Our family is building our “in-laws” a screen house. Overall size is aprox. 12″ x 12″. The screen panels are made out of treated 2x4x8 with a 24″ knee wall and are aprox 46″ wide, 8′ tall.
Question that has come up is the top plate. Normal construction would call for two 2x4x12 positioned on the flat (3.5″ side) but my brother-in-law wants to build a “beam” out of 2x4x8’s with 1/2″ plywood in the middle (glued and nailed) and position this beam on it’s “edge (1.5 side). Although the total width will be a little wider (~4”), I’m concerned about fastening it to the corners (normally being overlapped) and being a unconventional way of building.
What are the issue with doing this? I’m an Engineer but have not found any data showing pro/con on this type of top plate. Any advice would be helpful.
Thanks.
Edited 5/14/2008 10:29 am ET by Maddog721hm
Replies
It seems ridiculous to me. What does he hope to gain?
OTOH - Sometimes people get weird ideas, and they don't want to listen to differing opinions. Since it's such a small structure, it may be best to just let him do his thing and not make a big deal over it.
Sometimes getting along is more important than being right. Especially where in-laws are involved.
A: Outlaws are wanted.
That's the issue here. He's under-employed and watches untold Home Improvement shows which in his mine makes him an expert.
Thanks for your input.
Ya could just use 4x4's and half lap them, then yer both right..LOL
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Do the panels run all the way up? If so, you need something to carry the roof load over the 46". Your BIL may be trying to create a header out of the top plate. Twp 2xs and 1/2" ply will be 3 1/2" and should match the walls.
Can't see any great harm in doing it his way, so long as the corners are adequately fastened somehow. It will be a PITA having to toenail the studs, and the nails will be more visible.
Your BIL is envisioning an eventual sag in the 46" span with just a double top plate. Turning them on edge gives a bit more strength but only in downward pressure. An easy way is to build a box, top plate on the flat, two 2xs up on edge flush with each side of the plate and another flat plate on top. No need for plywood in between. This will give more strength in both down and outward pressure. You can spike through the single top plate before building the rest. Might give you more nailing for any exterior trim around the screens. I wouldn't like a 46" span on two flat plates, either.
Beat it to fit / Paint it to match
Not clear if this screen room is attached or unattached. If attached there's likely some height limitation due to roof attachment with the house. If unattached then definitely one would like to see a 6-8" rim joist up there to carry the roof load. Also, the plate maybe should be wider than 3.5" to carry horizontal wind loads.
What is wanted is not the will to believe, but the will to find out, which is the exact opposite. --Bertrand Russell
Say since the screen room is only 12" by 12" is it just for the family dog? Inquiring minds want to know.
small dog?
The purpose of the plate is to provide a member to easily fasten and align the studs. The purpose of the double top plate is too provide enough beef for upper members to land in between the studs instead of directly on top of them.
The orientation of the studs is typically on the flat because it resists in and out movement during the construction process and is easier to fasten the studs during the framing phase. It's not an absolute necessity though. Think post and beam....no plates, yet the structure stands. Why? Because there are other engineering substitutions.
I wouldn't hesitate to orient the plates in this manner to serve a specific purpose.
The mating of the corners is not really that complicated. The simplest solution is a couple of simpson mending plates. They meet the code for connecting bearing walls if you have four nails in each wall (MI Code).
It's not "conventional" but it's not really that radical of an idea either. Theres a number of ways to make an incredibly strong connection other than simpson plates too. Staggering the ends results in great corners.
Bob's next test date: 12/10/07
What are the issue with doing this? I'm an Engineer but have not found any data showing pro/con on this type of top plate.
The issue is, what type of header are you using to support the roof over this 46" span? What size rafters are you using and what is the pitch? Is it a flat roof?
You need a header with a 46" opening no matter what way you do your top plates. You can use 1 top plate or no top plates and just frame the top with whatever header height you need.
If you figure a 2x6 header, then you can run a 12' double 2x6 with 1/2" plywood in between all the way around with no top plates.
You can probably find a Simpson connector for the ciorners.
"Put your creed in your deed." Emerson
"When asked if you can do something, tell'em "Why certainly I can", then get busy and find a way to do it." T. Roosevelt
Sphere may have been joking but I would take a serious look at it.
What joke? a 4x4 halflap is a viable option.Spheramid Enterprises Architectural Woodworks
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My bad! I guess the joke was two people being right on the same job. Tha sorta thing never happens roud here!
Yeah, LOLSpheramid Enterprises Architectural Woodworks
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