|02-25-19, 07:17 AM||#1|
Join Date: Dec 2012
Location: hilly, tree covered Arcadia, OK USA
Thanked 165 Times in 123 Posts
used iso panels - low cost!
I am completely re modelling the "farmhouse" on our property just NE of Oklahoma City. Wiring gone bad, old galvanlzed/corroded water pipes, roof leaking, poor insulation, lots of air leaks, etc. etc.
The roof insulation plan was to use open cell foam (R~3-4/inch) in the five inch rafter space below the roof deck. Then I wanted to put up one inch foam board sheets on the roof with 7/16 wafer board on top of that (screwed down to rafters) with a metal as the roof surface. Waterproof membrane on roof decking first.
Open cell foam was not considered on roof deck as it soaks up water like a sponge. XPS and iso boards were looked at. XPS is about R5/inch with iso at R6/inch. But the cost of iso was almost double that of XPS. The R value to cost ratio pointed me to use XPS. I had to also consider moisture trapping.
I then stumbled on an internet site that recycles iso boards. Formally, they were used for container shipping on the inside to prevent content damage. Three inches thick, 4x8 sheets and 1/4 the cost of new iso panels. Not 25% less, but 75% less! Now I can consider a thicker layer instead of one inch of foam board.
I ordered the three inch thick iso 4x8 panels as this is the thickest they offer.
This means on the roof exterior about R20 (including chip board, decking, etc). Then, on the roof deck underside, an R of about 20 (5+inches of open cell blown in foam). So a total roof R of almost R40. Yahoo!
The panels got delivered last Friday and some are beat up (mostly corner damage). These will be used on the carport roof.
My general contractor was dismayed when I discussed this plan, but now is very pleased at the cost and resultant R value.
Will keep you appraised at how it is going.
I am doing a full PEX tubing install to a central 40 port "Manablock" manifold. Plumber quotes (3) wanted almost $9K-10K to do a 2400 sq ft house - seemed like a lot. Now I have all supplies, tankless water heater, water conditioner for about $3 (raw water line to kitchen sink).
Yes, a busy job running PEX to each point of use, but ohh, the savings!
consulting on geothermal heating/cooling & rational energy use since 1990