Replies

1. 
   ChadS. | Jun 09, 1999 12:31am | #1

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   Can you please re-post your message? It's cut off and I'm not sure of the construction?

   I can say this, I design a lot of flat/low slope roofs that put poly-iso over the deck, a recovery board (gypsum board, dens-dek or Celotex type board) and then a membrane system. The recovery board helps with the fire rating and prevents crushing of the poly-iso. If you're worried about the weight of the roofing and snow crushing the insulation board, use a higher density board.

2. 
   Vern_Schmitz | Jun 09, 1999 01:13am | #2

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   iling strips 16" O.C. 5/8" plywood and asphalt roofing. my wory is that in time the weight of the roofing, plywood and strips will squash the foam board. Has anyone any experience on this method

3. 
   Guest_ | Jun 09, 1999 01:13am | #3

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   I recently retrofitted my own roof with the following system:

   1/2" cdx over all old planks and new rafters

   2.7" rigid non-foil faced isocyanurate foam board (faced with fiberglass reinforced perforated felt paper) R20, gaps filled with gun foam (minimal expanding)

   2" wide 1/2" cdx sleepers

   5/8 T&G cdx

   6" Olympic insulated panel fasteners through the whole works and into the old rafters.

   Ice & Water shield over the whole roof (to eliminate tarps)

   Metal roofing.

   All rafter bays will be dense-packed with cellulose

   The roof feels very solid underfoot, with no odd anomalies. I wanted to use no sleepers and go with non-vented roof but inspector said I had to leave "an airspace, regardless of how big it is." If you can go non-vented you can buy iso with OSB bonded right to it. It is called "rigid nailer board," or "nail board." It is a little more expensive but fats. I received in at work by accident, a product called "vented nail board" which is perf felt iso foam of whatever thickness you like, with 1 1/2" worth of sleeper and 1/2"osb sheathing. This is all held together with hot glue, you fasten with the long screws to the framing. The 1/2" osb is glued such that it is offset the foam panel by 8" so the joints will lap each other. I paid $26.90 per sheet for the vented board with the 2" foam, but I think this is a fluke. The 2.7" board (R20) was $20 per sheet. Call a local commercial roofing supply and ask about it. They will not have a clue what you are talking about, so then try to get their main supplier. They will know what you are talking about, but they will be huge and you must understand you are nobody to them.

   Celotex makes a nail board called "nail rite" and good info can be found at their web page. A web search for "vented nail board" returned two non-substantial links thus far.

   BTW - I estimate the vented board would have saved me at least 10 hours of 2 man work versus the way I did it, but I didn't know vented nail board existed yet. The 5/8 T&G was the hardest part. I am sure you could order 5/8 osb, or 5/8 cdx on the vented board if you liked.

   If you have trouble in you search, E-mail me and I'll get the manufacturers names of both.

   The long screws cost me $129 per 1000 (cheaper than I found online), and I have 90% of a box left I'd sell cheap. The manufacturer is Olympic Manufacturing Group, their main distributor is Hodell-Natco, Olympic sent my order to them and shipped from them. The head is 1/2" diameter, very thin, and takes a #2 square drive. It is serrated on the back of the head to countersink. Cordless drills can drive 4 of these, you will need a 1/2" drill for these. The 3/8 milwaukee barely did it. If you find a 1/2" corded drill with an adjustable clutch it will be the tool to get!

   Why the long diatribe? It took me three months of part-time searching to find all these people and all this information mainly because no one along the way knew these products existed (except for the 2.7" foam - very common in commercial flat roofs)and they could get them and sell them.

   You've made me late for dinner, but I forgive you.

   E-mail if you need more.

   -Rob