Let me start by saying that I suspect that I will need an engineers opinion, but just want to throuw this out here to see if anyone has had experience with this and wheter it is something doable at less than the national debt.
We live in the desert southwest and currently have old asphalt shingles for roofing. We would guess that they are most likely original on the house which is roughly 30 years old so are pretty much at the end of their useful life. When we replace the roof there is some structural work that I will need to do on the rafters as they mount the furnace/ac unit on the roofs here and when they built the house the rafters were not properly sized to carry the weight load. I have done some temporary repairs inside but with limited access it is hard to maneuver new timbers into the attic to double up on the original rafters, but have had some success. The roof is stick framed, no trusses anywhere in the house (1 story ranch). My plan is to have the HVAC guys come and remove the unit from the roof, it is also 30yrs old, and then remove the sheeting in that section and redo the rafters in the area where the unit sits. What we want to have installed are the tile shingles that look like regular shingles, but our concern is the weight load of these as compared to the asphalt shingles and as the whether the existing structure will support the additionl load if there is any.
Any thoughts on this would be greatly appreciated. I guess I could just trust the roofing contractor but a little information going into this I believe would allow me to make a more inteligent evaluation of their recomendations and bids as either way I we will be putting out some pretty good money. I can do any of the structural work required but I'll leave the roof installation to the professionals. Besides if it leaks I've got someone to hold responsible. haha.
Thanks for the responses.
As a roofer, if I had a customer in your situation, I would bring in a structural engineer and have him/her do a load analysis and see how many changes have to be made to your home's structure to accomodate. Roofers do not have the expertise to advise you, nor do the HVAC people. General Contractors may have, but they usually have a structural engineer on retainer for just this type of inquiry. Furthermore, you will most probably need to obtain a permit to carry out this type of work, and the permit department will usually require an architect or civil engineer to sign off on the plans submitted to obtain the permit. You are going to need more than an engineer's opinion, and unfortunately, you'll have to pay for it.