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[Closed] Builders of singletrack. How to fit new joists on a extension.

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Any ideas?

1870 ish house with cheap 1920s kitchen and bathroom extension at the back.

Wanting to fit a new bathroom.

Our shower tray moves. A lot. I retiled a few years ago and the tray has pulled down and cracked the grout. I've now removed the floor boards and tray to find the joists are rotten around the shower area and one joist is nailed together in a crude manner with some random off cut of timer, the joists under have been wrapped in dpm by someone but they are completely shot.

I need to replace two joists and I can't "sister" them as the rot is where they meet the wall and 500 mm along into the room.

How do I set about removing the joists and inserting new ones. I'm confident in removing and supporting the floor etc whilst I do so, but I can't fathom how to insert the new joists when the room is 2500mm wide but the joist would obviously be wider to sit in the walls.....

Can't afford to pay someone as I'm on a tight budget and I'm fairly handy on the tools so I'm willing to try.

Ta.


 
Posted : 05/03/2019 2:56 pm
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Joist hangers bolted to the brickwork?


 
Posted : 05/03/2019 2:59 pm
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Depending on the walls you may be able to push the joist further into one hole, drop it down to horizontal then pull it back out and into the other wall. Easy if there is a cavity, harder if its single brick and plastered on the other side. You may need to enlarge the hole a little so it can go in at an angle. Another method is to fix a header to the wall perpendicular to the joists. Fix it well with chemical bolts then fit joist hangers to that and the new joist just drops straight down and into the hangers


 
Posted : 05/03/2019 3:03 pm
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Cut 1m out, enlarge hole width wise where joist is built into wall, this will allow you to get joist into wall and then on the angle to line up with existing. 1.5m of 150 steel plate predrilled on the zigzag either side, bolt through with coach bolts.


 
Posted : 05/03/2019 4:37 pm
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Thanks guys. Loads to think about. No simple way to bang a whole new joist in then. Walls are made of cheese which doesn't help! Should have bought a new build....


 
Posted : 05/03/2019 7:31 pm
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I've always found I have more depth to play with - so you can push back into hole and then slide out and they still sit on inner leaf of wall.

I would also consider bolting a wall plate against wall each side, using the existing joist holes for 'stub' of joist as well. Then joist hangers on the wall plate and joists across to fit.


 
Posted : 05/03/2019 7:43 pm
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I’ve always found I have more depth to play with – so you can push back into hole and then slide out

Dirty boy

But yeah joist parallel to wall and hang perpendicular joists to that


 
Posted : 05/03/2019 8:12 pm
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I forget what the actual amount of overlap of joist on masonry required by regs is but it is usually less than the brick plus air gap you to play with. Cut one end of joist at an angle insert other end as far as it will go and use angle to swing other end past wall.
Alternatively and often much easier, depending on what the exterior wall is, remove a couple of bricks and push all the way through from outside (assuming no neighbouring building is in the way)


 
Posted : 05/03/2019 8:26 pm
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I think the simplist solution would be to fit it on masonary joist hangers packed with slate to stop them moving


 
Posted : 05/03/2019 11:26 pm