Replacing first level joists in tight area

[Paulie80]

Hi, an 80s dormer conversion was added to my bungalow and i'm in the process of making a section of it into a bathroom. The floor had some bounce and squeaking and I planned to sort this. The issue was clear with 6x2 joists being nailed into the 95mmx38mm ceiling joists. The nails werent fully secured and all could be rocked from side to side. 4 of the 6x2 joists had be cut which added to the bouncy'ness. The ceiling joists are solid. 

 

I've taken the cut 6x2 out and plan to replace with 7x2 I have left over from another project. The issue I have is I cant disturb the ceiling below and the gas/water pipes on the right mean I cant get a full length into the wall holes on the left.

My plan is the use a ledger board/wall plate on the left for the 4 new joists. Slide the joists in first on there side to fit under the pipes and then fit the ledger board which the joists will hang from. Have the nodding also attach to the ceiling joist to lock everything together. On the existing 6x2, use m12 bolts with square washers to secure properly. On the right is a wall which the joists will sit on. Below is my plan.

I appreciate this isnt ideal, wondering if anyone has other suggestions? Thank in advance. 

 

 

[Nickfromwales]

Hi. 

I've recently done a 16th century cottage bathroom and the floor was like a piano keyboard, as you walked the floor deflected downward at each joist.

Then ensued the biggest pig of a job you could wish for, getting it solid and level enough to be converted into a quality ensuite with bath and wetroom shower area.

I sister'd the biggest timbers I could get in, but on both sides where it needed it, glued and screwed to death with zero nails used ANYWHERE!! You can park a car up there now.

Do all the strengthening work, then get an electrician to drill the joists to re-route the cables, and then lay 22mm P5 deck, again glued and screwed, and you'll be fine.

It's a LOT of work to do these properly (retrospectively) and I did have to re-do some of the plumbing tbh, but you get out of things whatever effort you put in.

Good luck!

[saveasteading]

6 minutes ago, Nickfromwales said:

an electrician to drill the joists to re-route the cables, 

Not you obv @Nickfromwales 

 

Never assume that an electrician or plumber knows how to drill through a joist.

The hole has to be at mid depth approximately. Holes or notches near the top or bottom reduce the strength dramatically. Plus being more vulnerable to fixings.

See photo as another example of what not to do.