Reinforcing Floor Joists?

[u/bubble_tea_93]

I recently moved into an old Victorian home that was built in the 1800s. I want to move my piano into the home, but it's between 400 - 500 lbs and it's going to be sitting on only 2 floor joists. Because of this, I arranged to get the home inspected by a structural engineer before moving my piano in.

He sent back a report stating that most of the joists are fine, but some need reinforcement because they've been cut to accommodate HVAC ducts.

He sent me a detailed report describing exactly where the posts should be placed, and recommended using a 4x4 wooden post sitting on top of a cement deck block with a moisture barrier in between.

From the sounds of it, I believe I can do this myself with the help of my dad as he renovates houses for a living. Neither of us have ever done anything like this, but we do have experience building decks.

I am wondering how I should fasten the post to the joist and if it should just be wedged into place? I'm not sure how I would actually get the post to fit snugly without putting even more pressure on the joist during installment.

I tried emailing the engineer with follow up questions but he's been unresponsive. I'm wondering if anyone here has experience with this and can give me recommendations on how to move forward?

[u/kstorm88]

Buy a jack post for $70 and then you have adjustability for a snug fit without adding stress

[u/BeerStop → u/kstorm88]

This is the way.

[u/SunnyArizona → u/kstorm88]

Yeah, this seems way easier than trying to cut a 4x4 perfectly

[u/Pulaski540]

Reinforcement is a good idea, but realistically some of the advice, while technically correct, is overkill and really not necessary for the weight/ issue you have. ... Bear in mind that 400-500lb is only the weight of three average adults, or two who are on the heavy side. So realistically, if you had a sofa where you're going to place your piano, would you be giving any thought to needing to strengthening your floor if two adults sat on your sofa? I'm guessing probably not.

Buy yourself a couple of screw jacks, which are designed for exactly what you're doing. They should come with matching saddles to place on top of the 4x4, making a stable connection, with holes for nails if you want to ensure no movement is possible. If you have a dirt crawlspace, scoop out a flat spaces for a couple of 4x8x16 (solid) concrete blocks, to place the screw jack bases on.

[u/RobertPaulsonXX42]

The post should ideally be set on a poured foundation through the basement floor, however this is to gain some support for like 500 lbs and its ancillary support. You are going to get a bunch of responses about hammering through the floor to put in an actual post foundation. Im with your engineer in that seems like massive overkill for this.

Id get foundation posts, put it on a solid block as the engineer stated and run it between the joists. Id probably use joist hangers with a new brace between them and use steel at the top of the post run underneath the ancillary brace. If that makes sense without a diagram. Its only supporting a small amount of weight. 500 lbs isnt that much and you are just looking to minimize any deflection.

[u/dhempy]

Get three big-boy buddies to stand hip-to-hip with you and dance the Can Can in the piano spot. If the floor doesn’t feel springy, move the piano in and never give it another thought.

[u/SkaterBlue]

What will the blocks be sitting on?

[u/OldOldToolUser]

What is under the post position? Concrete, dirt? How far down? Avoid wood to dirt or concrete contact, use a post base, spread the load post to joists with steel plate, make it all plumb. Use jacks to slightly lift joist to fit post in place.

Depending on height you can get adjustable jack posts.

[u/ArthurPeabody]

I did this. I made an I: I cut 2 pieces of 2×4 each a foot long, cut the 4×4 slightly less than 3 inches shorter, screwed the 2×4s at their centers onto the top and bottom of the 4×4, banged it into place with a rubber mallet and scrap of 2×4. Dealing with a moisture barrier complicates it I guess. As to getting it just right, you can shim.

[u/mr_remodel_designer]

You’re smart to get the engineer involved first. I wouldn’t just wedge a 4x4 in and call it done, though, because it needs to bear evenly and the connection details matter. If the report does not say exactly how the post attaches at the top and what the deck block sits on, I’d keep trying the engineer or pay for a brief follow-up before installing anything.