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General => General Forum => Topic started by: MikeG on November 15, 2007, 08:58:42 AM

Title: questions on low slope roof
Post by: MikeG on November 15, 2007, 08:58:42 AM
I've circled the track and am back to building my own 10 x 15 micro cabin versus paying for a 12 x 16 built by a shed maker. For the sake of simplicity, I am leaning towards the shed style roof in case I wind up building it with no help.
Am looking to build without a permit, but am interested in building it soundly.

So, I have a few questions:

1) if I have a 2 x 6 x 12 spanning the 10 foot side (will that work or would it be better to go with 2 x 8s...both being standard pine lumber?), can they be secured with Simpson StrongTies or is it critical to make birdsmouth cuts?
(I've seen some of the pictures of cabins with the shed roof and can't tell how they are attached.)

Anything else you can recommend I consider?
Thanks,
MikeG
Title: Re: questions on low slope roof
Post by: glenn kangiser on November 15, 2007, 10:58:58 AM
Right offhand I'm not sure on the sizes, but the Little House plans kit

http://www.jshow.com/y2k/listings/29.html

has complete instructions on every part of the project from the foundation up including a shed roof.

Judging from the pix looks like they used 2x6's  http://www.jshow.com/y2k/listings/3.html

As you get away from the flatter pitch you would probably want to do the birdsmoouth on the lower side to keep from having a gap there.

On my garage I toe nailed with large nails, but a better way would be the Simpson connectors that have been posted here before.

(http://www.strongtie.com/graphics/products/large/H_updated.gif)

http://www.strongtie.com/products/connectors/H.html

Title: Re: questions on low slope roof
Post by: Redoverfarm on November 15, 2007, 03:08:46 PM
Mike an alternative to Simpson would be to nail scrap blocks(2X6 or what ever the demension of your wall thickness) between every other rafter (14-1/2" for 16oc or 22-1/2" for 24oc) onto your top plate.  Then nail the rafter into the blocks as well as the plate.  Hold them out flush to the outside wall and top plate to give you more surface to nail to from the rafter.  Just a thought as you always end up with scrap pieces and Simpson can get expensive.
Title: Re: questions on low slope roof
Post by: MountainDon on November 15, 2007, 03:21:38 PM
John's little house flat roof plans call for 2x8 [highlight]Doug Fir[/highlight] #2 for a 12' span, 24" OC [highlight]minimum[/highlight].
Can't see anything for 10' span.

If it was me, I'd use a 2x8 minimum for the 10' span @ 24" OC. And make that Doug Fir as he spec'd.

What about roof/ceiling insulation? Larger depth rafters will allow for more.  :-?
Title: Re: questions on low slope roof
Post by: peter nap on November 15, 2007, 04:32:57 PM
Mike, this is a span calculator Don posted a while back. Very helpful.

Unfortunately it doesn't cover 4X or larger and since I'm putting in exposed rafter/beams, I have to guesstimate.
Title: Re: questions on low slope roof
Post by: MountainDon on November 15, 2007, 05:31:02 PM
here...

http://www.awc.org/calculators/span/calc/timbercalcstyle.asp?species=Spruce-Pine-Fir&size=2x6&grade=No.+2&member=Ceiling+Joists&deflectionlimit=L%2F360&spacing=24&wet=No&incised=No&liveload=20&snowload=-1&deadload=10&submit=Calculate+Maximum+Horizontal+Span

For my money any time the calculator indicates your span to be at/near the maximum, go up a size on the joist/rafter. OMMV
Title: Re: questions on low slope roof
Post by: peter nap on November 15, 2007, 07:38:36 PM
Did I forget to put the link in? :-[

I am getting very old :'( :'( :'(
Title: Re: questions on low slope roof
Post by: MikeG on November 15, 2007, 08:52:52 PM
Thanks to all of you...I believe I will go with the 2 x 8s......and will probably go 16 inches  O.C.....with the low slope, I don't want to take too many chances...is only a few bucks more....I don't want to be frivolous, but don't want to take chances either.

Very rough figures have me drying in the 10 x 15 for right at 900 bucks.
I can live with that....and so can my bank (and by bank, I mean wife).

I'm just about ready to begin, even if the weather is cooling.
I might be able to get the skids leveled and blocked and the floor framed in the next couple weeks and then frame the walls and roof it; even if it gets cold.
Shouldn't take long too frame this small structure.

I appreciate all of your discussions...I have really enjoyed feeding on your expertise.
MikeG
Title: Re: questions on low slope roof
Post by: MountainDon on November 15, 2007, 09:09:45 PM
2x8, 16" OC makes a wise choice.  :)

Hope the construction goes smoothly. G/L and looking forward to photos.  :)