I performed a job walk today to bid a job for entire home re-wire. The customers home was built in 1957, I am Looking for help with the tongue and groove ceiling. The customer is going to remove the flat roof and replace with flat roof. The customer claims ther is 3" of foam in-between the flat rood and the tongue and groove ceiling. My concerns are derating the romex, or even if romex is applicable. Any help much appreciated
tongue groove ceiling
- Thread starter Loffgren
- Start date
- Status
Does the tongue and groove ceiling have fire rated rock or plaster under it?
If there is nothing under the wood, check with building inspector before you take the job, and be sure they are not going to require rock behind the wood.
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
You have a typical deck house type roof. The rafters are exposed and there is usually an 1-1/2" T & G boards. On top of the boards is a product referred to as homasoat(sp). that is 3 or 4" thick. The shingles, if there are any, are nailed to this product.
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
I understand your concern about running the nm on the roof but if you lay the cable on the roof boards then I don't see a problem. On new construction we would usually run EMT on top of the 1-1/2" boards. The roofers would cut a groove in the homasoat and lay it down and it works just fine. That 3" or 4" of insulation is equivalent to an R-30 so I bet it is not that hot directly above the boards.
I have even drill a hole for my light and then drilled thru the homasoat right close to the top of the boards to where the wire would be accessible from the inside.
I have even drill a hole for my light and then drilled thru the homasoat right close to the top of the boards to where the wire would be accessible from the inside.
- Status