# Rafters 32" on center



## Scuba_Dave (Jan 16, 2009)

Do you have a pic of how they are bolted together ?

I think I'd add 20' cut to size in between for 16" OC


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## tpolk (Nov 7, 2009)

whats a 16/20 pitch


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## jlhaslip (Dec 31, 2009)

that's metric, I think...


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## kwikfishron (Mar 11, 2010)

32" centers on A Frames is pretty common but there Usually 4x8's with car decking on top and no sheetrock.


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## Daniel Holzman (Mar 10, 2009)

You did not indicate where you are, so it is impossible to tell what the maximum live load (read snow) is on your roof. If you are in snow country, typical live plus dead load could be as much as 40 pounds per square foot, in which case your rafters are overloaded. If you are not in snow country, the maximum live load is probably due to wind, and you would need to check with your local code enforcement official or read the code book to see what the wind load would be on the rafter.

As for your particular case, the strength of the rafters is limited either by the depth and spacing, or by the bolt job, whichever is weaker. Without a hands on inspection, it would be difficult to compute the strength of the bolt job. Even if the bolts are adequate, you are probably substantially undersized. Adding rafters between the existing rafters to make 16 inch OC is one way to go, another would be to strengthen the existing rafters by sistering new wood, or possibly by adding steel plates. You may want to consult a structural engineer, they would no doubt have some good ideas.

As to whether this is going to be a problem, if you never get any snow or wind, maybe not. If you do, the roof could collapse.


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## huai (Apr 4, 2010)

I'm in eastern pa (poconos) where snow is definitely a factor. The cabin is registered as a "recreational cabin" with the state so it doesn't have to meet residential code, but clearly I want to make it safe.

The pitch is very steep - 8 ft rise for 10 horizontal. The plywood used for sheathing is the pressed woodchip kind, not the glued layers of wood kind, so I think 32 inches is way too much of a gap


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## Daniel Holzman (Mar 10, 2009)

So you have two issues. One is that the rafters are overspanned, i.e. overloaded. Two is that the roof sheathing is overspanned. So what you do depends on whether you want to spend the time and money to fix the problems, or take the chance that a heavy snowfall will collapse the roof.


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## huai (Apr 4, 2010)

Well I knew I had a problem before I posted =/ 

Daniel, in your opinion do I have any way to backfill the missing rafters or is my only way out is to pull the roof off?


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## mark942 (Feb 2, 2008)

Scuba Dave said it. Just split the 32" to 16" add new rafters. 



Good Luck to You..............................:thumbsup:


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## huai (Apr 4, 2010)

Should I use the same rafter material (2x8s?) I have heard good things about lightweight wooden ibeams. Also - how would one go about locking both ends of the rafter in.

I can lock the lower end into the top of the wall, then bring the top of the rafter up to the central beam - then what? Notch it and move the end back and forth horizontally until it fits in?


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## mark942 (Feb 2, 2008)

Go with what you have already. Here is a link http://www.ehow.com/how_2346313_build-rafters.html In your case look more at 1 thru 3



There was a question about how the sister was bolted up. Two 1/2 x 4 inch bolts per 2x8 with a square piece of wood on either side, or better? 6 bolts? 2 bolts? 

:thumbsup:


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## kwikfishron (Mar 11, 2010)

Hey Haui, can you post some pictures? Worth a thousand words.


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## huai (Apr 4, 2010)

I'll be back working on the cottage this weekend, will post pictures then. I don't recall how it's bolted - will make sure to note that.


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## huai (Apr 4, 2010)

I bought a 20 ft 2x8 and was able to cut it down and fit it in perfectly in the middle of the 32 inch span resting one end on the ridge and the other on the top of the wall. The only question that remains is how to nail it to the sheating.

If I just let the sheating rest on top of it, the beam will prevent roof from collapsing, but wont prevent bubbling and bowing of the sheathing. However if i try to nail it from the inside, I am afraid nails will penetrate the sheating and shingles, and my roof wont be watertight.

I can get up on the roof and do the nails from that direction, but not sure how to hit the new rafters directly and i might still ahve water problems.


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## AaronB (Jan 29, 2005)

How old is this cottage?


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## huai (Apr 4, 2010)

It was built in the 60's or 70's i believe


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## AaronB (Jan 29, 2005)

And the engineering at the time isn't sufficient?


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## AaronB (Jan 29, 2005)

I had a nother post that must have been deleted.

An A frame building is usually 18/12 or 20/12 roof pitch and would not hold snow nor a person. I think this is one of the benefits of an a frame building. 


_{none of your posts have been deleted - Dave}_


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## huai (Apr 4, 2010)

Yes this is 20/12
I had to put up roof jacks and a 2x10 to work on the roof
Last time I went up during the winter, there was snow on the roof (I'd say 6 inches) compared to 3 ft on the ground.


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