturers that do warrant residential EPDM roofing and installations by non-certified installers?

Thanks.
 
  #6  
Old 10-22-04, 10:15 AM
B
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The last I checked, 6-7 years ago, manufacturers do not warrant residential even if installed by an approved applicator. As far as nailing, that's all I ever specify, but I almost always have at least 3/4" wood fiber board over the deck.

I would recommend you go to Firestone's web site and get a phone number. Ask for a technical rep and discuss your project and questions in detail. That's what I do when I have questions or need clarifications of manufacturer's literature.

Bruce
 
  #7  
Old 10-23-04, 10:22 PM
H
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Correct and Moot Point

Bruce H said:

"The last I checked, 6-7 years ago, manufacturers do not warrant residential even if installed by an approved applicator."

This is entirely TRUE and manufacturers of EDPM rubber membrane roofing products make them for COMMERCIAL application ONLY and DO NOT WARRANT any such roof applied to a residential structure.

So how and if an EDPM roof is applied to a house is MOOT since the manufacturer absolves itself of all responsibility for the product and its application.

The ONLY warranty one has when applying an EDPM 'rubber roof' on any home is the warranty the installer will provide and nothing more.

And few installers will offer ANY warranty for the product or their work when it comes to EDPM membranes on residential structures.
 
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Old 10-24-04, 06:14 AM
J
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Most mfr's have a 50 sq min for a warranty anyway. Don't use wood fiberboard as sleeper protection.....it turns to old dog food when it gets wet. Use 1/8" asphalt impregnated hardboard.....(APOC Board) it is made to protect membranes. A strip of rubber is NOT good enough. Use 60 mil rubber. Read the gluing instructions completely. Have a helper when you glue. The yellow glue is unforgiving....no second chances.
Jim
 
 

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