Ground floor joist problem - new support?

[biglebowski2010]

Hi,

I’m doing work on my London terraced house that was built circa 1900.

The floor was quite bouncy and when we lifted some floor boards we discovered the joists have little or no support on one side, hence the bounce (there’s a small cellar on the other side of the joists so we can see that they are well supported on that end). On the side with the problem the wood that the joists were sitting on has rotted away to a large degree, but the joists themselves seem OK. This applies both to where the joists reach the whole way to the wall and where they stop short where a hearth for a fireplace used to be. (see pics). Has anyone got suggestions on what is the best way to introduce support for these joists again?

Some of the support beams that the joists were resting on seem to be sitting on bricks at certain intervals. Is it likely that these bricks are part of some kind of dwarf wall?

Any ideas on how to solve this problem would be much appreciated!

Untitled

• biglebowski2010
• 20 Nov 2008
• 1

Untitled

• biglebowski2010
• 20 Nov 2008
• 1

Untitled

• biglebowski2010
• 20 Nov 2008
• 1

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[GoingDigital]

Looks like there was no damp course so you are probably going to have to lay a damp proof strip and then put a new support timber down.

 

[Symptoms]

big - this is a really common problem and the fix is straightforward. You must cut-out any and all timbers that show any sign of rot and generally a decent way into the healthy stuff, then apply a good lick of a timber preservative, then introduce new treated timbers which are bolted onto the, now shorter, joists (you extend them). Clear-out (dig) all that debris to create good air-flow space below the joists and if necessary repair any dwalf walls. Any timber in contact with any masonary MUST be protected by, as GDigital says, a damp-proof course - this plastic stuff comes in rolls and is inexpensive to buy

 

[biglebowski2010]

Thanks for the help guys.

Are there definitely likely to be dwarf walls under the timber that the joists are currently resting on? It's difficult to tell at the moment. In some places there seems to be, in others it looks like there aren't any. If there aren’t dwarf walls already there what do the new support timbers need to rest on? Do we need to dig a trench and create a dwarf wall or something else underneath?

 

[gregers]

think it might be worth taking all the boards up and investigating all the floor before you start to patch it up,it could be a better job stripping it all out and starting again using some of the old timber as the plates etc.but this all depends on the state of the rest of the floor,if its just the ends do as suggested by others who have posted replys.