How to replace two joists?

[salnajjar]

I suspect that this may be a "how long is a piece of string" type of question, but thought I would seek the advice and knowledge of the group.

We've just had the structural engineer round and the good news is that I don't have subsidence. The bad news is that the two joists that run directly underneath the back are rotten as hell. These joists run between the two external walls at either side of the bathroom and one of them butts up pretty close to the rear wall of the property. Access to them from beneath is pretty easy as theirs currently no ceiling in the kitchen beneath them.

So, the question is, how hard a job is it likely to be for me to remove these two joists and replace them with new timber. Is it in the realms of DIY, or is it really a job for the professionals? I class myself as being fairly competent and unlikely to cut corners or do a bad job but still...

As always, thanks for any and all advice.

Seri

[Set Square]

It shouldn't be too difficult as long as there are no pipes and cables going

*through* the existing joists. If there are, you will have to re-route these - or disconnect them, and drill holes in the new joists for them.

The existing joists are probably actually built into the supporting walls - which can only really be done at the time of original construction. You can probably get a new joist into one of the wall sockets, but you'll have to use a joist hanger at the other end. You can bolt this to the brickwork, after making good the existing hole.

[John Rumm]

Yup I would agree, it sounds eminently doable....

Set Square wrote:

You will probably need to take the floor up above them as well. If it is a pain to do that then you can probably still do it, but remember that the boards above may be nailed to the joist you are trying to take out.

[stuart noble]

Do you know why? If it's plumbing leak, try your buildings insurance.

[Rick Dipper]

What I would do is think it out, step by step, for example

How to I hold up what is there when the joist comes down ...

How do I get it down

How do I put it back up again, how do I get a bit of wood longer than the gap into the gap ?

How do I stop the same thing going wrong again ?

If any bit looks too scarey get a quote, if quote looks too high, rexamine scariness ......

Personally I'd DIY it, but then I am DIYing a build, from foundations to roof, minus a few bits I am simply not any good at - plastering. DIYing floor joists was one of my first strutrial DIY jobs.

Rick

[Rick Dipper]

Not always necessary, if the joist comes down, you may well end up leaving the floor behind, then remove the nails, however the floor will make putting the new joist in harder.

[salnajjar]

Buildings insurance is what paid for the structural engineer to come out. As a result they're going to be digging out all our drains at the back of the house and relining them (different problem, but great as it means I don't have to deal with the sheer mass of concrete out there).

The plumbing in the house is shot to hell, the job for the new year after fitting the kitchen was going to be gutting the bathroom and starting from scratch. Basically, the seal around the bath went a long time before we purchased the house also the overflow wasn't sealed correctly, this has caused the timber to rot, causing the bath to sink slightly, making the seal even worse, etc etc.

I'm just unsure whether I want to make two claims at the same time or let building insurance deal with the bigger job and I tackle the smaller one myself.

Seri

[bigcat]

Very valid point - I'd work out what it'll do to your premiums and for how long. Its often cheaper not to claim.

Joist replacement is a fairly straightfoward diy job if youre a generally handy person, read and understand the job first, and you appreciate that the load on the floor must be supported, and in this case jacked up slightly, by a prop (aka lengths of 2x4 about 2" longer than floor to floor height).

And NEVER let anyone fill the bath with the joist gone! A falling bath can kill.

If its a modern build it just might use high grade timber, such as C24, but probably not, just C16.

Finally, if someone is genuinely incompetent they could cause a serious accident, so a) ensure you know what youre doing first b) legally I dont recommend doing anything. Sue the other posters ;) NT