Replacing joists

[m0t]

Following on from my previous thread I've decided to just replace the joists and use slate tile to replace the rotten board they sit on.

Looks to be an easy enough process since the masonry pockets are quite deep.

Only problem is that one of the joists has a wall on top.

The wall is single story made of block work and built directly off the floorboards. There is a joist either side of the wall running parallel to it. Is there an easy way to support the wall and pull the joist or am I better off just sistering this one to avoid disturbing anything?

 

[Blagard]

Best put all the information on this thread. Usually a wall buit on top of boards will be non-loadbearing so you only need to support the weight of the blocks. However it cannot be assumed so it needs checking. Access could be a real problem so why not put some photo's or sketches up so that your description can be more clearly understood. Much could depend on how close the parallel joists are.

 

[m0t]

Thanks, I'm going to take the rest of the floor up at the weekend so will get pictures then.

The wall isn't load bearing, nothing underneath or above and the joists above also run alongside it and not on the top. The joists are spaced the same accross the floor (probably about 12 inches). The wall is closer to the joist I need to replace than the one I don't and probably starts about 3 or 4 cm from the edge of the joist.

Access is difficult because there is only about 3 inches from the bottom of the joist to the ground so difficult to get something else underneath to support.

My first thought was to support the joist then cut the end off and sister another piece alongside it directly under the wall.

 

[chappers]

Are you saying the wall is sitting along the length of the joist, if so just widen the pocket and sister it up

 

[m0t]

I have another question about replacing the joists - us it possible to get 'properly' sized ones?

The existing joists are 5"x2" and pretty much that size all the way along within a mm or so.

When looking for 5"x2" online the ones listed as that size are short on all measurements (commonly 47mm by 125mm). The width isn't a problem but the height is, particularly as some then list an actual size of 120mm which is 8mm short.

Am I missing something? Does anyone sell proper sized imperial joists, I can't be the only one with this problem?

Failing that do I just pack them up with slate?

 

[John D v2.0]

You just have to pack them to suit. Unless you buy rough sawn wood, it's all been planed down to an exact straight angle thus losing some millimetres. This is great unless you're matching old.
You can use rough sawn but it has a larger tolerance and you'll need to check the strength grading.
Our se said use hard wood Packers or steel, but the builders just used slivers of off cuts.

 

[m0t]

Well I don't think these were doing too much...



Only problem is that the joists run under the floor in the next room as well so I'm not replacing the whole length, just sistering new ends.

 

[m0t]

This is all that was left of the horizontal board they were sat on.



Aside from the high drive there was a lot of mortar piled against the base of the wall bridging the dpc along most of its length on the inside wall.

If these weren't running under the living room floor I suspect it would all have collapsed quite a while ago

 

[m0t]

How much overlap do I need between the old joist and new section?

I've got a load of radiator pipework right up against the last joist in the room and I'm thinking the easiest thing would be to cut the old joist before the pipe then move the pipes so they are behind the new bit of joist.

If I did that though I'd only have about 750mm of overlap.