Fixing plates and joists

[chriselevate]

I have had issues with deflection in 2 rooms and in both cases I've replaced the plates and whole joist (where effected).

I have the same thing happening a the front door so have puled up the boards to do the work. In this situation I'm not going to replace the whole joist so I wondered what the best cure would be?

Here it is:

I can jack up the floor and replace the plate with treated timber and I'll make sure it doesn't touch the external wall (front of the house) and also lay it on a sheet of DPM.

If I sister the new piece of 4 x 2 treated timber to the joist (obviously cut off the effect part) how much overlap would you suggest and would you suggest nailing it to the existing one? What sort of nails would you recommend and what formation?

Thanks for any help and advice you can give

 

[catlad]

Your plan sounds fine don't use nails use 80mm screws. take up a couple more floor boards up so you can sister the joists a bit more and I would get a couple of bricks to pack up the centre joist were it has been spliced, just for a bit more support.

 

[chriselevate]

Brilliant. Thanks for your help. Sometimes it just needs confirmation and support before I go ahead usually.

When you say 80mm (3inch screws) would you advise something like size 8 or 10 etc? Would you pilot the a bit first to get them started and to make driving them in a bit easier?

When you talk about using bricks to pack it up, would you use sand and cement or just pack them without? Any DPM needed here?

One last thing... where the plate sits... I think I'll find I'll need to remove the old mortar and bed the new plate on a new bed of mortar. What mix would you use for this? Sharp or rendering sand with 4:1 mix?

Thanks

 

[catlad]

You can use bolts if you like and a concrete blocks instead of bricks, a piece of slate for a dpc its your choice, you have the general principal.