1st time visitor/poster – congratulations to all on an amazing forum!
I have a 16’X16′ flat roof coming off a 14/12 gable. The roof is shot and I would like to give it some slope and some insulation. It is 24′ in air and there is no traffic on it and I’d like to leave it close to flat – so I am thinking of having insulation cut from 1″ ( over eave line ) to 5″ at a new ridge line getting almost a 1/2″ in 12″ slope plus some insulation ( 1″ = R4 ) What do I cover this w/ EPDM, PVC w/ seems to weld? Your ideas & input will be most appreciated John
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John,
I would put EPDM on it. The rubber is glued to fiber board that is screwed to the deck, so a bit of insulation is automatic. The board can be purchased to give some slope. I've never installed that (board for slope), but I think the price goes up quite a bit over just flat board.
Another day, another tool.
Roofing wholesalers have pitched insulation. Gold Bond was what I used to use.
EPDM is far better than PVC.
Excellence is its own reward!
"The first rule is to keep an untroubled spirit.
The second is to look things in the face and know them for what they are."
--Marcus Aurelius
I'll also vote for EPDM. Single sheet, no seams to mess with.
If you need more R-value, look at tapered sheets of polyisocyanate insulation. R7.2 per inch.
John
Welcome
The insulation Mogo discribes is the very best in my opinion. I've always used EPDM torchdown. Just be sure to have a fire extinguisher on the roof at all times. I dont recommend the glue down at all. Its not as perminent IMHO from experiance.
Be well
Namaste
Andy
It's not who's right, it's who's left ~ http://CLIFFORDRENOVATIONS.COM
Andy, You got your wires crossed on this one. You're working too hard on the TV show, the building committee and the concrete basement.
EPDM is not a torchdown. The other single ply membrane you are thinking of is called modified bitumen. It is applied with a torch to melt the modified asphalt layer and seal the seams whild adhering to the substrate. It comes in rolls about 39 inches wide and is nicknamed rubber roofing but the true rubber is the EPDM. It is twelve feet wide in the roll and it generally glues down with contact cement on residential applications.
The EPDM is far better then the modified, IMO. ten year product vs. a fourty year product. fewer seams to fail too..
Excellence is its own reward!
"The first rule is to keep an untroubled spirit.
The second is to look things in the face and know them for what they are."
--Marcus Aurelius
have to go with the modified myself.much better than a glued down inner tube
Much better by what criteria? Durability? Ease of installation? Safety of installation? Compatibility with flashing? Cost? Resistance to sunshine? Resistance to air pollution? Resistance to cracks? Resistance to punctures? Resistance to seam failures? Smell? Embodied energy? Use of renewable resources? Something else?
I don't see where you can call it better when the warrantee is a fourth as long.
It's basicly a cheap version af a DIY built up roof,IMO
The only way I see getting the impression that it's better is that it is thicker. Over time, thatt thickness works against it in shrinkage and checking..
Excellence is its own reward!
"The first rule is to keep an untroubled spirit.
The second is to look things in the face and know them for what they are."
--Marcus Aurelius
Piffin,
Has mrmojo been around before? I see a number of posts from him today that look like their only aim was to be contentious.
There's a word tickling my memory. I can't quite get it, but it's associated somehow with the three billy goats gruff.
Piff
Yeh..I got my rubbers mixed up.lol
I used my torch the other day to melt the snow and ice in my driveway. Excellent!
Be a torch
Namaste'
AndyYou don’t complete your inner work before you do your outer work. Nor do you say, "Well, the hell with the inner work: I’ll go do the outer work because it’s so important and pressing." That’s not conscious either. The conscious thing is the simultaneous doing of both. "Ram Dass"http://CLIFFORDRENOVATIONS.COM
many thanks for your feedback
FYI - EPDM comes in different thicknesses - commonly 30, 45, 60mil (I have heard of 90 mil too). 45 is 'standard where I am at - 60 is better performance. 30 might work for you.
The fiberboard is a good idea too. I have seen a couple installations of epdm over iso (polyisocyanurate), where after a guy walked across it with a small wedge shaped rock in his shoe, that it punctured the membrane. This (as I was told by the product rep) was because the iso doesn't have as high of a density as fiberboard would; therefore more readily allowing a puncture. Maybe think about tapered iso with fiberboard on top. Also, make sure to check out the mnf warranty info about applying over certain substrates - it usually will give you a clue about what is appropriate. Another option is using extruded polystyrene with the fiberboard, it should save you a few bucks.
Just something to keep in mind.
Just so everyone is aware, the R value for iso can range from 6 (1" thick) to 14.3 (2" thick) - so there is not a linear relationship between R value and thickness (from Celotex brochure). Extruded polystyrene is usually considered to be around R5 to R5.5, depending on densities (Styrofoam from Dow). There are also new government requirements concerning the blowing agents used in iso (to expand the foam during curing) that may affect the published R values of iso in the next few years.