Beam Span?????

[LD1]

The pictures and diagrams paint a whole different picture.

If I understand them correctly, you are building a wall under one side of the beam that will continue half of the distance. And instead of haveing the beam divided into 3 spaces, you are wanting to have the 17' side clear-span.

If that is the case, You shouldn't need to worry about the side with the wall being built under it. EACH of the studs is going to act like a post and carry the load int the floor. So I wouldn't touch that side.

Now that we are only dealing with the 17foot section, As I currently understand it, it is all open underneath with the exception of the 1 post about 4'6" from the wall you are building and a 12'6" space on the other side all the way to the foundation wall correct?? Your goal is to eliminate that "off center" post and clear span it right???

You have a few options here. 1st woudl be to not touch the beam and just add a post @ the mid point of that 17' span. While not clearspanning, it would certainly look better than the current off-center post.

I don't currently have the load abilities of LVL's in front of be but I would think that a double 14" or 16" would certainly do it. But LVL's are pricey and you will give up head room. If you can afford the headroom, that sounds like the way to go. If the headroom is an issue, steel is about the only option you have left. You can get a beam pleanty strong enough and still not go over the 10" deapth you currently have.

 

[rtimgray]

I just taked to a building supply place and they recommended removing the old beam for the 17' span and replacing it with 2 LVL's either 14" or 16" deep. LVL's are 1.75" thick so I'll have to put a 2"x10" or a 2"x12" between them to equal my current beam width.

I'm not sure about that - looking at the LVL tables I'm looking at say that a 1.75" x 14" beam spanning 16'-6" will only support a total load of 342 lbs. Unless I'm completely misunderstanding this, is looks like maybe they were thinking you were looking for floor joists, not a beam to hold up floor joints.

Again, maybe I'm looking at the wrong tables....

 

[rtimgray]

It looks to me like it would take a 3 1/2" x 18 or a 5 1/4" x 14" or 16", depending on if its Timberstrand, Microllam or Parrallam beam.

But it looks like you could do it with that. The negative would be the loss of headroom. If you replace the existing 2x10 (9 1/4") with a 14" depth, then you're only losing about 5", which isn't too bad.

Good luck and take care.

 

[dieselscout80]

The ceiling in the basement is 8' so losing even up 8" will not be a major issue. I''' just box it with sheet rock the rest of the ceiling will still be 8'.

If I went with 3 LVL's which equal 5.25" wide what would be the best way to shorten the floor joists to allow the wider LVL beam to fit where the current 5" beam is?

 

[dieselscout80]

I just had another idea.

Would it work to use three 2"10" with two pieces of sheet steel .25"x9.25" the same length as the 2"x10" this will equal 5" like the current beam.

 

[LD1]

If I went with 3 LVL's which equal 5.25" wide what would be the best way to shorten the floor joists to allow the wider LVL beam to fit where the current 5" beam is?

BFH (Big freaking hammer)

Just kidding.

Your house is only 24' wide (perpindicular to the beam.)

According to the chart I attached, you only need to be 3-1/2" thick for a 16" beam and 5-1/4 if you choose the 14" beam.

So if you went with the 16" and baybe sandwitched them around a 2x12 with a 2x4 on top, you will be at your 5" thickness. And the 2x12 and 2x4 will add a little more strength for peice of mind.

Look at page 3, the second chart. The one for beam spans with floor joist that are not continuous. But even if they were, the results are the same. Also note that this is for 40psf live and 15psf dead loads. But then again, if you add the 2x4 and 2x12 between, you should have nothing to worry about.

oops, forgot the link http://www.parr.com/PDFs/LP LVL 1.9E.pdf

 

[dieselscout80]

We've decide to shorten the span to 13'7". I'm going to make another beam to go under the existing beam to support the span.

 

[bp fick]

We've decide to shorten the span to 13'7". I'm going to make another beam to go under the existing beam to support the span.

Do install a steel plate, as you were intimating above. Bolt it through, in a similar fashion, as you did with plywood and nails in the sandwich. A steel plate will really assist in keeping the bowed effect, sag or flex out of that beam.

13'7 is roughly the length of the average two car garage door header beam. These are sagging all over the country, when not sandwiched with steel. Ask any garage door installer. :laughing:

 

[LD1]

We've decide to shorten the span to 13'7". I'm going to make another beam to go under the existing beam to support the span.

It shouldnt take much more reinforcement if you are only lengthening the origional span by 1'1". Provided you didn't have problems with the existing beam and span of 12'6"

 

[carpenter383]

Something we did once to strenghten a beam was to cut 1/2"out of the sub floor on each side of a wall that was directly above the beam, then we sheeted the wall with osb, letting it go down and tie to the beam.
You would have to notch around your floor joists, not sure if this would be possible for you, but might be worth considering, It would definately add alot of strength. You would have to jam extention any doors in the wall, because of the extra thickness, but that's no biggie.

 

[crazyal]

Go with the LVLs. I have an 18' span under the living room. I had the choice between two 18" or 3 15" to span the distance. Headroom wasn't an issue so I went with the two 18". They are rock solid, much stronger than a 2x10. Even if you do add that support I would still spend the extra money vs. trying to put steel in between 2x10s.

Your lumber yard should have asked you for all the information and if they told you what size LVLs you needed that's what I would get and deal with any padding issues and span the full distance.

 

[dieselscout80]

Do install a steel plate, as you were intimating above. Bolt it through, in a similar fashion, as you did with plywood and nails in the sandwich. A steel plate will really assist in keeping the bowed effect, sag or flex out of that beam.

