Dogged Timber Connector when Sistering Joists

[onabudget]

Hi about to sister some joists and use coach bolts through centre, do I need to use the dogged timber connectors between the two joists or will just the coachbolts and square washers be enough

thanks

 

[big-all]

much much better with timber dogs they prevent movement and the timbers act as one
having said that if the timbers are tight together and the load is not great then youll be fine but better with dogs no creaking or movement

 

[onabudget]

Thanks for that I managed to get the sister joist in however the existing has dropped over 80 years by about 1cm at 1/4 in from the end support where a block partition wall is build over the joists.

I have acro'd the old joist a little but the crown of the new sister joist means that I have had to acro the end of the new joist to get it into place (i.e. I have had to push it into position to combat (1) the crown and (2) the dropped old joist.

Is the fact that the new joist is already under compression a problem? or is this ok?

 

[big-all]

if your trying to spread the load they need to be fairly well ballanced load wise or they will counteract each other

would be better iff you can pack out the odd place to even the load

 

[noseall]

Is the fact that the new joist is already under compression a problem? or is this ok?

The tension betwixt the two will probably add to the strength.

 

[onabudget]

Thanks noseall and big-all for those comments It looks like the new joist will be slightly higher only by 1mm in places so I will stick on some DPC that will take up the gap and the new 22mm floor will sit on that.

I was going to try and jack the old floor more but the ends of the old beam started to lift from the bearing, so I'll try over the next few days a little more and then bolt it all together with M10 and square washers to spread the load at mid point every metre or so along of the joist if that sounds ok.

Have a nice weekend