[NegIQ]

Greetings! My first post....
I live in a trailer on a lake in East Texas. Extreme humidity and occasional high winds. I would like to install scissors trusses over the existing shingle roof
and put a metal roof on. My question concerns insulation...I would like to insulate fairly heavily..can I just lay fiberglass on the shingle roof or should it be between the scissors trusses, touching the metal? Also, would a vapor barrier help and where should it be installed? The trusses will not be touching the shingles except over the walls. I do not trust the old roof's ability to support any more load. Allow me to thank you, in advance, for any help you can give me in this matter.....

 

[texas115115]

Great idea

I have done this many times before, mostley in central Texas. Post a pic of your project. I usally support the new roof about 4 inchs above old roof, close in the eves, add insulation, cover and vent. All done looks great helps engery cost go down. Goodluck:thumbup:

 

[NegIQ]

Metal roof on scissors trusses over shingles

Thank you, texas 115115 for the kind response to my
first post...it is a comfort to know my ideas have been done successfully before...In your experiences with this procedure, do you simply place fiberglass insulation directly on the shingles, or elsewhere?? Also, I am concerned with condensation.. do you recommend a vapor barrier, and where would you place it??
I particularly like the Victorian peaked roof, so am planning a 10/12 top chord, with a 4/12 or so bottom chord,(enough to clear the current roof, a 3/12 pitch). This should make for a strong enough
truss. Thanks, again, for the help........:thumbsup::thumbsup::thumbsup:

 

[texas115115]

Insulation down on shingle is fine, as long as you balance your intake vents at your eves with your exaust vents. No vapor barrior needed. It will be a closed roof just like any other, except for the vents. Goodluck