Found a new-construction home I want to purchase, but I have serious concerns about the roof trusses and ceiling joists. The house is completed on exterior (bricked, windows, and roof completed) but interior is unfinished. Studded walls show floor plan laid out, but no drywall, no electrical/plumbing/insulation/cabinetry/fixtures, etc. House completely unfinished on interior other than studded walls throughout and sub-floor. Center of home is one very large, open space for main living space- living/kitchen/dining, and measures 33.5'x 20'.

My biggest concern is this: The ceiling joists(which are part of the roof trusses) run the direction of the 33.5 feet in the room, and are only made of 2"x4"s (seems way too small to me), which are connected by metal brackets which connect the 2x4's end-to-end, and there is obvious sagging in places along these runs of 2x4's. Obviously, once you hang drywall to make your ceiling, you would have even more sagging! There are no cross beams to add support anywhere in the 33.5'x 20' room. The roof trusses are made of 2x4's also, and all of this is spaced on 24 inch centers.

Someone has made chalk lines along the worst sagging areas, and the chalk line is over one third up the board in places, so cutting them to even them out would weaken the structure I would think (someone told me you could do that!)

I'm just trying to decide if I should run for the hills, or is this not a deal breaker? Absolutely everything else about this house and property is perfect, as we've been looking for well over a year now! Any information from those who're knowledgeable about roof trusses and ceiling joists in new-construction would be very much appreciated!

  • Forgot to mention that when standing in front yard looking at roof (not the peak line of roof) you can see a few spots of very subtle dips! – Garry May 15 '17 at 8:18
  • What is the pitch of the roof? Our truss roof is a low slope 3 in 12 pitch roof (straight gable oriented front to rear) and we had a roof leak at a dip in the decking (not in the trusses) near the ridge line. The decking separated at a butt and that small change in angle allowed water to get under the shingles. I forced it up inside the attic and put in 2x4 blocking and the leak stopped without my having to do anything to the shingles. – Jim Stewart May 15 '17 at 11:36
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    There's something odd about your description. For one thing, 2x4 bottom chords are perfectly acceptable. In an engineered truss, they tend to span no more than about 6 feet, and they're supported by the webbed structure above. How long are the spans in your case? Then, the sagging you describe doesn't sound like sagging. It sounds like warpage. Unladen ceiling joists in an engineered truss should never sag visibly. Please edit your post to describe the spans of the joist segments (between gussets), and add clear photos if at all possible. – isherwood May 15 '17 at 14:03
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    As the question stands I'm voting to close as opinion-based. Garry, if you'd like to add detail and photos and ask something more specific, please do. We're not a discussion forum, and this is a question of risk tolerance the way it's written, which is off-topic. – isherwood May 15 '17 at 14:07
  • Would guess pitch to be around 10:12, with straight gable oriented side-to-side. Maybe it is warped. I understand 2x4 bottom chords are perfectly acceptable, as is on 24" centers, but my concern is whether they are acceptable for an open space of 33.5'x 20', with no other supports in place? That seems like lots of weight being added once drywall,ceiling fans & light fixtures installed, with no other support for such an expanse of space? Spoke to the builder this morning, he said "the truss company is working on it & supposed to be at the house this week to fix it". Did not take pictures. – Garry May 15 '17 at 14:48

There is probably a very good reason why this house is sitting there in this unfinished state and up for sale. You should definitely do a detailed investigation of the history surrounding the design, permitting and construction of this house. You may very well find information that would help you understand just what you are getting into should you stay on the path of purchasing this unfinished shell.

The issue that you describe is a very big problem and could very well require removing the roof and replacing the trusses with properly designed assemblies on proper spacing. What may look like a very good deal could end up costing you way more in the long run to get the problems corrected and to pass inspections.


Our neighborhood of ~250 tract houses (built 1969-70) has roof trusses of 2x4s on 24" centers. Our house has double Fink trusses about 40' long with a 3 in 12 pitch of the roof, except for the front living/dining room which is a vaulted ceiling supported by 2x12s on 24" centers. The trusses seem to be fine. Our ridge line does not droop in the middle. The roof decking is ca 3/8" plywood and is like a trampoline. There are no blocks between the trusses and the spacing varies. Over our 39 years here I have put blocking in a few places when the roof decking failed at joints stiffened only with aluminum H-clips.

I think you would have to get a truss engineer's report on the status of the sagging bottom cord of the trusses. What about the top cords?

Double fink truss

Double Fink Truss

  • I believe the truss system you have pictured here is the same as in this house. Not sure about the top chords. I think they looked ok. The subtle dips you can see on the exterior roof appear to be between the truss supports, and between the two dormer windows. Spoke to the builder this morning and he said "the truss company is working on it, and supposed to be at the house this week to fix it". We will have a qualified third party to thoroughly inspect the house prior to us making an offer! – Garry May 15 '17 at 14:33
  • What is the pitch of the roof 3-in-12, 4-in-12, 5-in-12 . . .? – Jim Stewart May 16 '17 at 10:54

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