Beam Sizing Question

[roblenderman]

I have a 25x22 garage located on the bottom floor with the living room and attic above(no storage). Located in Seattle WA. I have a 4x12 beam running through the middle with a support post at 12 ft from the back wall and 20 ft from the back wall along the 25ft dimension. Looking to remove the support at 12ft and possibly at 20ft if possible. This would give me either a 20ft section and a 5ft section or a full 25 ft span. I am open to adding beams attached to the current beam or replacing the old one as the floor joints above sit on top of it and are not using hangers.

Need a little help is sizing as my calculations to estimate what I might need before I call in real help to actually make it happen. just trying to see if it is even possible as headroom and costs will drive the decision. Trying to use this learnframing dot com/wood-beam-calculator and i get estimates in the 20"-40" range(depending on selections) which seems high to me. Any help guiding me to a range of beam so I can find some prices would be helpful. A beam that is too big will hit my head so that could be the limiting factor.

 

[MetalBuildingFun]

Sounds to me like a proper engineer is who you should be asking these questions. Such as someone near you in your home town or the next one over?

 

[Sport]

Note: I’m not an engineer - The way it was explained to me was the greater the depth of the beam the less deflection it will have under load. Even if you sandwich multiple beams together the depth is really what matters in the end.

I just went through this with My garage and ended up with three 22” beams for a 24’ span


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[matt_i]

Sounds to me like a proper engineer is who you should be asking these questions. Such as someone near you in your home town or the next one over?

There's more to it than just sizing the beam, the beam could potentially be wider to avoid making it taller as one point of controls.

But concentrating the load into end-supports isn't trivial either, its inherently unstable and needs column bracing as well.

Angling-in or even building a large continuous beam in-place, in strips/layers is a tricky thing. It could require a slot sawed in the outside surface....

The rest of the building has to be temporarily supported while this happens.

 

[readhead]

It’s not just holding up the floor. There are multiple tributary loads running into that beam. As Matt noted the support that is in the columns will be moved to the ends which may require larger footings. This is not simple by any means but anything can be done. My favorite saying is “ the answer is money, what is the question? “.

 

[mike93lx]

Any chance the roof needs to be replaced? If so, pulling the existing roof structure off and installing clear span trusses could be an option and would give you back all the headroom that the current beam eats up.

No matter what, this is not going to be cheap.

 

[Bretny]

Live with the post. Put small shelving on it and or outlets. Make it more useful than it alreaty is because I'm sure they didnt out it there just because they had a spare one on the truck.

 

[BD1]

I have a clear span of 25' from post to post in my basement. This is for a ranch style home. My beams are W 12" X 58's.
Yes W12" beam and 58 pounds per foot .


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[66Caprice]

You can also switch over to a steel I beam instead of using wood. You can then have a beam that is not as tall. But again I am not an engineer and you should talk to one.

 

[ericlar80]

Note: I’m not an engineer - The way it was explained to me was the greater the depth of the beam the less deflection it will have under load. Even if you sandwich multiple beams together the depth is really what matters in the end.

I just went through this with My garage and ended up with three 22” beams for a 24’ span


Sent from my iPhone using Garage Journal

This is true. If you double the width of a beam, you get double the carrying strength. If you double the height of the beam, you get 8 times the carrying strength. (if all things are considered equal)

 

[scottydosnntkno]

I have a clear span of 25' from post to post in my basement. This is for a ranch style home. My beams are W 12" X 58's.
Yes W12" beam and 58 pounds per foot .


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Believe it or not, that’s a smallish beam by residential standards.

With a ranch home, your only supporting the floor and walls from one floor. With a colonial, your holding up two floors. Add in different floor heights, step downs, and cantilevers, and we often put some big beams in our houses we build. The largest so far was somewhere around a w36x256 which only spanned 24’, but had a massive (30,000+lb) roof point load coming down in the middle.

We regularly do 18x120s to span 30-35’ in a basement that’s planned to be fully finished out.

 

[BD1]

Believe it or not, that’s a smallish beam by residential standards.

With a ranch home, your only supporting the floor and walls from one floor. With a colonial, your holding up two floors. Add in different floor heights, step downs, and cantilevers, and we often put some big beams in our houses we build. The largest so far was somewhere around a w36x256 which only spanned 24’, but had a massive (30,000+lb) roof point load coming down in the middle.

We regularly do 18x120s to span 30-35’ in a basement that’s planned to be fully finished out.

I built my house 35 years ago. Back then most homes had posts every 10' or 12'. Small beams were common.
I used 5" schedule 40 pipe filled with concrete for posts and had 24" x24" x 1" baseplates.


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[cadunkle]

I've used https://webstructural.com/beam-designer.html to assist in sizing steel beams. For the span you're considering you'll want a steel beam if you care about clearance from the pad. I've used W (wide flange) beams in the past for long spans.

I suggest taking the time to learn and understand how to calculate load, deflection, and what acceptable limits are. Be sure to consider any roof or snow load if your beam supports an exterior wall or roof load.

Also don't forget the load the columns must support. You may need to pour footings depending on what you have now and the load is on each column.

 

[nadogail]

If you have to ask; is this safe enough? IMHO, It probably isn't.

I guarantee any advice from me is going to be worth exactly what you paid for it.

 

[WNYflyer]

You may be able to have steel channels designed whose backsides are slapped up against the existing wood beams and through bolted to transfer load from the wood beams to the steel channel/beams, no shoring required. Of course need to account for how the new end reactions are supported from a column and foundation perspective. And of course need to be able to physically install.

If the beam is just supporting an 11' contributing width of a 22' wide attic/living space floor subject to say 50 psf I would bet you are looking at like 2 - 12" deep steel channels.

 

[jkuro]

As WNYflyer said a Flitch plat would strengthen the existing beam but a qualified engineer would be the only one to make the call.

 

[jkuro]

Flitch Plate