Roof struncture

Originally Posted By: cnounnan
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http://www.nachi.org/bbsystem/usrimages/H/Hoot_Gibson_0481.jpg ]


[ Image: http://www.nachi.org/bbsystem/usrimages/H/Hoot_Gibson_047.jpg ]


Originally Posted By: jlybolt
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Are you asking about collar braces?


Did this roof not have any purlins? Knee walls? Any kind of support for the rafters? By looking at the picture it would seem it would need some.


Just my 2 cents


Originally Posted By: cnounnan
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None of the above.


Originally Posted By: ccoombs
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The ceiling joist can be used as collar ties. I’m not very good with conventionally framed roofs, but I do know that you can use ceiling joist in lieu of collar ties or purlins and kickers.


For your area I wouldn't expect a snow load. I would guess that the roofing is comp. shingles. However, a side note is that comp. roof should have the same loading as a typical tile because you need to assume three layers of roofing material.

The roof rafters and sheathing look new. I would ask if a permit was pulled. I don't see anything wrong with what is there.


--
Curtis

Originally Posted By: chorne
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the concern would be based on the length of the building and


the length of the rafters.


Originally Posted By: cnounnan
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Much appreciated.


Originally Posted By: jlybolt
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I agree with Carla.


You would need to look at rafter span tables to determine the max. unsupported distance the rafter can run. Snow load would also influence this. Were not designers, so if you have concerns I would list it as need further evaluation or look at roof plan if available.

Just me 2 cents


Originally Posted By: jnosworthy
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Chad,


It looks fine to me. Looks like 2 x 8’s, 24" oc, and about a 14’ to 16’ span. I’m curious about the purpose of the flat 2" x 4" 's catching the seams of the plywood roof deck. There are two reasons in my mind why this may have been done. One, is because its 24" oc and they didn’t have any H–clips for the ply. Two, they bought and installed 3/8" plywood because someone said it would be just as good, but cost less, and then they found out it was a little too “springy”.


Maybe its the photo, but I don’t see any roofing nail points or other nails penetrating this roof deck, other than the occasional 8 penny sheathing nail that missed the mark. What’s this roof covered with ??


john


Originally Posted By: mcyr
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Chad;


From the photos, it looks like the roof was constructed with two x eight's at a 4/12 pitch with a rise of 4' +/- which would dictate a span of 24 to 26'.

These spans would indicate that a knee wall at bare minimum should have been provided or a king post from ridge to a bearing point.

The ridge board appears to be a 2 x 10 and adequate.
It is assumed that since this is of conventional framing, that everything is bearing on load bearing walls. Therefore, the king post and knee wall would have played well with this design for adequate and safe loadings.

Would recommend a competent framing contractor for the area to evaluate.


Marcel


Originally Posted By: kshepard
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must be in the upper third of the roof. Joists can be used as rafter ties which tie the bottoms of rafters together.


Were the ridge or rafters sagging? If not, move on. If so recommend SE.



Kent


Originally Posted By: mcyr
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Collar ties in a low slope roof such as this one would not be recommended as much as knee walls.

Due to the low slope of the roof system and the dead load applied on it, the angular degree of the collar tie in respect with the rafters would not be as affective as having the knee wall with king post for the ridge or no king post.

The ceiling rafters in any respect will maintain and control the lateral pressures of the roof system on to the wall system.

The collar ties in low slope might not hold the tension applied to them as the compression values increase on the rafter span.

I would recommend an SE to fully advise on the proper procedure to remediate this doubt of adequacy.

Marcel