a flat roof.
a flat roof.
(OP)
I have a house that is approx 988 sq ft (38x26wide) and has a flat roof. I want to change the roof of the house and plan of changing the roof with a pitch roof with bolted ceiling. My question is that what would be the size of the beam and span and what size of rafters and span I need.
Thanks for your help
aqe1
Thanks for your help
aqe1






RE: a flat roof.
Your answere depends on what material you intend to use, how many columns and with what span you got to put the trusses on them, what degree of inclination is desired for the roof and how do you want to cover the pitched roof. There are actually many choices, from a wooden truss, to tappered steel girder or steel trusses. You can do covering by means of masonary material or steel or wooden sheets. You may also use sandwich pannels for covering. Whatever your choice is, you will be needing detailed calculations and drawings that are approved by an authorised body. Just avoid instant answeres as possible loss will cost you much!
RE: a flat roof.
RE: a flat roof.
Do you have a 'collar' tie of any kind? or some element that prevents the supporting wall from being forced outwards?
Without these, if you have a significant load (snow, for example, but there's likely not much of that in Las Vegas <G>) the 2x8@16 seem light for the span.
In our environs, because of insulation requirements, a couple of inches of airspace is recommended above the insulation to allow proper ventilation.
RE: a flat roof.
Have you considered a vaulted "scissor" truss? This gives vaulting, but at slightly different slope than the exterior surface of the roof (interior is obviously shallower slope). This would be an efficient way to do what you want and the trusses could be spaced at 24" O.C.
Ron
RE: a flat roof.
mdaskilewicz@cuh2a.com
RE: a flat roof.
Unless the type of scissor truss you are thinking of is different than the one I am, the truss reactions will cause negligible outward thrust on the walls.
RE: a flat roof.
Good luck.
RE: a flat roof.
RE: a flat roof.
I am located in West Los Angeles, CA 90025
Also, I am getting tips from someone, saying, just run the
the inside partition of the house (front to rear) all the way to the roof and put double plate where the rafters of both sides of the roof will seat.
Again, I appreciate everbody's reponse, that's a big learning experience on my part.