Remove one of two top plates to accommodate a larger header
First, as I always say, I’m a DIYer. But I’m not an idiot and I try to do my homework…
I’m enlarging an existing window opening from 5′ to 8′ on the 2nd floor. I have not consulted with an engineer but have used Forte by Weyerhauser to calculate reaction, shear, moment, and defections. With 2 ply 7.25″ LVL, tolerances are very close due to potential storage live load in the attic above (no possibility of it being finished, it is 3′ tall but has a plywood floor). I’d like to use 9.25″ LVL for a touch of overkill.
The existing wall has a double plate which seems to be going out of vogue and supposedly doesn’t serve a lot of purpose.
I”d like to cut out one of the two double plates to provide space for the taller header while keeping the top drywall return level at the same height as the other window in the room as well as not lowering the top of the window (92″ ceilings).
What do you think? Ok to chop one or two top plates? Should I use some simpson metal to tie the header to the other plate? Seems unnecessary.
Thanks!
Replies
Double top plates are not "going out of vogue".
You may not be an idiot. But you also don't have a lot of experience in load development under your belt. You may have come up with a beam solution, but no one with that experience has checked the design.
I'd suggest getting a final design on the beam before you go splitting hairs about how to install it.
You are absolutely correct about experience
I understand someone always needs to say talk to an engineer if you have doubt about your beam calculations or sizing. I don't really. I just like to be conservative and in this case, that means chopping one of two top plates to allow a large header.
You should check out Forte by Weyerhauser. It's pretty good for header calculations. I've also performed them by hand in Excel.
As compensation for my inexperience, I like to upsize or up-ply one from what I think is acceptable. I also make slightly larger than required assumptions. The energy effiency folks probably cringe when I say I upsize without cause. It's with upsizing in mind that I want to cut out one of the top plates.
2 x 7.25 2.0E LVL passes but not by a lot. 2 x 9.25 2.0E LVL passes by quite a lot, especially if you double the trimmer or jack.
Here: http://www.nrel.gov/docs/fy01osti/26449.pdf
That government advanced framing guide even suggests that I can get away with 2x8 for a roof load only. I don't know how they can even publish that without a reference to snow load but there you are.
I'm not trying to be snippy and appreciate the general warning. But I'm confident of my beam sizing. My question is about installation.
You may well be right - I don't know.
I've been doing stuff like this for about 28 years. People often come to me and ask me to size beams for them, and they often ask for advice here. My answer is that I won't design a beam unless I can see a situation for myself.
Designing the beam is only half the battle. Load development is the other half. I've found that people tend to not understand it, do it wrong, or lie about it in order to try to get the answer they want to get. So that's why I insist on checking a situation myself.
If a beam is designed right I see no reason to upsize it. If it makes you feel better, I guess it's your house. But there are so many safety factors in beam design that I don't see the need.
keith
I've done it. I don't like to split plates on a header, but with proper nailing schedule I'd rest easy. I would not cut both out. If you can't get at the plate to fasten to the header from above-figure a proper way to secure it. With the proper ridge and joists, I'd not expect it to bow the walls.
But I'm no engineer. Just a dumb carpenter.
Make sure your header calcs are right and probably figure on doubling the bucks at each end.
or
Enlarge the window opening but split it into 2 or 3 reducing the header size.
Thanks for the dumb carpenter answer
That's what I was looking for.
My calcs are conservative. I'm not cutting into the double top plate to get away with something; I'm cutting in to be conservative.
The single trimmer passes but barely so I will be doubling the trimmer (buck).
I was debating whether to use a simpson plate to tie the plate and header together (I cannot nail from above). It sounds like you think I should do that.
Thanks for the info.
keith
I changed your profile setting, you should have no problem getting all your posts to show.
Sorry, dumb carpenter and even dumber software.
We're going to the Fest this week at Taunton Headquarters. I wonder if I can find one of these "developers" (forum software manipulator). I'm sure as hell going to look. There's little real logical good verifiable realistic non BS excuse for what happens to legitimate posters while the scuzbag P O S worthless sneaky yet easy to pick out mundane ad-mongering space-pilfering spammers get through.
but I digress.
I probably should have said
that this is a single ridge gable roof on a simple two story structure. I would use an engineer for a more complex roof. In this case, the trib load is just a simple rectangle with only the attic live load. The math is quite straightforward.
I probably should have said
that this is a single ridge gable roof on a simple two story structure. I would use an engineer for a more complex roof. In this case, the trib load is just a simple rectangle with only the attic live load. The math is quite straightforward.
I probably should have said
that this is a single ridge gable roof on a simple two story structure. I would use an engineer for a more complex roof. In this case, the trib load is just a simple rectangle with only the attic live load. The math is quite straightforward.
I probably should have said
that this is a single ridge gable roof on a simple two story structure. I would use an engineer for a more complex roof. In this case, the trib load is just a simple rectangle with only the attic live load. The math is quite straightforward.
Sorry about that
Apparently I shouldn't post from my phone.
keith
Not necessarily your phone or you. This forum software is pretty user unfriendly.
4-instance-you can't post a message using the recently upgraded Internet Explorer. Yes, it's true-the most supplied and used browser don't work with this place-the older version did.............but not #10. I suppose you can blame IE, but that's hardly worth it. Make this work is what I think.