Ask The Trades - Twisted Joist

BigClick

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Twisted Joist
Dec 6^th, 2009, 11:03am

Doing up my en-suite I have hit a major snag.
The room is about 2m square. The floor deck consists of a standard joist that runs along the outside wall, then a bigger joist (7x4) parralel to the other with a space just big enough to put the main waste. The rest of the joists are "hung" from the big one at right angles to form the majority of the en-suite floor.

The problem :-
After removing the boards from where I want the wet room former, the main joist (7x4) that the joist hangers are fixed to is twisted and so forms a a high ridge. This wasn’t a problem when it was a traditional shower tray, floor boards and carpet, but now it buggers up the level for the wet room tray.

I can’t see how I can work the joist to remove the effect of the twist without moving the joist hanger top portion out of the way as I do each section. I have thought about re-positioning the main shower area but it does mean less than ideal positions for the basin and radiator and I have no plans to move the toilet location because of how the main waste pipe is presented.

Any suggestions would be most welcome. Undecided

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big_all

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Re: Twisted Joist
Reply #1 - Dec 6^th, 2009, 12:54pm

pictures would be helpfull if possible

you dont say how much deveation you have
assuming your boarding with 12mm ply or simmilar structural
can you not solve it by a combination off methods such as

rebate in the hghest joist hangers
remove the high points on the beam

rebate out the back off the flooring up to a maximum 7mm

pack out between the ply and flooring to raise other areas

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« Last Edit: Dec 6^th, 2009, 1:03pm by big_all »

big all --------------- we are all still learning

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BigClick

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Re: Twisted Joist
Reply #2 - Dec 6^th, 2009, 3:09pm

big_all wrote on Dec 6^th, 2009, 12:54pm:

pictures would be helpfull if possible

Iwould upload a picture if I knew how to, is there a guide on here?

I could relief the plywood where the hangers are for the the area around the wet room former but I am unsure about how much modification I can do to former, having not even seen one yet.
If I lift the whole former then the resulting increase in overall level will mean a small step at the door threshold.

I wonder how falls were made before formers?

My Gallery has pictures of the scenario now

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« Last Edit: Dec 6^th, 2009, 6:23pm by BigClick »

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JerryD

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Re: Twisted Joist
Reply #3 - Dec 6^th, 2009, 10:04pm

Presumably, if the trimmer (the big 7x4) is bowing upwards (is this right?) then all the hangers will also be rising up to the top of the trimmer too. This means that all the joists are also running up to the top of this trimmer.

It's a lot of work to reduce the height of the timbers but it may be your only option. You'll have to 'peel' back the hangers from the trimmer and then plane everything flat again. Refit the hangers where you peeled them back and job's a goodun.

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CWatters Super Member Offline "Daddy fick it" says James Posts: 5150 Total Thanks: 58 For This Post: 0 Gender:	Re: Twisted Joist Reply #4 - Dec 7^th, 2009, 8:33am How to do photos.. http://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl?virboard=DiyB;num=1245961909
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BigClick

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Re: Twisted Joist
Reply #5 - Dec 7^th, 2009, 6:39pm

Quote:

Presumably, if the trimmer (the big 7x4) is bowing upwards (is this right?) then all the hangers will also be rising up to the top of the trimmer too. This means that all the joists are also running up to the top of this trimmer.

It's a lot of work to reduce the height of the timbers but it may be your only option. You'll have to 'peel' back the hangers from the trimmer and then plane everything flat again. Refit the hangers where you peeled them back and job's a goodun.

The joists are sitting nice and level in the hangers, its just the distortion on the trimmer, why is it called that? However I noticed a snag regarding the hangers, they were nailed on both sides of the big trimmer, presumably before the house was built up and I doubt I can pull the nails out let alone replace them on the channel side of the trimmer.

I have had a thought though, If I sit the wet room former tray on the joists before the trimmer I can lay marine ply with a gradient to the top of the former along the channel?

I would like to know if this is a workable alternative?

Thanks

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