Foam Insulation Added to Roof (5/09/09)

Now that the roof has been repaired, I thought adding one inch of Extruded Styrene Foam Board (Pink Board by Owens Corning) would be a long term benefit. I happened to have (6), 4x8' sheets of this material in my garage that were left over from an insulation job I did to my sailboat.



Adding an inch of this R-5 rated Foam board, increased the insulation quality of our motorhome's roof substantially. The Tioga comes with 1.5" of Dow Blue Board installed between the framing and sandwiched between the interior panels of the roof and the outer skin, under the rubber roofing material.

Besides raising the value of insulation, from R-7.5 to R-12 overall, a touch more is added with the extra layer of 1/4" (5mm)Luan 4x8' sheeting put over it. I felt this additional layer of foam and luan would also stiffen the roof substantially.

The edges of the old roof were framed out with one inch of wood material, bonded with H.D. Liquid Nails and coated deck screws.

NOTE: Heavy Duty Liquid Nails works fine on most materials but does not work with the extruded styrene foam boards; USE THE TUB SURROUND FORMULA OF THE PRODUCT!






The foam panels are cut while down on the ground, from measurements we took up on the roof.... usually correctly :) but not always.. then brought up to the roof for a final check and trimming. (As insulation there is no problem gluing in an extra piece here and there if a mistake is made at this point.)





The adhesive was applied in larger quantities than the factory used,(I'm using 4 tubes/panel). Then the foam is applied and pressed into position. It's then lifted out for 3 minutes to allow the adhesive to flash off a bit/as per directions on the tube and the customer support hotline.





Next of course is applying the foam sheet back into position and pressed down for final bonding.