Why wood roof trusses?

totaldla wrote:
Keystone has metal roof trusses that connect to aluminum walls. ORV has wood trusses that attach to aluminum walls.

Keystone roof insulation is R16 and ORV's is R21.

Why do manufacturers still use wood in the roof?

Because wood IS cost effective.

Wood is "renewable".

Wood IS "environmentally friendly" .

Wood takes far less energy to process (IE cut down, haul and shape).

Wood "locks" in "carbon" and holds this supposed hazard until you burn it or it rots away.

Wood has a HIGHER "R" factor than metal.

Wood IS very easy to cut and shape.

Wood IS pretty darn strong.

Wood requires MINIMAL SKILL to cut and shape.

Metal, takes a lot of energy to produce, you have to dig deep into the earth to mine the ore..

Then you have to haul the ore to the surface..

Then you have to separate the ore from dirt and rock.

Processing ore to usable metals requires serious heat (energy) AND CHEMICALS (rather hazardous stuff).

Metal costs MORE than wood, takes stronger tools to cut and shape, requires GOOD SKILLED LABOR to make best use of it.

As far as "R" value difference as you noted, that comes from the kind of INSULATION AND HOW THICK the insulation is, not the type of "framing".

Some folks feel metal is superior to wood since it is well known that wood rots..

That is not really true, METAL ROTS just the same as wood.

Steel RUSTS and aluminum OXIDIZES (aluminum version of rusting), just add moisture and some salt or dissimulator metal touching it and it WILL corrode!

Too many folks get caught up with the materials hype, buy the floor plan you like and go camping..

No matter what material it is made from it WILL eventually leak..

And it is up to you the buyer/owner to do preventative maintenance to reduce the chance of leaking. Failure to maintain and any RV will ultimately fail.