In a building more than 3 floors, is it better to use header design for top sills or just use(4) 2×4 stacked w/ concrete floors?
We have had some major settling in our builds where the framer and engineer have used (4) 2×4’s stack flat as there top sills between each floor of the building which is 6 stories tall on one side and 5 stories on the other, we have had more then 1 1/2 inches in settling in just 9 months and it is causing the plumbing tees to brake in the laundry rooms.
The floor in the apartments are gypcrete and the corridors are light weight concrete the studs are at 12 inch centers on the first 3 floor and the top 3 floors they increase to 16 inch centers. the plumbers are over sizing there hole by a half inch to allow for some movement. All the tees seem to be breaking at the top three floors.
I was thinking that the framer should have built headers on all the support walls to hold any increased weight. There would still be some settling but not as much since headers have more tensile strength the stack lumber. Oh yeh the walls do have doubled up 2×4’s in acordence with the engineering plan.
would this be an option ?
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Here's my advice: if you are building a 6-story wood-framed building, you need to take the advice of your structural engineer. If I were you, I wouldn't overrule my engineer based on advice you receive over the Internet -- even if it is advice you get for free on GBA.
If you and your framers have followed the advice of a structural engineer, and you still have the situation you describe, then you have a dispute with your engineer. If your engineer is honorable, negotiations with your engineer should result in a good solution.
i asked your location because BC is one of the only jurisdictions to allow six storey wood framed construction. While still quite new here, there are already well established details to deal with the anticipated shrinkage, including sliding couplings for all plumbing to prevent the problems you have had. While these buildings aren't easy to build, this sounds like a project where your consultants dropped the ball.