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An error while constructing new triple 2x10 beam

10K views 12 replies 6 participants last post by  WillK 
#1 ·
The picture below won't show the error, but it shows what I'm doing so I'll start out by explaining what I'm doing:

So my house doesn't have a foundation, and we're going to get to that eventually, but in the mean time I'm adding posts and beams underneath supported by spread footings. I'm working from plans drawn up by a structural engineer. Once the new posts and beams are constructed, I will begin setting the house on the beams, taking weight off the cement blocks holding the house up, and replacing floor joists.

The as-built construction is that the house is 22' wide, the floor joists butt against eachother in the middle, the floor joists are 2x6 and the beam in the middle is triple 2x6. The beam has joints that are unsupported, many floor joists have been sistered 1 to 3 times, the floor varies by up to 3".

So my construction process has been to dig footings, get them inspected, pour concrete and set brackets, allow the concrete to set up at least a week before I even attach posts (in the case of the posts for this particular beam, they sat unloaded for 6 months). I have installed the posts with the tops level and flat and the post set vertical by level in both directions.

To construct the beam, I'm starting from the front. (The front room actually is specified as only needing double 2x10, so one of the 3 lengths terminates at the last post before the front room) So I lay a board on top of the posts, apply glue, set the next board on, apply glue, then I flip the assembly upright so I can nail it with my framing nail gun.

Here's where I made an error: After I flipped the assembly up, the center board visible in the foreground was pushed up at the end by heating ducts and I didn't realize it until after I drove my first nail. The nails shoot in such that the heads are below flush, and even if I could pull it out it would be hard to move because of the glue.

Can I correct this by cutting off the excess on the top with a sawzall after the assembly is complete and shimming underneath at the posts? Or will I need to start over to make it right?
 

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#7 ·
In this particular case, I'm already deviating from the approved plans by exceeding them. The original plans call for triple 2x10 beams at each perimeter wall and utilizing the original triple 2x6 beam at the center and the original 2x6 joists. I'm replacing the single beam of triple 2x6 with two triple 2x10 beams and upsizing josits to 2x8, and because I'm going from 3 beams as originally specified to 4 beams I'm cutting my joist span to 2/3 the original span.

Beyond that obstacles have also forced me to reduce the span between posts for this beam and increase the number of footers from 6 to 8... So assuming the approved plans are a minimum, I'm comfortable as a non-licensed engineer that I've added for more design margin than would be lost by this deviation.

I'm just anticipating his response, I know I should talk to him, but it'll probably be a verbal okay over the phone anyway.
 
#2 ·
Whether it is "right" or not that is exactly what I would do, lol.

There are circumstances where that is what you HAVE to do. I just opened up a large section of load-bearing wall in my slopey 1925 house and supported the opening with three 2x16x16 LVLs sistered together. Problem was, with the house sagging a bit in the middle, the joists in the center of the house were close to 2" lower than those near the sides. I had no choice but to level the LVL assembly to the lowest joist and then shim up the rest as trying to level the joists would have opened a hornets' nest of other problems.

I would not use a sawzall though, I would lay that thing flat and run a circular saw down it. Doing it with a sawzall will give you an uneven cut to say the least.
 
#3 ·
What do you mean."pushed up at the ends by the heating duct"?
Too much space between the beam and the support?
Not enough clearance?
Duct in the way?
Not following the issue.
 
#6 ·
Okay I can explain a little further what I'm doing.

I have 2 footers in this line which I poured 6 months ago, those two are cured and have posts installed. I am beginning the construction of the beam with those two posts as support. I will use the beam to align the post brackets so they are centered under the beam.

The center board is misaligned. I had everything straight when I created the sandwich of 3 boards glued together with the boards laying on their side on top of the 2 posts. In order to get enough clearance for my nail gun, I had to rotate the glued and clamped beam into place.

The duct is in the way. This resulted in the 1 board being pushed above where it should be in order to be level. When the new joists are installed, they would bear on the 1 board instead of all 3. On the bottom, 2 boards will bear on the post instead of 3.

My choice of sawzall was one out of practicality because I felt it would be the easiest to maneuver within the space available, that a circular saw might hit the joists, but if it clears the circular saw would be the logical choice. Actually I think it would be ideal for creating a wedge that I could use to shim the gap on the bottom since it will very closely match the gap.

