Cantilever (sailover) Roof Trusses

[RainDog]

What's the downside of the idea of having oversized attic trusses manufactured, say 20' trusses over a 16' span for the benefit of larger loft space and overhang for shade?

[PEG688]

  Added cost in, engineering costs,  truss materials , and soffit materails.  Also the labor to work those soffits , if your site is  very sloped hanging the fascia , covering  the soffits all that "added" over hang can be a bugger to "get to" / set -up staging to gain access to.   


  Those would be a few things to consider.

  G/L PEG


 

[rick91351]

I really don't know your lot or property nor plans but if your plain on wide eaves plan for extra fire protection.  In the event of wild fires, forest fires and grass fires wide eaves trap heat making a very effective heat sink.  In turn when it reaches the flash point your house / cabin is all but gone.  Meaning create a wider safety zone around your structure.  BLM, Forest Service and local authorities often are very willing to give you advise and pointers in these matters.  Also there are some very good PDF's on the web that I seem to have misplaced.  That said wide eaves are very effective in passive solar applications almost a have to have thing.  Just please beware of the added concerns.       

[MountainDon]

Depending on your climate you may want to take sun angles into account before ordering trusses. Too much overhang can cause winter shading of windows and eliminate any potential winter solar gain.

If there is a concern about wildfires it is imperative to keep the ground clear so fires can not creep up to the cabin/house. While big wide eves can be a problem mostly it's fire on the ground that will getcha in a wildfire. Cement board products can go a long ways in reducing fire threat. You do want to keep the flames and the hot air away from the building for certain.

[poppy]

Parks, If my review of your posts is correct, you are planning a build in NE OK.

I would suggest that you look into what passive solar designs look like in your area.

I think an oversized truss is a good idea, but a 2' overhang on each side might not be the best solar set up.  As Don said it depends on solar angles so maybe 3' on one side and 1' on the other side is better, for example.

BTW, having NE OK in your profile would be helpful for the rest of us.  So much of what we design and build is predicated on the local conditions.

[RainDog]

Once again, great answers all. Thanks a lot, guys. Guess I'll pass on the trusses. There's no clear advantage to 'em except as time savers for me and material costs would be substantially higher.

Poppy, I'll put NE OK in my profile right away. It's about time I learned to embrace being an okie, 'cause it looks like I'm here for the long haul now.

[Don_P]

I've used them several times and am doing a job with them now, 30' wide 8/12 over a 26' wide building. 2' overhangs are pretty common here. A cantilevered attic truss is a good, cost effective, way to gain room above.