Replacing/Sistering Floor Joists

[Anonymous]

Does anyone have a rough idea of what the current cost might be to replace or sister floor joists in a Capitol Hill rowhouse? Trying to get a rough sense of cost.

[Anonymous]

Hi,
Architect here. In most situations, sistering should be cleaper than replacing the joists. Again, LOTS of variables to consider, mainly the conditions of the masonry pockets (how the existing joists intersect the wall) and the conditions of the underfloor. Contact a GC and ask those questions... those two variables should drive the decision if sister or replacement.
I hope this helps!
ileana schinder
PS: feel free to reach out if it doesnt
[e-mail]

[Anonymous]

The existing joists are probably pocketed into the foundation walls. This means the sistered joists will have to be supported on both ends by supplemental beams and jacks. but it's really no big deal. The price is highly variable depending on the overall job. I would call 58 Foundations for both the best price and highest quality workmanship.

[Anonymous]

The actual work of inserting a new joist isn't that big a job. The question really is how much the house will have to be disassembled and then put back together again to get to where you can do it.

If the space on both sides of the joist is finished, one side will have to be removed and put back. If there are wires, pipes, ducts, etc., they may have to be moved out of the way as well.

It's really impossible to give a ballpark price without seeing. Every house is different.

[Anonymous]

Sistering can mean an entire joist span or just a section - which is your case?

I am doing this now as part of a renovation.

Cost of materials is $50/joist - wood, lag bolts, screws, nails, construction glue.

Labor is free (me)

Space is accessible but tight.

I would expect to pay 400/joist if I had to pay a contractor. More if it’s not easily accessible or requires additional support, say because it can’t rest on the rim of the exterior wall or the interior support beam.


Being in a row house and not knowing the dimensions or access points - can they get a single joist from the street to inside house work location without issue?

I have sistered entire joist and sections of joists that were rotten.