Metal Roof Insulation

[Tutawl]

I have a double wide trailer that I recently had a freestanding pole barn- type metal roof put over. The trusses are approximately 1.5 ft. above original metal roof on trailers and sides come down to just past the original roof edges. From sides of new roof to trailer is about 16 in. which I am in the process of installing vented soffit. I plan to put vents in the gable ends and on the roof surface if needed. The question is when I had the metal roof installed it was not insulated. When I enclose the roof am I going to have problems with condensation on the bottom side of new roof with it enclosed like this or are the roof vents and soffit going to give it enough ventilation ? Or am I going to have to insulate the bottom of the new roof to stop condensation? P.S. I live in central Illinois if that has any bearing on your answer.

[jloomis]

[Dave in Houston]

If you are installing continuous soffit venting then I'd would go with continuous ridge venting and skip the gable vents.

Dave in Houston

[Raider Bill]

I read that if you have soffit venting then you should not have gable vents too. Something about hampering the airflow.

Next trip to Tenn I plan on putting a metal roof on the house I'm building. I was going to put 1x4 slats on top of my felt for air flow but have been told that this will invite condensation. The more I read the more confusing it gets as many now say do not vent your attic.

[jimbobmitchell]

this site has a lot of metal roffing info.

[Tutawl via HomeKB.com]

[Raider Bill]

I'm not sure. I thought having a air gap between the metal and my felt was a good idea but survey says condensation will result.

[hogheavenfarm]

I have a very similar situation. I have a truss roof placed directly on top of a short kneewall on top of a single wide trailer. The trailer roof is insulated with R11. The 'attic' is vented by a continuous ridge vent with perforated soffits. I have experienced no problems with this setup. Due to rising fuel costs this past winter, I added R38 insulation directly on top of the old trailer roof, between the studs.This was quite effective, but expensive (this is a 65 footer). I also insulated between the rafters with R21. Unnecessary I know, but I have found the heat buildup in the 'attic' was excessive, and I wanted to stop it at the source (My roof has a Southwest exposure). I used something called 'rafter-mate' , a foam channel that directs the soffit air up and out the ridge vent. So far this has worked very well.