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Ceiling Beams

2K views 15 replies 10 participants last post by  NoThankyou 
#1 ·
I am working on a one story house and need to remove an interior load-bearing wall. I will have to install a beam across a 20 foot span in place of the wall. How large should the beam be?
 
#2 ·
There is more to this than the size of the beam, which can be calculated from a table, the weight the existing wall was supporting was spread over a 20 foot span, you are now supporting that weight only at the ends of the beam so there has to be adequate footing under the support posts for the beam.
 
#4 ·
The supports will be the corners of two existing walls at either end of the span. The house is constructed on concrete slab. I am assuming that I will need to install additional studs in those two corners to support the weight of the beam. The only weight the beam will really be supporting is that of the ceiling joists. I can install trusses in the attic between the ceiling joists and rafters if needed. The beam will be constructed of 2"x12"x20' LVL. Just curious as to how many 2x12's would need to be laminated together in order to have adequate strength to support a 20' span. Footing support will be standard 2"x4" stud walls set on concrete at each end. I have read where you can just insert additional studs into the wall to support the beams(?)
 
#5 ·
Consult the LVL beam provider with a sketch ....

Then discuss it with a licensed builder/contractor who would be able to specify the beam size based on their experience/expertise. They would reference a table from here:
https://www.bc.com/versa-lam-lvl-span-size-chart/
This is NOT a question for internet advice or trial and error. You need an expert. :|
 
#6 ·
This is NOT a question for internet advice or trial and error. You need an expert. :|
On top of that you may also be required to take out a permit, if that is the case it is often easier to deal with the "powers that be" before starting than later.
 
#7 ·
This IS NOT a do it yourself project. Unless, you have knowledge and experience required. You post here is evidence that you do not have those qualifications.


As noted above, at a minimum you need a professional to give you the beam requirements for YOUR SPECIFIC job. This is not knowledge you can obtain from a forum.


In addition to beam and end beam support information, you need to know how to jack up(support) the ceiling while you are demolishing the wall and installing the beam.


George
 
#8 ·
Pardon if I'm insulting your intelligence, but is this truss or rafter construction?



If it is a true load bearing wall (rafter/joist), and this is not your house, IMO the owner needs to get an engineer involved or you would have liability.


I did the same thing in my house many years ago (true load bearing walls) when I was more sure of myself ;-). I used a 16" LVL & put the beam above the joists in the attic and used strapping to support them. Worked out very well.


But I'm not telling you to do that ..................
 
#9 ·
Pardon if I'm insulting your intelligence, but is this truss or rafter construction?...............
Dr Robert gave me an idea.
OK, I am speking from ignorance. I am a furniture guy and not a house construction guy so bare with me.........

Since this is going to be a major job no doubt, is it possible or even practical to get up in the attic and build a truss connecting the roof joists? After all, he would have the advantage of resting the the horizontal part of the truss (temporarily) on top of the existing wall befor removal? Cutting a hole in the ceiling would give him working space and easy access. I'm sure there are places on the web where he can get the calcultions and instructons for truss construction. He can do the design work and give it to a truss maker and see if the joints are in the proper place and if all is well or even ave a truss maker design it for him.

The nice part of being ignorant of a topic is that the ignorance allows you to be open to just about anything.
 
#10 · (Edited)
I very much doubt any reputable contractor would take this on without first consulting an engineer and they know what they are doing.

I also doubt any reputable engineer would give any advice without seeing some drawings and taking a first hand look at the situation to see if any changes have been made that are not on the drawings.

In other words this is something that a DIYer should not undertake with advice from the internet given by someone sitting at a keyboard with nothing to loose.
 
#13 ·
I am not familiar with how slab on grade is accomplished. I would think there would be thicker pours, footings, in areas of load. As stated earlier, start with an engineer or get some input with a builder or professional. It would be a bad day to do this and have the concrete fracture.

I have a neighbor that wanted to finish an attic area. To pass inspection he had to have an professional stamp it. The decision was point load was going to change/increase and piers where added in crawl space.
 
#14 · (Edited)
Exactly how it's done....

I am not familiar with how slab on grade is accomplished. I would think there would be thicker pours, footings, in areas of load. As stated earlier, start with an engineer or get some input with a builder or professional. It would be a bad day to do this and have the concrete fracture.

When my house was built I had to dig down 12" or so and make thicker pads for the load bearing columns since the slab alone would not bear the added weight. When the slab was poured, it just flowed down into the deeper pockets, all in one step. It took 5 fully loaded cement trucks for the slab, if I recall. :|
 
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#15 ·
Samandothers hit it. If the wall you are removing is a bearing wall then the slab was likely poured with a footer under where the wall was placed to carry the weight. To replace the bearing wall with a beam there would need to be added footing support built into the area beneath the slab to carry the extra load now be carried by the beam’s support posts. Initially that area of the slab was not designed to hold that extra weight.

As stated by others this is a complex project that needs to be designed by an engineer. Also, not sure about the area you live in but anywhere that I worked getting a permit to do a project like this is going to require a structural engineer’s plans to apply for said permit.
 
#16 ·
OK, Gary.

STOP, period.

You are going to need permits. To get the permit you are going to need plans signed by a structural engineer.

Without a permit and approved plans you can do it but the consequences are grave. If you are doing it for somebody else for a fee, you will be involved in a lawsuit later on. If you do it for yourself the subsequent owner will sue you eventually.

There are reasons for plans and permits and you are getting into the area of why.
 
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