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A. Spruce
2x4 engineered floor trusses
Bkhackworth wrote:

I'm going to try and include some pictures.

You'll need to use a photo host site, then link the images here.

As for your issue, the pics will help us understand what you're describing. I would think that you could easily enough jack up and sister the engineered joists with dimensional lumber. Assuming that this is a crawl space, you can also add a pier under the point of load, or a series of piers.

Re: 2x4 engineered floor trusses
Bkhackworth wrote:

Picture link added to original post

Well, now your original post is missing...try again.

Re: 2x4 engineered floor trusses

This site will not allow me to approve posts that were edited to add pictures, so here is the original with the photo link.

Bkhackworth wrote:

My wife and I purchased a home that was built in the early eighties and has engineer 2x4 truss floor joist 24 on center. In the kitchen the floor has sunk about an inch where the refrigerator sits. We did some checking and located the issue. The builder placed a load bearing wall 11 inches off of the location where the two joists (one 14' the other 12' long) joint together and the proper location for a load bearing wall. I've called in one contractor who has queried and engineer that immediately said the joists have to replaced (with out looking at them). My question is, is there a way to streghten the floor trusses with out removing them while restoring some of the elevation lost (1/2in maybe). The trusses have keep the existing dimensions on 12" toward the exterior walls but in some cases have compressed to 11" where the wall was placed incorrectly. I'm going to try and include some pictures.

Picture link


Re: 2x4 engineered floor trusses

That's a tough problem. While an easy answer is to replace the trusses, it's not very practical.
Does the main problem seem to be the bottom chord at the bearing point seem to bowing allowing the whole truss to sink a little? Does the connection between the trusses where the bearing should be appear to stable?
It seems to me that if the floor could be jacked up additional reinforcement such as steel angles bolted to the bottom chords to prevent crushing/bowing at the bearing.
Maybe some struts could be attached to direct loads back to the bearing wall. Could be wood or steel.
Some solid blocking or plywood gusset type plates on the outside of the trusses might go a long way.
Another solution might be to stabilize the what you have, then pour a lightweight topping on the floor to level it.
Your measurements don't all seem to add up. Ther could be other problems.

Re: 2x4 engineered floor trusses

The best approach would be to install a beam under the unsupported wall, adding squash blocks on both sides of every truss to transfer the load, then to raise the beam to it's proper location and permanently support it there. The squash blocks and their beam dis-involve the truss in supporting the wall. Do not try to raise these kind of trusses by lifting them directly; that can damage them. Have nothing heavy on the floor while lifting (like appliances). Once the lift is complete, check for sag mid-span and truss condition overall. If anything is not acceptable you'll need to either sister dimensional joists in or if the span and situation allows, create a a diaphragm structure by adding 3/4" plywood to both sides of the truss, glued and fastened by nails 6" apart, as each is lifted individually using a beam underneath to spread the lifting load across at least 1/3 of the spanned area.

These are the general procedures for this process. Trusses are supposed to be engineered to each job and given correct support as directed by the truss engineer. To be code-compliant you'll need a truss engineer to design the span repair, or any added joists will have to be adequate for the entire load all by themselves and act independently of the trusses

Were this my job I'd begin by going to the building code inspection office and inspecting the blueprints they should have on file for the house. I'd see if the walls and supports were all done according to that design. On the drawings should be the name of the truss supplier and their job number, and perhaps the truss engineer's stamp. Then I'd contact them to get advice for the repairs. If the house was built exactly as drawn then the truss engineer screwed up and can be sued for the faulty design and repair costs. They will know that and will likely bend over backwards to help you out rather than risking having their engineer's license revoked. If the builder screwed up they are the best people to design the repair for you as it's their product. There would be a cost for that, but you end up positively code-compliant which may be important when the house is sold next time. There may be some accessible liability from the builder if they did not follow the drawings but this far along I doubt they can be held liable. A local lawyer can answer that for you.

Trusses when done correctly can be OK, even allowing for spans which would be extremely costly to do otherwise, but as an engineered component they do not allow for any variance from plans nor may they be altered in any way or have a different load applied to them than they were designed for. They have no design flexibility or adaptability to future changes. Anything you do with them requires an engineer's involvement and cost, and many things possible with dimensional lumber construction is impossible to do with existing trusses. Just another reason I like old houses bettercthan new ones.


Re: 2x4 engineered floor trusses

Any truss needs to bear on a panel point designed for that. These obviously don't. Someone screwed the pooch on this one. Good luck finding anyone from the early eighties to take any responsibility. Not sure I'd go to the building department for anything. I believe a good contractor could figure out a solution. An engineer too if you paid him to look at it and design a solution.

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