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I am getting ready to install a new bathtub and shower.

After ripping everything out I noticed all the studs behind the original bathtub wall have cuts. See photo.

If anyone can explain why the studs are pieced together this way I would appreciate it very much.

[image of studs connected together with a zig-zag joint1

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Those are called "finger jointed studs". These joints are weaker than regular 2x4 or 2x6. I do a lot of woodworking and when gluing boards together (for like a table top) the glue joints are actually stronger than the wood itself. But for some reason, that's not the case with finger jointed studs, they are just much weaker than the intact 2x. That and the alignment issue between the pieces make this product junk if you ask me.

The contractor that built my house started using them for interior walls. Some of the joints were off by as much as 1/4", which would have made sheetrocking much more difficult. My plumber said he hates them because unless you brace the stud when drilling, they'll break at the joint. To demonstrate, he got a short length (about 4') with a joint in it, elevated one end on a 2x and then proceeded to kick down on it. It broke right at the joint.

After a few interior walls were built with that crap, I inspected and found many cases where the joint wasn't at all even. I told the contractor to tear those walls and not use that crap anymore. He didn't like me for it, but later, when he used them on a project for himself, he admitted they were crap.

To answer, since they are already in place I wouldn't worry about it. The vertical load capacity isn't affected, esp. not an issue in a non-load bearing wall.

Sorry for going off like this, but finger jointed studs are just not a good product.

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  • 5
    I've not seen these issues before. It's possible that you are commenting about the quality of the manufacture, not the product. And then the answer is to not buy cheap finger jointed wood. It's no different than regular wood, the less $ the more issues...
    – Ack
    Nov 15 '20 at 17:43
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    Is Steve Wellens the author of a deleted answer? Or some other pundit? In either case, we're missing context here, including what we're comparing ("cheaper and weaker") it against (some other joint, I presume?). Can you rephrase those first few sentences so that this answer is self-contained? Nov 16 '20 at 11:19
  • 1
    I sympathise with your feeling on this, but it sounds like you're in a country that lacks minimum standards for building materials, vis some of the other users. In New Zealand we have codehub.building.govt.nz/home/resources/14911996asnzs and codehub.building.govt.nz/home/resources/8008int2014-asnzs which is "a specification for finger-jointed structural timber viewed as substitute for solid timber" and describes minimum values for everything you might measure. This is a different level to the local sawmill's offcuts pile and some wood glue that sellers peddle.
    – Criggie
    Nov 16 '20 at 11:31
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    @FreeMan there is a world of difference between a laminated beam (lots of glue area between the pieces, unbroken pieces next to the joints) and a single stud (barely enough glue area to hold the two pieces together until installed). To get something mechanically similar here, you'd have to glue a short length of wood on both sides of the stud joint.
    – Olivier
    Nov 16 '20 at 15:19
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    Notes that this is why "opinion" based questions are Off-Topic here. An "opinion" based answer has generated a fair bit of controversy... :)
    – FreeMan
    Nov 16 '20 at 16:07
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That is a join between two bits of timber.

The ends are machine cut and glued.

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    Done at a factory to make full use of shorter bits of wood. Just as strong and straighter than one long bit of wood. Nov 15 '20 at 15:49
  • Thank you both for the explanation. I don’t think I’ve ever seen these sold at a Home Depot or other big box store but then again I may just have never noticed them before.
    – homegrown
    Nov 15 '20 at 16:19
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    They are becoming more common. The reason is scarcity of wood / less waste (more 'green'). These studs are in affect made from scraps or taking the quality pieces off of a solid wood stud that has bad unusable sections.
    – Ack
    Nov 15 '20 at 19:20
  • I see those types of joints a lot in trim wood, but never in a 2x4 wall stud.
    – SteveSh
    Nov 16 '20 at 19:07
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As others have said, this is "finger jointed" lumber. The quality of such lumber varies from quite good to kind of piddlin' poor. The purpose of the joints is to allow knots and other bad spots in the lumber to be cut out, producing a piece that is straighter and easier to work with than it would otherwise be (and of course allowing longer pieces to be produced from a given tree).

The care taken in cutting the joints plus the amount and quality of the glue used determines how straight and strong the joints will be, though the quality of the original lumber is also a factor.

And note that similar joints are commonly seen in wood trim, particularly in exterior trim. In exterior trim eliminating knots and splits is especially important, so the use of the technique definitely improves overall quality without running costs sky-high.

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    I have to disagree. the softwoods (hem-fir, etc.) used can have substantially different movement during drying. If the manufacturer re-milled them after drying it would be better, but still not good. This is just a way to stick together leftovers and try to market an inferior product. They are garbage. I don't usually get this emphatic here as I totally respect others comments, usually they have a lot more experience than me. But having personal experience with finger jointed studs, I'm going out of my own bounds and calling them out as unmitigated crap.. Nov 16 '20 at 8:04

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