Looks like I am going to use an LVL beam to take some bounce out of my floors instead of sistering the joists. With all the electric, HVAC and plumbing in the way, the sistering would be a pain in the a
.
To reduce the loss of head room due to the beam, I thought I read here in the Tavern that you could “let in ” the beam to the joists it is supporting.
My question is this – how deep can I let in a the beam to a 2×8 floor joist?
Replies
You can let it all the way in. Build a deadman wall on both sides of where the LVL will be. Carefully cut the joists out just wide enough to slip in the LVL. Install joist hangers on all the cut ends of the joists and woila! NOTE: I am not an engineer, though I did do 1 1/2 years of Mechanical Engineering in a previous life.
Let's not confuse the issue with facts!
Thanks, that's good news as I do not want to lose anymore headroom than I have to in this basement. I intend on consulting an engineer to spec the LVL beam size for me, but figured I would ask the carpenters around here about letting in the beam.
if the beam has to be any deeper than 7 1/2" you are going to lose head room.
The beam is likely going to be an 11+ inch LVL, based on my read of the LVL makers load tables. The final size will be up to an engineer of course. So I am going to lose head room, I'm just trying to minimize it by letting in the beam.
If your joists are old rough sawn 2x8s, you can order hangers for full 2" material. I've ordered them through a local lumber yard, from Simpson.
Bowz
I'm glad you mentioned that since the thought had not crossed my mind.
pino......I may be splitting hairs here....or it could possibly be a regional term.
Around here anyway, what you are attempting to do is "up-set" a girder. That is, setting it up into the framing.
When I hear "let in", I think of balloon framed walls, where the rim joists for the floor framing is "let into" the studs. (Studs are notched the thickness and height of floor joists to allow them to sit flush with stud faces.)
Anywho....the advice you`ve received thus far appears on point. Kudos to you for consulting an engineer.
ATTENTION FELLOW BREAKTIME MEMBERS:
If you`d like to discuss topics other than home building, come on down to the Woodshed Tavern. Great bunch of guys and gals letting off a little steam about everything and anything. Its not a special club, but.....as of Monday, March 14, the Tavern folder will go behind an access wall. Only those who request access to this folder by contacting [email protected] will be able to view and participate in discussions there.
Well Jay, you know I am no pro, just an over achieving HO (or is it over reaching?). It is likely that I used the wrong terminology, so I do appreciate the correction.This little project is turning into a real pain in the a##. I tossed aside the idea of sistering up the joists because removal of the electrical, plumbing and HVAC was too involved.Now I'm thinking of just adding in a beam near the joist's mid-span, but at 22' an LVL beam would have to be 20" deep to minimize deflection at the estimated loads I came up with. I want to minimize loss of head room and don't want a mid-span support for the beam, so now I am going to look into a steel I-beam.I'm trying to get my ducks in a row before going to the engineer.
Edited 5/31/2005 2:27 pm ET by pino
I would try to avoid the steel. I always find steel a hassle to work with, and the price of steel is pretty high. Sometimes steel is necessary, but I'm sure there is a properly sized glue lam you can use. You get a glue lam that is 7" in width and your depth wont have to be anything crazy. But of course.... as long as it is engineered.
By all means, I would like to avoid using steel.Problem is, with a LVL I was told that given the span (22') simply increasing the width of the beam has negligible effect of deflection. Thus, I am looking at an 18" deep beam which eats up a lot of head room. My hope is that a steel beam would allow that depth to drop considerably, but I'm guessing that the increased weight of the steel might be self defeating when it comes to deflection.Jay's idea of adding a steel plate in between two LVLs to stiffen things up sounds plausible. Guess it is time to go find an engineer to check my load calculations and make a recommendation.
Perhaps a steel flitch plate (As opposed to a steel "I" beam) sandwiched between the LVLs will take care of the deflection.
I`m not an engineer, but I do play one on the jobsite. ; )
ATTENTION FELLOW BREAKTIME MEMBERS:<!----><!---->
If you`d like to discuss topics other than home building, come on down to the Woodshed Tavern. Great bunch of guys and gals letting off a little steam about everything and anything. Its not a special club, but.....as of Monday, March 14, the Tavern folder will go behind an access wall. Only those who request access to this folder by contacting [email protected] will be able to view and participate in discussions there.
after it's sized ...
get the final weight.
Bet U can rent a hand crank Genie lift to help get her up there.
set the forks "low" .... and lift up to saw horse height.
set the horses under it.
then set the beam on the horses .... move the lift back ..
and turn the forks over ....
now ... U can lift it flush to the ceiling ... or less than flush as yours sounds like it'll be.
3 people makes for a good crew size .... cost a bit more ...
but no one actually breaks a sweat ... or pulls any important muscles.
Nice part is the lift will hold it up there as U move in the supports .... do last minute "fine" adjustments ... drink a beer ... etc.
Jeff
Buck Construction
Artistry In Carpentry
Pittsburgh Pa
Thanks for the advice. I'm sure that beam is going to weigh in heavy, be it LVL or steel. Good thing I've got some neighbors that owe me.
Try solid blocking at 1/3 and 2/3rd points, then nailing a metal strap under them, ie at rightangles to the joist spans. Canadian building codes indicate a significant reduction in bounce that way.
cheers
I've got true 2 x 8s spanning 17'-6". While blocking and strapping no doubt reduce bounce, at that span I have been advised that such a solution will not adequately reduce deflection. If I remember correctly, my 2 x 8s should not span more than 12'.We had thought about sistering up the joists then adding in the blocking and strapping as you suggested, but with electrical, plumbing and HVAC in the way the beam idea is now more appealing.
Pino,
If you are really familiar with the way a house works, you could go to betterheader.com and use their span tables. They have tables for center girders in lvl, flitch plate, and steel beams. I used them for specing a couple of beams and came up the same as the engineer we use for stuff like this.
Either you could look it up, or you could pay an engineer to do the same, long as you know how to read a table, and there arent any other loads (roof, etc) that bear on the floor that the table wouldnt know about.
Thanks, I'll look into it. Ultimately I am going to consult an engineer, but I want first to inform myself as to the various options available to solving our problem.
Always the best course of action.