Roof question

Discussion in 'Shop Talk' started by Vera, Jan 27, 2005.

  1. Vera

    Vera Well-Known Member

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    Does anybody know where I can find area-specific guidelines concerning roof construction? In particular, I need to find out how much of a roof needs to be solid, as in, spacing of skylights and such, taking into consideration that we do get some strong winds and - don't laugh - the ground moves. Also, are building codes in America regulated by county or state?
     
  2. Cosmic

    Cosmic Well-Known Member

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    Vera

    Surely you jest.

    area-specific guidelines concerning roof construction

    The world between the theory and the practical can be a deep, deep gulf. What do you really want to know????

    I will tell you this, if you go to the exact letter of the codes and bylaws and whatever, it is impossible to install a roof. Plus nobody can afford the insurance to do so. :haha:

    Your question " Also, are building codes in America regulated by county or state?"

    The stupid answer is they are National Building Codes (Twisted at all levels to mean what the vested interest wants them to be, you are subject to all interpretations at all levels as any court may decide). You figure what that means. The real answer is a form of fraud. The Fire Protection parts are part of Federal law. Just about nothing else is. Give you one example. Go get the NEC book. The electrical code and look in the front. It will say submitted to the NFPA and will be accepted without comment. In short, the one legal entity makes all the others "Legal".

    I could go into the standard rant. It is a form of con game with the issue of safety at it's core means of a reason to exist. Many side issues about how those issues are determined, including giving some economic interest an edge.

    My disclaimer: I am not anti-building codes or standards. It really has been diverted into a method of control and taxation for the normal person. You must conform to the code, you must get a permit, that keys into taxing your value and controls what the final product must be.

    Will give you this as a final thought. The shack they are building behind me is strictly by code. The entire roof structure rests on a single 2 x 4 top plate in a balloon constructed wall.

    What you probably want to know is assuming the roof structure already meets the code, can usually be dealt with by doubling up all headers or even tripling them in terms of where a roof joist is broken to install a window at width. If in doubt a sister joist as a cripple member surely will do the trick. Duh, what do you really want to do and what are you going to cut into or change?

    Vera:

    Don't depend on codes. Do your roof joist's have collar ties??? They are building these shacks all around me with special order long joists and not one collar tie. All setting on a single top plate and it is all legal. I even put collar ties in the "illegal" sheds I built out of recycled materials. :haha:

    Plus you need to know you basic roof frame style. Is it the standard flat with joists, truss members, hip, gable, gambrel, shed, etc. Some are very straight forward. Some you want to think about from many angles.

    What is your main concern???
     

  3. Vera

    Vera Well-Known Member

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    Hehehe... ok. I spent most of my life in a country where walls are 12 inch brick, ceilings and floors are reinforced concrete, roofs are strong enough to hold a sod covering if you want to put that on, and house fires are pretty much unheard of. Here, I live in a stick house that moves, with a roof that's pitifully thin, and an electric system that's just begging to go off on me. It's built to code though, and whatever I do to the roof has to be to code too because the building inspector is Mormon and I'm not.

    Now. What I'm planning to do is build an addition along the east side of the house, which will eliminate the windows in the kitchen, bathroom, laundry room and my bedroom. The bathroom will get an "external" shower with glass roof and the kitchen already has a skylight, so that's no problem, but I'll want skylights in the other rooms. That's two holes in one slope of a 40-some-foot roof, in addition to the one that's already between kitchen and dining area. The skylights can go anywhere between almost-ridge and edge of roof, if that makes a difference.

    What kind of roof it is, I can't tell you. Don't know the names in English. There are trusses (triangle) with 45-degree braces from mid-rafter to attic floor. No floor, really, just joists with drywall underneath and insulation on top, and the occasional board across the joists to make moving through the attic safer. How it's all tied together, I don't know. Hardware-wise, I mean.

    My main concerns are to 1. not do anything that'll make this stick house collapse or let the roof fall in during the first storm, and 2. make changes according to code so I don't have the building inspector make life miserable for me.
    I've dealt with the inspector before, and if he gets rubbed the wrong way or by the wrong person, he knows where to find codes that nobody ever heard of and that you violated and must correct before he gives you his ok. That's why I'm antsy about the code, not because I think it makes sense.

    So... what say you now?
     
  4. jacobs

    jacobs Well-Known Member

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    Have a group of Mormons do the work. They generally work cheaper, faster and do quality work. That should appease the inspector too.
     
  5. agmantoo

    agmantoo agmantoo Supporter

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    Vera, see if a roofing truss manufacturer in your area will give you a quote. He has a software program designed to meet the specs for your area as the trusses have to have the engineering signed and that is what the inspector uses for approval.
     
  6. rambler

    rambler Well-Known Member Supporter

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    It is very easy & simple & will not affect codes if your sky lights fit beween the rafters (trusses, it sounds like you have?). This would likely be 16" on center, so you will have about 1' wide glass. If your truss spacing is 24", so much the better.

    If you are going through an attic area, you might want to consider a tube type of skylight which often is a round tube of reflecting aluminimn that 'pipes' the sunlight from the roof down to your room ceiling.

    Attempts to cut the top cord or bottom cord of a truss can be a very difficult task, as they depend upon being one complete unit. If you would have more simple rafters then one can frame it out - with some difficulty - but a truss is something special, they are very good, but do not react well to cutting any of their members and are very difficult to bracing around a cut. Very difficult. You would need the permission & structural design from the original manufaturer, most likely. (Of course, I am speculating based on what you have said - if I misunderstood you might not even have trusses, the inspector might not care, and so on....)

    I would look very hard at fitting _between_ the trusses, which will not bother anyone, inspector or truss. :)

    --->Paul
     
  7. Cosmic

    Cosmic Well-Known Member

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    Sounds like your roof is a built up truss system.

    I did a little Goggle search and here is probably what you are up against.

    http://www.taunton.com/finehomebuilding/pages/h00045.asp

    http://www.ebuild.com/guide/resources/product-news.asp?ID=74671&catCode=10

    You can find a bunch more by Web searching on:

    roof skylights truss systems retrofitting

    Rambler could be right and they will let you drop in skinny skylights but I doubt any City / County Engineer would make it that easy. If I were in their shoes I would want some stamped remod plans. Sounds like you are planning some major changes anyway and maybe a complete tear off or major rebuild is going to be required as part of that. Looks like the fix is a convert to the normal stick built rafter type system at least in part. Think I would be talking to whoever is going to be doing your remodel and dumping the problem in their lap if possible.

    Definitely don't want to be doing this one in anything but a full legal method with all the powers that be onboard. Got to have it fully approved whatever that takes.
     
  8. agmantoo

    agmantoo agmantoo Supporter

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    Roof trusses here at set on 24" and in some cases 19.2" . Rafters made on site are set on 16".