Twisted/Rotten Floor Joists - how can we support them?

wimbleQ

Good afternoon,

We have some problems with some floor joists and hope someone can suggest how we could solve it.

It is a terraced Victorian house. The room with the problem is ground floor and one side of it adjoins the house next door, the other is an external wall (garden is outside).

We've got some boards up and it's the ends of the joists which have rotten - they are sitting inside the bricks of the external wall (but are about to fall off as the ends are so rotten).

Some of the joists have also twisted, we think this is due to the rotting.

Would it be safe structurally to cut the rotten bits off, but a concrete slab under all the joists and build a wall on this slab, under the joists to support them all?

So the wall would sit inside the external wall and under all the joists.

Then we thought we could sort of brace the joists with pieces of wood between each one to hopefully straighten out the twist.

We know the correct answer would probably be to replace all the joists or add new end bits into the existing brickwork but we either can't afford to do this or wouldn't be able to do this ourselves, but the wall option is something we could do easily and relatively cheaply.

But we don't want to do anything that would affect structural integrity of the house - so if there is anyone out there who could comment on our proposed plan of action we'd be really grateful. We think the wall option should be much stronger and better than the current situation as some of the existing ends are just hanging on by the barest bits of wood and the floor itself was very springy and moving when walked on.

Ta muchly!

thebaldwindowfitter

yes you could do that make sure you use dpc under the joists

wallbash

Trying to get this clear, you planning to cut off the rotten ends ( that sit on/in the wall)
Then build a new wall beneath the ends to support the joists??

Can’t see that working. Bet when you start cutting the joists back to solid wood you will have removed a lot more than originally thought.
Forget wall, too much hard work.
Cut out rotten wood and bolt new timber to the joists to reach wall

wimbleQ

Hi A6 Windows,

Thanks for your reply - do you know what sort of "dpc" we should use? Is it the black sheeting type and would we just cut a strip of this and run it between the wall and the joists?

If I've misunderstood please can you give some more info on this?

Ta muchly.

molerat

wimbleQ wrote: »

Hi A6 Windows,

Thanks for your reply - do you know what sort of "dpc" we should use? Is it the black sheeting type and would we just cut a strip of this and run it between the wall and the joists?

If I've misunderstood please can you give some more info on this?

Ta muchly.

http://www.screwfix.com/prods/11557/Building/Damp-Proof/Damp-Proof-Course-112-5mm It comes brick width on a roll.

27col

Your symptoms sound suspiciously like dry rot. I had the same sort of rot in my first house and had to remove the floor completely and lay a new one. You can quite often tell if a floor joist has dry rot by feeling underneath it. If the bottom of the joist is concave(hollow) this is indicative of dry rot in the joist. If it is, then replacing the ends will be useless, as it the rot will re-infect any new timber. I hope it is not dry rot, because if it is, then it is a much bigger problem than you think. I suggest that you Google "dry rot" and see. There is a lot of information out there. It seems to spread by spores and the walls need to be treated as well. I remember that we burned ours with a blow torch to kill all the spores. As I have already said, I hope that you have not got dry rot, but make sure that you establish what sort it is, before wasting money on ineffectual treatments for the wrong problem.

Doozergirl

If you're ever going to sell this house, you're going to have issues trying to explain to a surveyor and subsequently your buyers how you've supported the floors.

Do it properly = do it once, IMVHO The joists aren't going to get younger when you've built a new wall to support them.

wallbash

If you're ever going to sell this house, you're going to have issues trying to explain to a surveyor and subsequently your buyers how you've supported the floors.

Even a full survey , you would not expect a surveyor to lift carpets and floor boards.
A simple 'jump' in the centre of the room will tell him enough.

aliasojo

Would building insurance cover this kind of thing or is that only for things like subsidence etc?

tomstickland

wallbash wrote: »

Trying to get this clear, you planning to cut off the rotten ends ( that sit on/in the wall)
Then build a new wall beneath the ends to support the joists??

Can’t see that working. Bet when you start cutting the joists back to solid wood you will have removed a lot more than originally thought.
Forget wall, too much hard work.
Cut out rotten wood and bolt new timber to the joists to reach wall

I can't think of any reason why it won't work.

However, replacement of the joists is the best solution.

thebaldwindowfitter

it will work depending on how rotten the joists are but replacement is a better idea