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I am doing some substantial refurbishment in my loft conversion, which basically involves moving a stud wall to make a bathroom smaller and a bedroom bigger.

I am in the process of lifting and replacing the floor (water-damaged chipboard). I have found that one of the joists underneath has a heck of a twist on one end.enter image description here

I wonder what to do about this: the joist hanger seems to be doing very little by way of support.

On the other hand, it seems like it always had a twist in it, given the rakish angle at which the joist hanger has been nailed in. I am not quite sure how long the loft conversion has been there (perhaps 2012, perhaps 2008).

Should I leave it, or should I attempt to straighten it (e.g. using X bracing); semi-orthogonally, should I replace that joist hanger so it actually does something?

Thanks.

Edit: I pulled a bit more plasterboard off, at Freeman's suggestion, to see how far the moisture had spread. Looks to me like it hasn't spread sideways at all - the timber is dry and unstained just ~20cm to the left.

enter image description here

Update: I've done one joist hanger, and corrected the twist, taking Tim's advice in his answer below. Woop woop! I'll do the other JH when I lift the floor over its joist.

enter image description here

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  • Both joist hangers shown need replacing. I would check to see if damage is just there or has gone further. The joist probably should have some bracing, but just to hold it in place, instead of trying to straighten. Main thing is to have it level with the tops of the the other joists so no dips in the floor.
    – crip659
    Jul 2, 2022 at 11:37
  • Those joists butt up to a steel I-beam. The hangars seem to be fairly heavily rusted, and the I-beam seems to have some light surface rust. Personally, I'd pull back more of the wall to give it a more thorough inspection. You say part of this was a bathroom, perhaps there was some flooding or just high humidity that wasn't vented that's causing this rusting. If any of those hangars fail, there will be nothing holding up this end of those joists - they are not nailed into the I-beam - there's not wood in there for them to be nailed to. Replace any hangar that looks sketchy.
    – FreeMan
    Jul 2, 2022 at 12:45
  • @FreeMan "You say part of this was a bathroom, perhaps there was some flooding" there was a stud wall running along the "double joist"; a shower tray was butted up to this wall; the walls were ply-lined under the tiles. The ply was basically rotten to a height of 6in above the floor.
    – Andy
    Jul 2, 2022 at 20:33
  • Yikes! I would definitely take more of the wall off to see what else was damaged! Moisture will travel horizontally just about as well as it will vertically.
    – FreeMan
    Jul 3, 2022 at 11:36
  • @FreeMan see new picture in edit. From my memory of the shower tray position, it looks like the leak was at the edge of the shower tray, but running back towards the corner (to the right)
    – Andy
    Jul 3, 2022 at 14:50

2 Answers 2

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In order that the ply sits level on the joists, they really need to be level themselves.To that end, the twisted joist will be better straigtened, to perpendicular.

Use bracing at bottom right and top left, to straighten the end, and re align the hanger. also use a couple of braces opposite those, again from adjacent joists.Although the right-hand joist has its own neighbour to push against. This may mean the joists next to those need bracing to their neighbours - which should have been done originally in some way.

When replacing the ply, screwing through to the errant joist would be better in the mddle of a board, rather that joining two boards actually on it.

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  • The bracing is called bridging . It should always be used , there may be some at another location on these joists but they could use more.
    – blacksmith37
    Jul 2, 2022 at 15:38
  • @Tim Can I just clarify what you mean: are you referring to herringbone bracing? I'm not sure what you mean by "at bottom right and top left". "Although the right-hand joist has its own neighbour to push against" Which is the RH joist? Do you mean the one immediately to the right of the twisted joist? That's actually not a full joist, it's a 2x4 nailed to the 2x7(?) immediately to the right of it.
    – Andy
    Jul 2, 2022 at 20:33
  • "at bottom right and top left" do you mean to put a brace going from the top left of the twisted beam to the top of the LH beam; and a brace going from the bottom right of the twisted beam to the bottom of the RH beam? Like this i.stack.imgur.com/3epvO.jpg
    – Andy
    Jul 2, 2022 at 21:07
  • Yes, both longer than they need be until the beam's straight again. Then put in proper struts perpendicular, or crossed, to beam, to hold everything straight. Obviously after taking out any nails, etc from the hanger first!
    – Tim
    Jul 3, 2022 at 16:08
  • @Tim how would you support the joist while the joist hanger is replaced? I don't really want to cut through the ceiling below to put in an acrow; could it be supported by putting a couple of lengths of, say, 2x6 or 2x8 at right angles, extending across several beams in either direction, and put joist hangers on those?
    – Andy
    Jul 4, 2022 at 9:29
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Came across this by accident (thanks Google). I don't know if you've had this professionally inspected but you really should. This is very dodgy construction and it's not really that surprising that it warped. You can't tie a joist to a steel beam like this and this is 100% not a LABC approved practice. Your fix is also not great. You need to put the noggins into the steel beam if you are going to use noggins but it looks like the joists are not long enough as they don't go into the beam. The noggins also get bolted to the beam which is really what ensures that the joists are held in place and will not warp. If you are going to use a hanger like it was done on your house, you can tie them to the packer, provided that it's correctly installed. The packer is the first board above the steel. You are looking at something like this https://www.youtube.com/watch?v=RtJVW1BimSw

You've attached a lot of weight to a few small 2x4 pieces above the packer. It's great that you nailed the crap out of it but all that's going to do is ensure that the pieces stay attached to the strapping rather than keep the structure together.

Also look at the wall, OSB offcuts are practically garbage and should not be used like this. OSB is an engineering material and it's usually used at lengths of 600mm or longer. So again, dodgy construction but if you want this fixed, best bet is hire a good builder and get ready for a major repair/rebuild.

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