Joist replacement

[TeaAndBiscuits]

Hi all,

Just renovating my upstairs bathroom (have another downstairs so time is not so much of the essence in this case, fortunately)

The upstairs bathroom seems to have suffered long term leakage (which was the reason that I had to pull down the kitchen ceiling below) due to the comically appalling way the shower was installed. Ripping up the flooring and removing the stud wall has revealed the extent of the damage.

I want/need to replace the patchwork quilt of floor boarding as it squeaks like crazy, is shaped like the surface of the sea and rotten in places. I have a load of Egger Protect board for doing this but I need to make the structure itself is sound.

One joist in particular is of concern. This one has been notched to about half its depth (LOL at the little metal strap screwed to each side!) for the old shower waste, has taken the brunt of the water damage and is pretty rotten and soft at the end. The rest are basically sound, albeit notched inappropriately in places.

What's the best way to repair this? Cut the joist back to sound wood just before the big half depth notch, then sister up a new bit with those toothed connector things and some bolts?

 

[Deleted member 174758]

TBH that joist is not only over cut, it also shows signs of decay. I feel the best approach would be to cut it out and replace like for like in size, C16 structural grade, but go for a treated timber and envelope wrap the other end with heavy roofing felt if it goes into a pocket in an outside wall.

 

[TeaAndBiscuits]

Right, spent some of my weekend getting this sorted. Ended up cutting 2 of the joists all the way back to the supporting wall (internal so no need for damp proofing) - the rotten one plus the one next to it which was quite badly twisted.

Repacked/reinforced the joint to the RSJ and added some noggings to keep everything square this time. Should be nice and solid now. Now to notch (in line with the rules this time!) and put the plumbing in and I can finally get some flooring down.

What a performance, this was meant to be a relatively simple bathroom refit job!

 

[catlad]

Funny how those small jobs always seem to take a long time!

 

[TeaAndBiscuits]

Funny how those small jobs always seem to take a long time!

It's expected with this house.

It's like one of those cars you end up with that every time you go to do some minor maintenance job or fix something you find someone has been there before and rounded off every bolt head, broken lugs and clips off and left bits out.

 

[StephenStephen]

...or the cork tiles on the wall we found behind the plaster we were going to tile onto!

 

[cdbe]

Looks a tidy job, but shouldn't noggins go mid span?

 

[Deleted member 174758]

How much was your overlap? Should be minimum 1 metre with 3 no. bolts

 

[TeaAndBiscuits]

They overlap where they are supported by a load bearing wall. 100mm each side of the wall (more or less)

As per the NHBC standards. According to this they only actually need be nailed together.

 

[TeaAndBiscuits]

Looks a tidy job, but shouldn't noggins go mid span?

Perhaps, and I may add more. Again the NHBC standards were my guide here. I do want to support the egger boards next to the wall anyway.

 

[Deleted member 174758]

We never nail them - always bolt them - and that's under written instruction from struchiral engineers. Certainly never been allowed to screw together by an S/E in probably 20 years

 

[TeaAndBiscuits]

We never nail them - always bolt them - and that's under written instruction from struchiral engineers. Certainly never been allowed to screw together by an S/E in probably 20 years

Well, quite. I'd be hesitant to just screw let alone nail them!