Hello Folks!
In my daylight (walkout) basement there are two rooms on one side of the
house (opposite to the garage side) that I would like to combine into one
room. The combined room dimension would be 12’8″ by 26’10”. About 12′ from
the daylight wall is the load-bearing wall, which is framed with 2x6s
supporting above it 6 Boise-Cascade I-Joists on 24″ OC. The I-Joists
themselves are 1-3/4″ by 11-7/8″ running the entire length of the combined
rooms (yes, all 27 feet in length!).
I have spoken with BC, the lumberyard that supplied the original lumber on
my home (its a whopping 2 years old) and have been instructed to use 2 LVLs
on 1-3/4″ by 11-7/8″ for the width of the room (approximately 13’0″-13’6″),
nailed together to form a monolithic beam, and support accordingly. The
option of riding the compose LVL beam underneath the I-Joists or cutting
into them and using hangers is mine–according to both the lumberyard and
BC.
My concern at the moment is that the wall situation above this load-bearing
wall is almost non-existent. Essentially, the rooms in the basement (the
ones I’m trying to combine) mimic the formal living and dining rooms on the
first floor, which are separated by a couple of boxed column cold chases and
these columns are supporting some kind of beam (as the master bedroom with a
non-aligning wall exists on the second floor).
To install the LVLs into the I-Joist system I would be cutting into the
I-Joists and using hangers. This would essentially turn the 27′ long
I-Joists (six of them on 24″ OC) into unequal length I-Joists (approx. 12′
and 15′ lengths). The amount of section I would be removing from the
I-Joists would be twice 1-3/4″ thickness of the LVLs (total of 3.5″), which
is less than the width of the 2×6 wall I am removing. I do not think this,
in of itself, is a problem.
In order to actually get the LVLs lifted into place I’ll need to cut into a
top-plate on one of the walls that will terminate the LVL. I’d imagined that
supporting the beam could be done using 2x6s on either end, but how many
should I use? Since the LVLs will enter into the wall cavities of the two
walls it will intersect, I though I could minimally use three (3) 2x6s on
either end, but is this enough?
Now, you may be asking why I am going through this entire mess in the first
place as opposed to not riding the LVL beam underneath the joists. The
combined rooms will serve as a home theater and any second row of seating
will be on a platform riser of 12-14″ in height. This places one’s headroom
in dire position of any hanging beams that are below the joists.
This link shows a simple 2-D draft of the room’s layout. The option
equipment is not being formed (chose to do this elsewhere in the basement. I
could load some additional pics onto the same Yahoo Photo website if anyone
is interested. I would greatly appreciate and assistance in this activity. I
am a DIY, but have never attempt this sort of framing before.
Replies
kartman - If you can afford to do a home theatre, IMHO you can afford a few hours of on-site engineering from an architect or engineer. Depending on locale, you could need a licensed PE or architect to sign off anyway. Don't be penny-wise and pound-foolish in this case - it doesn't sound too difficult but some things shouldn't be done for free on the internet.
T. Jeffery Clarke
Jeff,
I wasn't trying to penny anything. Some people like to be personally involved and this encompasses DIY. As I stated, I have already spoken with a structural engineer at the lumberyard that supplies the BC engineered lumber for every home in the subdivision I'm in, which is only 25% developed, and he had complete architectural plans of my home (and everyone else's home in this development) on file for first hand knowledge of the structural condition/requirements, and stated his complete understanding of what I was seeking to do.
Additionally, I have spoken with an engineer of Boise-Cascade that not only made the I-Joists, but the LVLs they directed me to buy for this purpose. I do not think I have been skimping on the professional-side as I've spoken to two engineers intimately familiar with the products and my home. The architect for my home is an employee of the developer/builder, and it was the builder that agreed with the lumberyard's and BC's conclusion.
Its one thing to be told that 'this is what you'll need' for a beam and another thing for the practice of 'installing' said beams. Its was in the installation of these beams that I sought assistance. I've got a neighbor, but he is quite busy at the moment--but he is a licensed contractor. I may just need to wait him out as he offered to assist, but that could be several weeks to months.
Thank for replying, I do appreciate it!
If the developer and their architect are aware that both you and your neighbor are taking out this basement wall, maybe the cartoon lightbulb will click on above their heads and they'll see that it would be cheaper for them to build the remaining 75% of the houses the way people seem to want them in the first place.
-- J.S.
Well, of the 20 built homes and five under construction only 5 of them are using our floorplan and of them only my home and my neighbor's home has a basement. But, you are right. Then again, track builders are not buying what you and I want, but rather whatever they can get away with building for as little as possable keeping up with the current trends.
