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Roof Spar Construction for 5' TD

Posted:
Tue Feb 13, 2007 11:58 am
by Keith B
GOOD GRIEF!! Has anyone priced Oak recently. Well, I'm ready to put roof spars in I think - the walls are stood. Since my TD is 5' wide and 10' long I was going to use 1x3 oak, sandwiched together (glued) to make 1.5"x3" roof spars, sawed down to 1.5"x2.25"...but at $1.40/ft x 13 spars (on 12" center), that's like $200...so I was thinking, would a 1x3 oak glued to a 1x3 pine (studs cut down) be adequate? Still gives me the same dimensions just not 100% oak,. I do not want roof sag, but if I could do this, I'd save some coin - but I don't wanna sacrifice "doing it right either". Thoughts?!?

Posted:
Tue Feb 13, 2007 12:02 pm
by Ira
If you're laminating two 1 by 2s, you would be FINE with select pine. That would give you a 1 1/2" square spar that ain't sagging anywhere. The big issue with the pine, even the select I think, is getting straight pieces.
I used poplar, but that ain't cheap either.

Posted:
Tue Feb 13, 2007 12:06 pm
by Keith B
You're saying 100% pine 1.5"x2.25" wound be fine? Well, that's easy enough... I was going to do 50% pine/oak, same dimensions.

Posted:
Tue Feb 13, 2007 12:12 pm
by Miriam C.
Keith My husband was on top of my roof. It is made from 2x6's I cut down. I couldn't find straight 1x2's and couldn't pay for Oak. The spars end up
1" x 1 3/4" and are placed every 12". Mike weighs a good 200#. Now he wasn't jumping up and down but there was no sag in the roof. Right now I only have 1/8 Birch over.

Posted:
Tue Feb 13, 2007 12:21 pm
by Keith B
Well, if I did pine it would for sure be select clear pine, no knots, etc. My plan was 1/8" birch ceiling and 2 sheets of 1/8 birch (laminated) roof...still 12"oc.

Posted:
Tue Feb 13, 2007 12:27 pm
by Arne
'pine' is 'fine'....

Posted:
Tue Feb 13, 2007 12:33 pm
by Ira
Keith, we tend to go NUTS with this stuff.
I used poplar because I was a totally paranoid idiot. I'm STILL an idiot, but after seeing how much overbuild goes into these TDs--and hearing from dozens of guys who used pine and have 50,000 miles logged in on their TDs--it makes total sense.
All the spars are doing is tying the walls together. You're not walking on the things or anything.

Posted:
Tue Feb 13, 2007 12:42 pm
by Keith B
Agreed...and I probably, well no, I KNOW I overbuild.. so I will listen to the voices of experience. Thanks ya'll.

Posted:
Tue Feb 13, 2007 12:44 pm
by Ira
Heck, I used 1 by 2s, per Cubby plans, and those are .75 by 1.5. And the Cubby plans don't even tell you to double them up.
So laminated, I have 1.5 square spars which are solid as a ROCK.

Posted:
Tue Feb 13, 2007 12:52 pm
by IndyCubby
I used Douglas Fir. A couple 1" thick boards won't set you back very much $ and you can cut them down to make spars. It's way cheaper than oak and still a pretty dense, heavy, strong material.

Posted:
Tue Feb 13, 2007 1:48 pm
by rbeemer
Keith,
The only place you really need to us a good hardwood spar is at the hatch to support the screws for the hinge. I am not sure you need to double up all the spars, the hatch and the ceiling vent are the only ones I see. if you use 1x2" spars make sure you install then with the side grain up, in otherwords the side grain(1" width) is horizontal and the face grain(2" width) is vertical. This should give you either no sag or maybe an 1/8" sag with weight place directly in the center of the spar.

Posted:
Tue Feb 13, 2007 1:53 pm
by SmokeyBob
Keith
I user 1x2 pine gluded together. I only had a few spars that had a slight bow in it. The spars that had a bow I put them in with the bow facing up then I used a belt sander to take out the high spot. I weigh 180 lbs and I could get on top with out any problems.


Posted:
Tue Feb 13, 2007 2:13 pm
by Keith B
Well, I came across a pretty good deal, I think. Due to the # of boards I was buying, the guy sold me some VERY straight 1x4x8 pine for $2.50 and some 1x3x6 poplar at $0.90 per foot...so I have $81 invested in roof spars... I will glue the two together and since they're a little wide I have room to joint them down to make them flat should they produce any bow - and since they're a little long I should have enough to tie them together down the center too.

Posted:
Tue Feb 13, 2007 3:11 pm
by Sam I am
I used regular pine 2x2's from the local building supply place. I found a bunch of them still strapped in a bundle, and they were pretty straight! They were 8' long, so I just cut them to 5' for my tear. I think they were $1.95 each. They seem to be strong enough. I think the curved skin imparts enough rigidity and strength to the structure that I don't need hardwood spars!

Posted:
Tue Feb 13, 2007 3:24 pm
by Keith B
Very true... being shaped like an egg has LOTS of strength benefits.. however, I have about 6' of flat roof. But, I think I'm good to go now, I hope at least. I'll glue 'em up tonight and then come Friday I'll have something to work with, should luck be with me.