Any structural engineers in the hizzy?

M

mmmnaked

Banned
Forum Sponsor
Knocking out a 12' long supporting wall in lower floor of house, plan to replace it with post & beam setup but Im not sure if an 8x8 at 12' long will do the trixie.

If I die I plan to blame this forum.
 
mmmnaked said:
Knocking out a 12' long supporting wall in lower floor of house, plan to replace it with post & beam setup but Im not sure if an 8x8 at 12' long will do the trixie.

If I die I plan to blame this forum.
Click to expand...

Are you going for a building permit?
 
But to be serious, Id like to make it permit-proof but wont actually be submitting for a permit.
 
It depends on a few things. I don't have my book handy, or I'd give you a few "for instance"s. How long are the supported lengths on either side of the existing wall? Divide those by half, and that is part of your load. One floor or two above it? Usually you would replace it with a steel beam, or a built up beam of 2X whatevers. Nailing patterns and such are specified. A solid 8X8 is not as strong. I'll try to rrmember to look at my book when I get home.
 
Someone smart ride over to my place this weekend for a beer and burger to look at it!
 
mmmnaked said:
But to be serious, Id like to make it permit-proof but wont actually be submitting for a permit.
Click to expand...

That's the spirit!
Mike_Holmes_copy.jpg
 
First suggestion, get a permit and do it right (just because of the span etc.)...

General hack rule would be to expect 1" of wood beam "height" for every 1' of span. So you would likely need MINIMUM a sandwich of two 2X12s glued and screwed with 3/4" plywood between them to make the beam, and that may not meet code...

edit: And more importantly it does not take into consideration any additional upper floor loads.
 
Really the point of this thread was to get some contact info for someone qualified to come by and have a look (reimbursed for services, of course)

I wasn't gonna post up all the details and follow advice from GTAM directly ;)

Thanks for the responses so far though!
 
W250x33 (2.0Kpa, SRL 6.0, SFL 3.6, Roof + 1 Story with brick veneer) Make sure your bearing points go straight down to a footing.
 
Heres what you want, and you can just mail me a beer

You want an LVL (laminated veneer lumber). its a Timerstand product made by Weyerhauser.

Go to the timberstand webpage, all the snow loads, span tables, flooring tables and calculations are there on the website, the engineering is done for you. Just follow the span charts and your done.

Remember loads transfer down so the beam you install needs to be supported to the ground floor, then support under that to the basement. In a perfect world you'd punch the basement floor and put a 12"x12"x 12" footing in. (your basement floor is probably only 1-1 1/2" thick). If the load bearing wall your removing is over a steel beam in the basement that should support the loads from the beam supports.

You dont list your location, tell me aprox where you are and I'll tell you who is a retailer in your area, probably one that can assist in your learning curve.

This is the internet, non of the advice I've given is any good, if your house falls in we never spoke.

2x12's and a ply plate is for garage door headers, the ones that sag.
 
mmmnaked said:
Really the point of this thread was to get some contact info for someone qualified to come by and have a look (reimbursed for services, of course)

I wasn't gonna post up all the details and follow advice from GTAM directly ;)

Thanks for the responses so far though!
Click to expand...


An engineers visit will normally cost you at least $800 just to come out and have a look.
I can figure this out using part 9 of the building code
PM for more info
 
Thanks for the advice. Ive worked with and know what LVLs are...Im quite capable of carrying out the actual work and doing it properly, but Im not an engineer ;) so I want one to do the math to make sure :lol:

There is an aesthetic/design aspect to all of this too though. If I didnt want exposed structural features Id have this done in a jiffy with LVLs or steel dressed up in drywall ;)

Edit: and yes im carrying the load right under the floor and into footings on the foundation
 
Last edited:
Assuming Spruce,pine,fir wood, for a 12 foot span and only one floor being supported, you can get away with 5 2X8's (about 7.25" X 7.5") laminated together, assuming the supported load is only 10 feet. The supported load is half the lengths of the joists resting on the loads. i.e.if you have a room beside it that's 15 feet wide, the one on the other side better only be 5 feet wide. You can do better with 2X10's 5-ply supports about 14 feet. Solid lumber is not as strong, so you'd need bigger sizes. As suggested above, get a steel beam; W250 X 33 is probably oversize, and wrap some nice wood around it. I'd give you the name of the engineer that stamped my drawings, but he's an idiot and I had to do just as much work as if I'd never hired him.
Edit: Just looked at my drawings. The W250X33 beams I have are spanning 18 feet and are down the middle of a 35 foot space, or 17 foot supported load. I suspect you can get away with a much smaller beam. W250 X33 is 250 mm High by about 146 wide (the 33 refers to kg/m).
 
Last edited:
mmmnaked said:
Knocking out a 12' long supporting wall in lower floor of house, plan to replace it with post & beam setup but Im not sure if an 8x8 at 12' long will do the trixie.

If I die I plan to blame this forum.
Click to expand...

Doing this at my house as well. Buddy specced an 11x4" glulam beam exact same span as yours. I believe he assumed 1kpa deadload and 1.4kpa liveload. Whatever it is for attics so yours may need to be beefier since it will hold stuff above it.
 
Also even though i am a civil engineer i got one of my designer friends to come look at it... why? Because its what they do and it takes him 15 minutes to do it all in their excel spreadsheets and i'd have to whip out my calculator and notepad. I can hook you up with his contact info if you want him to check it out.


Edit:

I also hope you have consider a shoring system o keep the roof from collapsing in the mean time while u remove the existing vertical supports and install the beam.
 
Last edited:
Permits are nice but open a can of worms. On some smaller jobs the permits cost more than the work itself. What other things might get noticed that you didn't count on?
Will any electrical wiring be disturbed? Plumbing? Add for those permits.
Forum Sponsor
 
You must log in or register to reply here.
Back
Top Bottom