replacing joists and sole plate

[Wasted]

I have just bought a ground floor flat and have found a problem with two supporting walls in the bathroom.

GF Flat with one flat above. FF flat has same foot print and supporting walls rise to eaves level.

The joist have rotten along with the sole plate which supported the the joists and the brickwork. in several places a couple of courses of brickwork have slipped into voids left by the rotten timber. the cowboys have been in and done some pretty poor cover up jobs.

What would be the best way to replace the joists and re strengthen the walls?
As I see it there are three options albeit there may me more;

1 Strip out and replace the sole plate with treated timber and renew the joists build the wall up from the new sole plate.
2 strip out sole plate a build up using brick to make up the wall leaving pockets for the joists?
3 rebuild the wall using brick use galv joist hangers.

Obviously I will need to replace the DPC at the same time but my concern is primarily the strength of the wall

Any guidance would be much appreceated

Cheers

Untitled

• Wasted
• 15 Jan 2012
• 1

 

[gregers]

am i seeing another room of joists showing?
if so just wondering if it might be better to cut back the joists and build new sleeper walls either side of loose wall,so the wall becomes independant to the floors.that way the problem shouldnt arise again.

 

[Wasted]

yes the bathroom is between a living room and a kitchen.

The joists for for bathroom and living room are supported on sole plate of one wall and the opposing parallel wall supports joists for bathroom and kitchen

Regards

 

[joinerjohn]

I assume that this wall extends up above right through the flat above? Shouldn't be built off a sole plate, but should just have the joists built in to it. As gregers has said, it's probably a good idea to remove the joists and build sleeper walls alongside the re-instated wall.

 

[Wasted]

how close can the sleeper wall be to the structural wall?

The bathroom is only about 1.6m wide.

 

[gregers]

you may find when digging down the stepped footings?
when i do this i cut back 1 of the steps and build directly off of the orriginal footings.hope that makes a bit of sense,pics would help.

 

[hotrod]

I can't see any sole plate in those pics. That masonry is in a bit of a mess, not a big job for a decent builder but could be a bit of pain for a diyer. Take care if those water pipes are still in service because that brickwork looks like it might be bearing on it and could cause it to fail if it slips any further.......

Those joists look a tadge small as well.

 

[Wasted]

the wall plate has rotten and been bodged previously.

The joists are 4 x 2 and in the adjoining rooms they are supported by sleeper walls at aprox 5ft spacing.

If I were to change the joists up to 6 x 2 of greater then I would be replacing the floor level throughout or rebuilding all sleeper walls to maintain current level. Not really an option considering floor supports are sound in the rest of the flat.

 

[tim00]

1. With respect to the poster, dont go for the new-build sleeper wall(s) option. The wall below the joist tails is honeycombed for ventilation. Dont go blocking off the ventilation with a new sleeper wall. Lack of ventilation could have caused the original fungus infection.
2. If the joist tails are rotted out then cut them off 150mm past the damage.
3. Remove all wood and masonry debris.Spray the masonry and wood work with fungicide.
4. Work on one alternate joist, or joist bay, at a time.
5. Bolt-on same section joist pieces,say 900mm long. Or, if going back to the mid-way sleeper walls, ie.5ft away, then no bolt-on reqd. but pin new to old joist.
6. brick up to support bearing wall - slip in pieces of DPC, leave original DPC in-situ. No wall plate reqd. pack up to level with brick and slate.
7. Sleeve the pipework thro the wall.
8. Clean out all vents and add new vents if reqd.
9. Determine the cause of the infection.
10. 4x2 over a 5ft span will just about do - are they original sections?
11. Test new joisting for squeaks and sway before boarding over.

 

[Wasted]

pipe work is not an issue. These are all being re routed
I have checked Build regs Tables and the spans are ok even for replacement 47mm x 97mm c16 timbers.

I intend to spray all sub floor timbers while I have the opportunity.


Not sure I follow your logic about leaving the old DPC in place and not replacing the wall plate. in places the existing slate dpc has been displaced and to leave it would retain a loose joint. Secondly to make up the height between courses would required a course of cut bricks in order to maintain the floor level for the joists. On a bed of existing joint inc dpc and new bedded dpc joint. this would amount to a cut of less than half height brick.

 

[tim00]

You work from clean brick work ( no bed, no slate )for laying the DPC mat. and pack up from that. If you want to go back to a plate then go ahead - it will carry inherent risks of further infection. Use wide DPC

From your library pics a number of joists req total replacement.

Research historical Timber & Damp posts/issues in this forum.