I recently purchased a fixer upper built in the 1930s in MA. The basement ceiling had lathe and plaster I removed so I can shove some insulation in. The removal has revealed a few joists in bad shape, and that they are notched. Apart from the three concerning joists, all the other ones are in pristine condition and all the bridges are intact.

The three joists are each concerning in different ways.

Joist #1 has been bored perpendicularly to fit a toilet (that I've removed). There's abviously some water staining there as well which will no longer be an issue. I think what I need here is to sister the joist locally:

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joist #2 has a hairline split all the way through, but only on one side. The end of it is attached to a beam in a really funny way. I'm on the fence on whether this needs sistering or not, thoughts?:

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Finally, joist #3, the one I'm most concerned about is cracked in two spots. One of the spots is cracked where there's a big knot. I'm pretty sure it shouldn't have been used in the first place because of the size of the knot. I think I need a pro to come and sister it the entire length:

the first crack where the knot is: enter image description here enter image description here

The second crack further down: enter image description here

So my question is, what kind of professional should I look to hire -- I know I need a carpenter, but do I need a structural engineer to come and look at it, or should I look for a carpenter that specializes in framing, or is this rather run-of-the-mill and any experienced carpenter will be able to do the job well?

Thanks! -Matt

  • Do you have any issues with the floor above? That answer is your answer.
    – DMoore
    Apr 30, 2021 at 16:55

2 Answers 2


I would get a General contractor, if you can’t drive a couple of nails or screws.

As far as urgent , probably not at all urgent.

I would want some joists hangers on the ones hanging down and only toe nailed.

the long horizontal split no worries there if you want sister if not every house has those.

The last one with the knot and split maybe sister but it probably has been like this for decades.

Do you need someone else to do the work NO.

Every old home I have worked on has very similar things that because of the quality of the wood is not a problem.

Horizontal splits I don’t even think about if the split runs at an angle in the center of a joist sure sister it. A simple car Jack to put a bit of upwards pressure then nail or screw the sistered board to the split one, if you can extend the new board ~3’ past the break out point. Don’t push up too hard or you can create other problems.

These are easy repairs and based on taking down the old plaster you probably have the skills necessary to reenforce your areas of concern.


A structural engineer will tell you what size joist is required if there were structural changes to the building, or sign off on tolerable damages for insurance etc... This is likely not what you need.

A carpenter will know how to fix it without input from an engineer. The carpenter can get a good picture at a visit, advise you on the minimal work required (if any), and point out other things that could be fixed since you have the ceiling open. You can also pay for the advice and then do the work yourself.

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