I would describe my response as 'frank' not rough. It's a good thing that you have the professional advice that you mentioned in your second post, because it is obvious to me that your project is not DIY work until after the framing is done. Being knowledgeable with respect to a system while a pro is building it is admirable - the design guides that BC and TJI put out are a good place to start (and BTW generally include trimmer requirements for standard loading conditions).
T. Jeffery Clarke
Quidvis Recte Factum Quamvis Humile Praeclarum
Edited 4/3/2002 2:16:25 PM ET by Jeff Clarke
Jeff, I did not mind your frankness at all. Growing up with 9 older siblings has taught me to see the information inside whatever tonal package it may be wrapped in. No problems here. I'll take what you had to offer like I'll take everything else--in stride. Cheers!
I don't think I'll be quite as rough on you as Jeff was, but he's partly right. What you're suggesting isn't easy, and has plenty of pitfalls. The number of studs you need at the end of the beam is the least of your worries. Other things like supporting the I-joists while they're being cut and the beam is installed can be difficult. One screw-up and you've got some serious problems.
Don't forget to talk to your local building inspector if you have one. Some of this stuff may be covered by your local codes, which we couldn't possibly know.
Boss Hog,
Temporary support walls on either side of the existing load-bearing wall are fabricated from 2x4 studding with double-top plating and single bottom plate using two diagonal cross members on either side for latteral rigidity. These are fixed to the floor using .22-charge-drive nails into the concrete floors and the top-plates of the temp walls are secured via 2x4s nailed into the joists' bottom style (spelling?) on either side of the temp wall (and running perpendicular to the joists).
Each of the two support walls are 3' and 4' away from the load-bearing wall and run the width of the room. I'm not sure if this is considered over/under kill but its in-place nonetheless. The temp walls themselves are using (plating mentioned above) 2x4s on 12" OC because the joists are running on 24" OC. I may insert blocker in-between the studs to assist the diagonal stiffeners.
I may use some 1x4 stock nailed into the styles of the joists near the existing load-bearing wall to keep the joists 'stiff' when cutting them, but I was going to leave that up to my neighbor (a licensed contractor) to decide. BTW, this neighbor had already pulled out this and two other load-bearing walls in his basement!
The local county building inspector is already aware of this project--as they are also out in my subdivision 2-3 times per week for homes under construction. This is considered small peanuts to them (but not to me). I wonder how long of a load-bearing wall needs to be messed with before they get excited.
I think three trimmers would be enough support inside the walls.
Dave
By hanging the joists expect a increased amount of deflection in your floor. You can try some solid blocking to take out some of it, but it is determined by depth to width ratio.
Danny, good idea! I could measure the distance between the webbing so adjoining I-Joists and chop wood for them. Then again, the intended 1x4 or 2x4 furring strips I plan on adding later in order to have a more plentiful screwing substrate for the drywall ceiling should assist in the inter-joist flexing that may occur.
I suppose I could attempt vertical stiffening by adding a third LVL. They are not that expensive (actually, $55!), so ...
Save your money, AS stated before it is the depth to width ratio that determines the deflection. If the joists were designed to sit on the girder then only increasing the depth of the joist will compensate. Blocking with pieces of the joist is the way to go, it gives lateral stability that you will not get with furring. I also recommend hat channel instead of furring unless you have a lot of time to shim your ceiling will probably look like the Atlantic Ocean. I am not trying to jump on the bandwagon, but the other replies had merit. It may be in your best interest to hire a qualified professional for the structural and install the wallboard yourself.
Edited 4/3/2002 2:49:16 PM ET by DANNYIF
Danny, by taking on the offer for free assistance of a licensed contractor that builds for a living and does side-work for the love of the job, it just happens to be that he is my neighbor. Coupling this position that I will have a professional being the complete build in the physical installation, we have both already consulted with the communities builder, their structural engineer, and engineers for the LVL's manufacturer and distributor.
Just because no money is exchanging hands does not mean I am not taking on qualified talent nor consulting with qualified individuals with intimate knowledge of both my home and the structural materials used to build it. The reason why I posted was because I was having a delay (free services come at a cost of paying services), and as my job places me in front of a PC 8 hours a day and that I have personal interest in front of the PC for another 2-3 hours per day, it was natural for my curiosity to post something.
But I would like to tank everyone for responding. Kudos!
Since you are now adding a point load to the slab you may need a footing to spread the load. Typicaly a bearing wall will have a thickened slab under it. This slab was not designed to take a column load. Where I live most column footings (as a min.)are 3' x 3' x 10" with #4 @ 12" both ways. The size will depend on your soil conditions. The lumber yard only cares about the lumber not what supports the lumber.
The points of the transfered load already have footings in place. Good catch, though.