Replacing joist ends

[alexakasloth]

Hi guys,
I have some joist ends that are in need of trimming and replacing on a suspended timber floor that rest ontop of a timber wall plate (also to be replaced). How would you go about securing on new timber to the ends?

I have seen a couple of methods, either by using L shaped "joist end repair plates" or by overlapping the timber by 600mm and using 5 x m12 bolts through at 100mm intervals. I was thinking the second method would be more secure and that I could also use some 5mm galvanized steel bar to make a pair of U brackets on the ends to increase strength.

Thanks for any advice!

 

[JBuk]

Depending on how many hoists and the size of them I would just replace them all, I did my dormer room and it cost a few hundred quid but they were quite big joists

 

[alexakasloth]

It's around 4 of them having pulled up the floorboards, they're 2x4 and the rotten timber is at the ends, decay is going back maybe 20-40cm (off the top of my head). I'd rather not take up the entire dining room floor if it can be helped.
Located by a radiator so possibly a leak there before?

I have also cleared out the air brick and any rubbish along there to ensure there's airflow.

 

[Slade2]

You have a number of options for repairs to be honest. Scarf joint some new timber ends. Splice joints (tend to be more specialist as you have to cut slots into the end and some steels are added and resin is then used to seal it all up and last of all you have the Repair plates as you suggested. Personally I don`t like repairs plates as its a bit of a cop out and can sometimes only move the problem further down the road as the rot continues down the timber. If you want my advice a good scarf joint is the way to go and it looks like you have a decent grasp of the problem and a solution. Also try and find out when they have rotted in the first place and try to look if there is any way to avoid that. Some pics might help

 

[alexakasloth]

Scarf joint looks good and looks like the way I'll go, I could also add some steel splints to reinforce as it's readily available pre-drilled for a good price.
I saw the resin system on a restoration website however epoxy isn't cheap.

I'll try and get some pics when I tackle it, won't be for a couple of months as I'm finishing off the kitchen at the moment.

[edit] I should add, the construction is a slate DPC with the wall plate laid ontop, wall plate and joist ends recessed into the brickwork. The joint will not be supported by anything underneath, hence why i'm inclined to use splints or reinforcement plates.

 

[jonzun]

Have a look at sistering joists, bolt through with timber connectors (looks like a ninja star thing)