Renewing a joist in an awkward place

[Anonymous]

I need to renew a joist which runs under the wooden structure which houses the stairs. There is limited access on both sides of this stairwell, and the only way to renew, with one uncut length of joist, would appear to be to take apart the stairwell, which I really want to avoid.

This joist only supports a floor, as the walls are 2ft thick and support themselves. Does anyone know of a "bolt together"- type joist product, which could be manoeuvred into the available space. Or any other ideas. Thanks for your help.

Ross

 

[Anonymous]

Is it possible for you to bolt a strengthening member on to the side of the existing joist? The possible success of this rather depends on how badly the original has failed, and whether its ends are still soundly housed in the supporting walls.

 

[Anonymous]

David

Thanks for the reply. The joist is rotted and so need st be replaced completely.

Ross

 

[Anonymous]

OK. This is difficult to explain verbally, but having re-read your post, I'm assuming that you can lift floorboards on each side of the staircase, and can therefore gain access to the point at each end of the rotted joist where it houses into the walls.
If this is correct, here's a suggestion.
Lift floorboards to gain as much access as you can on each side of the staircase. Cut the rotted joist into as many manageable pieces as you can and remove it. Hopefully you'll be able to reach in under the centre section with your crowbar to prise the inaccessible bits off the floorboards.
Using timber of the same section as the original (make sure it's pressure treated or at least soaked in wood preservative), cut three pieces - one for each end to house into the wall sockets, and one to span the centre. The centre section should overlap the two end pieces by as much as possible, enabling you to pass two or more bolts through each overlap. The further apart you can get these bolts the better.
Obviously the practicability of this idea will depend on whether you can lift enough boards on each side of the stairs to feed in the long centre section.
One further thought: If the old joist supported any floorboard joins, then the fact that the centre part of the new assembly will be offset from the position of the old might leave these joins unsupported. In this case you'll have to plant additional pieces on the side of the new joist underneath the board joins.
I hope that all makes some kind of sense. If it's gobbledegook, let me know and I'll try to post a rough drawing.

 

[Anonymous]

I would do something similar to David's suggestion, but make the two sections inserted into the wall meet in the middle at a 45 degree angle (if you see what I mean) as well as bolting the bridging piece to them - this would provide more secure support.

An alternative (depending on the walls and access) might be to mount blocks of 6 x 2 timber on each wall - using shield anchors (the big coach bolt type fixings) and mount joist hangers on the blocks to support the new joist.

 

[Anonymous]

David

Thanks for such a comprehensive reply! I follow what you say, and will try this solution. The three pieces bolted together will span the space and, more to the point, can be fitted into the available room.

Ross

 

[Anonymous]

Geoff

Did you mean a lap joint between the pieces to be bolted together? This was what had occurred to me, on reading your post. Thanks.

Ross