LVL span question

[STINEY]

Long story short - I have a 16'x22' room with the overhead joices running parrellel to the 16' end. Joices are non dimensional actual 2x10 rough sawn.

The joices have become "springy", its an old building approx 150 years old.

I want to brace these joices up with some 2x10 dimensional LVL beams running down the middle of the 16' span, and supported on the ends with solid piers.

How many 2x10 LVLs would I need to sandwich together to accomplish this?

 

[ishiboo]

I ran into this with my 100 year old home. Before you perform a repair, I would verify that you don't have substantial sag as well. It may be best to remove the whole floor and replace with clear span TGIs which will easily do that distance.

I did this in my kitchen - it was 2x8s spanning 18' and they sagged almost 2" in the center and had a ton of bounce.

In the living room, I jacked and put a center beam... and I wish I would have done the same as I had done in the kitchen.

 

[NUTTSGT]

If you're going to buy them local, stop at Carter and talk to Brad.

 

[ejkuhl]

For a general idea check out page 7 of this pdf http://www.dickslumber.com/lumber_wood/documents/Microllam.pdf

 

[STINEY]

I ran into this with my 100 year old home. Before you perform a repair, I would verify that you don't have substantial sag as well. It may be best to remove the whole floor and replace with clear span TGIs which will easily do that distance.

I did this in my kitchen - it was 2x8s spanning 18' and they sagged almost 2" in the center and had a ton of bounce.

In the living room, I jacked and put a center beam... and I wish I would have done the same as I had done in the kitchen.

You are right, I already took out at least that much sag. Now I want to clear the space underneath of the center supports.

May I ask why you wish you had done the same as your kitchen? Did it not cure the bounce?

If you're going to buy them local, stop at Carter and talk to Brad.

Excellent advice. I have not seen Brad for a little while anyways. Last I talked to him he was looking for a cheap VW motor....

 

[STINEY]

For a general idea check out page 7 of this pdf http://www.dickslumber.com/lumber_wood/documents/Microllam.pdf

The chart on page 7 is useful.

However, it seems to be calling for a single beam 5.25"x18" - which is fine, actually overkill because the table only goes to a 20' width span, and I'm only at 16'

I have room on my piers for more than one beam.....could I go with a 5.25"x9.25" and use 3 or 4 of them?

I'd really-really-really like to stay in the 10" or less for headroom reasons.

 

[ejkuhl]

The chart on page 7 is useful.

However, it seems to be calling for a single beam 5.25"x18" - which is fine, actually overkill because the table only goes to a 20' width span, and I'm only at 16'

I have room on my piers for more than one beam.....could I go with a 5.25"x9.25" and use 3 or 4 of them?

I'd really-really-really like to stay in the 10" or less for headroom reasons.

I know page 7 does not have your exact figures, but i figured it would give you a start.

If you look at page 9 of the same document, it does show that the capable loading of the 5.25x18 is about 3 to 4 times that of the 5.25x9.5.

I would think 2 or 3 of the 9.5 would be sufficient. It is currently supporting itself and you are just looking for a stiffener and taking the sag out.

 

[STINEY]

That is great info.....exactly what I needed to know.

Thanks guys! I'll run this idea by Brad and get them ordered.

 

[ejkuhl]

It is also possible to jack the floor up temporarily to get the sag out and laminate new 2x10s or even 1.5 inch LVLs to the side of each joist or every other joist. Then no beam and loss of headroom.

I have fixed sagging floors in old houses both ways(doubling floor joists and with beams at center span)

 

[Trey T]

I believe you wouldn't need LVL to accomplish it, just regular lumber from HD or Lowe's. If the overhead floor held up for 150 yrs, it's strong enough but just bouncy and make it discomforting. Therefore, there's not a lot of force to be supported.

From my quick research, the modulus (strength of material) of LVL is about 30% stronger than typical wood beam you see in HD. The weight/linear-ft is only about 5 lbs lighter.

...
The joices have become "springy", its an old building approx 150 years old.

I want to brace these joices up with some 2x10 dimensional LVL beams running down the middle of the 16' span, and supported on the ends with solid piers.

How many 2x10 LVLs would I need to sandwich together to accomplish this?

 

[kert]

Long story short - I have a 16'x22' room with the overhead joices running parrellel to the 16' end. Joices are non dimensional actual 2x10 rough sawn.

The joices have become "springy", its an old building approx 150 years old.

I want to brace these joices up with some 2x10 dimensional LVL beams running down the middle of the 16' span, and supported on the ends with solid piers.

How many 2x10 LVLs would I need to sandwich together to accomplish this?

Tis the season to rejoice!

 

[Zeke]

Tis the season to rejoice!

Or maybe he should re-joist.

 

[kert]

Or maybe he should re-joist.

Yeah that was kind of my point. Certain spelling errors make me cringe. Hate to be the word police though.

 

[rrangus]

If you are concerned about clearance, glue and nail/screw dimensional lumber to one or both sides of the joist after you level the floor. Also, always orientate the crown on the new lumber up.

 

[STINEY]

I get it.....I'm a grammer and spelling nut as well.

I honestly thought the plural of Joist was Joices, but after conferring with my dictionary I must yield the spelling bee to you fellows.

Thanks!


There is just too much stuff to move to scab a new joist to the old ones. Lots of plumbing, wiring, ductwork, and the wooden cross bracing that is supposed to make the floor less springy.

I actually have a 22' 4" steel I beam I thought I could use for this, but after sitting it on supports and standing in the middle, my 200# is enough to deflect it at least 1/2" - 3/4". I know deflection isn't failure for I-beams, but the point is to stiffen, so that is out.

I want serious overkill in a 8"-10" package that will fit on a 15" pier.

 

[Trey T]

Deflection is a comforting aspect and can be a failure mode in structural design.

Comforting aspect - live load causing springy floor
Failure aspect - dead load causing deflection. This deflection will cause creeping failure in wood. That's one bad thing about wood vs. steel, steel won't see the creeping failure like wood.

What are the live load moving across the floor daily? is it just human walking around?

 

[STINEY]

Yes, just normal dining room human traffic.

It is a pass-through room if you look at it as a traffic pattern, the rest of the house is accessible only from this room. So a lot of traffic, but only human/canine.