I had not considered turning it on its side. In its current state the beam is a total of 49 linear feat of 2x10 lumber and I can barely flip it up. By the time I add the boards I'll need to make the cut, I'll have a beam built from 91 linear feet of 2x10 and I'm working by myself. I don't think I could handle that much weight while crouched in a 30" deep crawlspace.
 
#5 ·
If I understand this correctly; the center 2 X 10 of the girder is a bit higher than the 2 X 10s to each side of it so that when the girder is supporting the floor joists the joists are in contact only with the center 2 X 10. If that is the issue then it would seem that you could knock down the center 2 X 10 at each bearing point, e.g. every 16", with whatever you can work with in the crawlspace, circular saw, hammer and chiesel or a sawzall (as Ironlight pointed out it can be tough with a sawzall, but if you are only cutting a bit off the top (3/16"?) of the 2 X 10 for 2" for the joist to bear you could likely do that, I don't see you cutting down the length with a sawzall and getting a decent cut). good luck with the project.
 
#8 ·
I am totally confused but just want to say one thing you reference the ductwork.
When rebuilding the main beams for a house the last thing I would be worried about is the ductwork which can be moved, cut, reran, resized, whatever. Don't even worry about it focus on the main support.
 
#11 ·
I am totally confused but just want to say one thing you reference the ductwork.
When rebuilding the main beams for a house the last thing I would be worried about is the ductwork which can be moved, cut, reran, resized, whatever. Don't even worry about it focus on the main support.
I agree, and I just want to point out that isn't a concern. The only way the ductwork comes into the story is that I have a rigid duct pipe that I thought was low enough for the beam to clear, but it wasn't and the one board was able to slide since the glue hadn't set.

Way further down the road, all of this ductwork is going to be replaced. The furnace is currently in the crawlspace and has no central airconditioning. I'll eventually get a new furnace with central air, and it will be installed under a new staircase which will be in a different location than the present staircase. With this I will have new ductwork and the old hodgepodge of rigid and flexible ductwork will be discarded.

I'm attaching another photo showing the duct work which interfered with the beam. Both photos were taken from the same point by sticking a camera down the same crawl space access hatch. The first photo is looking towards the front of the house, the photo attached here is looking towards the rear of the house.

I am considering replacing all the ductwork with flexible insulated heater ducting anyway, just to get a good clean heated air delivery system that eliminates the dust, clears up any interferences, I'd get it hung from the joists and/or beams to eliminate some kinks and holes that the system has.
 

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#9 ·
It appears you have effectively redesigned the entire project, and are using substantially larger lumber than specified. No problem there, only cost.

I think I understand what you are saying, maybe. I believe you are saying that the center member of the triple beam is higher than the outside members, due to some sort of construction problem. It is OK to have one member higher than the others, this has no effect on the strength or stiffness of the beam, it only affects direct compression and vertical shear, which almost never controls in residential construction (ask your engineer to confirm). The issue is whether the top beam is level, which it clearly needs to be unless you want a sloped floor. If you can install the triple beam so the top is level, it doesn't much matter if the bottom of the beam is out of level. If it is impossible to get the top level, well then you have to cut the protruding beam down to make it level, which may require you to cut it down so it is flush with the other two members. This can be done with a sawzall, or with a hand plane for that matter, so long as there are no nails to go through, in which case a belt sander might be the implement of choice.
 
#13 ·
It appears you have effectively redesigned the entire project, and are using substantially larger lumber than specified. No problem there, only cost.

I think I understand what you are saying, maybe. I believe you are saying that the center member of the triple beam is higher than the outside members, due to some sort of construction problem. It is OK to have one member higher than the others, this has no effect on the strength or stiffness of the beam, it only affects direct compression and vertical shear, which almost never controls in residential construction (ask your engineer to confirm). The issue is whether the top beam is level, which it clearly needs to be unless you want a sloped floor. If you can install the triple beam so the top is level, it doesn't much matter if the bottom of the beam is out of level. If it is impossible to get the top level, well then you have to cut the protruding beam down to make it level, which may require you to cut it down so it is flush with the other two members. This can be done with a sawzall, or with a hand plane for that matter, so long as there are no nails to go through, in which case a belt sander might be the implement of choice.
It sounds like you're understanding, yes the center board will end up higher than the rest of the beam, so when I get to the point of installing joists to the beam I'll notch it at those points.
 
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