13'7 is roughly the length of the average two car garage door header beam. These are sagging all over the country, when not sandwiched with steel. Ask any garage door installer. :laughing:

How thick of steel would you use?

 

[ultrarunner]

Any updates???

 

[dieselscout80]

Any updates???

Well I'm going to for sure limit the span to 13' 7".

I'm looking at the ways to provide additional support to the existing beam.

The options are:

1. To add a beam below the existing beam made of 2"x4"x0.25" + 3"x4"x0.25" steel tube between two 2"x6" (maybe 2"x8" ripped down). The 2"x6" on the sides will replace the current ledger and keep the current beam from moving off the support beam (works for the LVL option too).

2. Cut out about 3" to 4" deep of the current beam's 1/2" plywood and insert a piece of 1/2"x3" steel with a 0.25"x5" wide steel welded to the bottom to make a upside town "T" shape (kinda like a I beam with the top flange removed). The great thing about this way is no loss of head room, but how do I cut the plywood out which in nailed in? I can think of a few ways to cut the plywood out, but all kind of scare me.

1. Use a chainsaw cutting over head and a gas chainsaw in the house not good, but if I built a depth stop and cut using the top of the bar and pulling the saw back there wouldn't be kick back issues.

2. Use a 15" circular saw and build a track so all I have to do is push in rather than hold it up and push it.

3. I think this will work best take my router (has 1/2 chuck) and use a 1/2" steel drill bit (nails would not be an issue) and build a track so all I have to do is push in rather than hold it up and push it.


No matter which option is used the existing beam will be screwed/bolt through to tighten it as show in the steel beam options.

I'm currently tearing out the bath room to prep for the beam work.

 

[Iplayfarmer]

Isn't remodeling fun!! I can empathize 100% with your situation of having to work with what's there while still trying to improve upon it.

Good luck.

 

[ultrarunner]

I would like to do the same...

I have a 4x8 wood beam under the middle of my 22 x 30 concrete garage floor. The Beam is supported by a 4x4 post every 7.5'

Removing one post would double the span to 15' and open up the 7' high crawl space under the garage and provide storage space next to my BX23...

 

[mojoinco]

Scout, given that I would rather weld above, than try to run a power tool overhead...you can see where I would go.

Or, what about running an additional 2 x 10? Since you are only adding what, less than 2 feet to the span, wouldn't that work? Offset to the long span side (12' 3")? Easier to get a sawzall in and cut the floor joists shorter. Run a temporary header and posts under the joists being cut (and screwed to hold them in place so they don't 'pop' and twist when cut).

Only my thoughts, not because I have any engineering knowledge. I suppose running an lvl the same way is similar.

 

[LD1]

I would like to do the same...

I have a 4x8 wood beam under the middle of my 22 x 30 concrete garage floor. The Beam is supported by a 4x4 post every 7.5'

Removing one post would double the span to 15' and open up the 7' high crawl space under the garage and provide storage space next to my BX23...

If you are asking for advise, more info is going to be needed.

Doubling the span is going to require a significantly stronger beam. But there is no way to figure it without knowing the loads involved.

And trying to match to something that is as strong as your current 4x8 spanning 7.5' would not be hard to do, but we need to know what type of wood the current 4x8 is in order to figure out how much load it can currently handle. It would be simple to reverse engineer from there, but their is a big difference between a white pine beam and a hardwood beam, and everything inbetween.

And it sounds like headroom is going to be an issue too. If you are wanting to maintain the current 8" of beam height, that about rules out wood all together. A steel 8" beam looks like the way to go. But just how heavy of a beam is going to depend on the above mentioned variables. Not to mention, you may have to beef up the support posts a bit if you are going to remove some of them.

 

[ultrarunner]

If you are asking for advise, more info is going to be needed.

Doubling the span is going to require a significantly stronger beam. But there is no way to figure it without knowing the loads involved.

And trying to match to something that is as strong as your current 4x8 spanning 7.5' would not be hard to do, but we need to know what type of wood the current 4x8 is in order to figure out how much load it can currently handle. It would be simple to reverse engineer from there, but their is a big difference between a white pine beam and a hardwood beam, and everything inbetween.

And it sounds like headroom is going to be an issue too. If you are wanting to maintain the current 8" of beam height, that about rules out wood all together. A steel 8" beam looks like the way to go. But just how heavy of a beam is going to depend on the above mentioned variables. Not to mention, you may have to beef up the support posts a bit if you are going to remove some of them.

My apologies to Dieselscout80... I read your post and have a similar conundrum.

Existing Beam is 4x8 #1 Doug Fir.

Ceiling height is 7' under the floor joists minus 8" under the center span 4x8 beam.

One thought is to sister steel channel with cap bolts to both sides of the 4x8... kind of a reverse Flitch Beam.

I can get two 16' lengths of 8" channel and put them back to back with the 4x8 sandwiched between. This method would not require temporary cribbing to support the floor since the original beam remains in place.

Existing beam length is 30' comprised of 2ea 15' sections...

Floor joists supporting plywood and the concrete garage floor above rest on top of the beam, 16" on center.

The former owner/builder had loaned his plan for the shop/garage and lost track of where they ended up...

Shop/Garage is 22 x 30 concrete slab supported by 2x4 cripple walls and one 4x8 beam down the center...

 

[wrath]

I'd go the steel route and build it in the basement. I'm always amazed when I see people marry more than two 2x for a beam. I always figured it was because it's cheaper to do that than to weld something up.

I never had much faith in LVLs after seeing one fall apart due to getting wet. Same for engineered joists. I'd believe in a glue laminated beam before an LVL. Something tells me in 50 years they will be bulldozing all the houses built with engineered lumber while the 1970s and older homes will still be there.