Rotting wood in the walls...

[jester27]

I have had to take down the ceiling, and the plaster of the walls in my kitchen to try and deal with the effects of historic water leaks. As usual, this has revealed more problems! The house was built around 1922, detached with single skin. I have two main issues...

The walls originally looked ok, but the painted emulsion was blistering. My plasterer recommended removing the plaster back to the bricks, which I have done. This has revealed two previously blocked up windows (both small, filled with celcon blocks), and above one, the old wooden lintel is rotten. It is clearly doing nothing structural, as the mortar has also crumbled, leaving a good 1/4" gap to the bricks above. Do I need to replace this with a new lintel, or can I simply fill in the gap with a stiff concrete mix?


The second problem is also wood related! Having removed the ceiling, and exposed the joists above, I can see that a couple have a small amount of rot, at the base where the joist sits in the external wall. I noticed that the concrete render looked blown, and having taken that back, I can see that the joists are sitting on a piece of timber (about 2" high) set into the wall, which is thoroughly rotten. I can't see any structural purpose in this timber, so am guessing that this was used to level the joists. Again, can I fill this gap with concrete? I was planning to work in small sections, allowing the mix to dry, to avoid putting stress on the wall, but the wood is so soft, I suspect it is not holding much up anyway!

The joists I was planning to cut away the small areas of rot, treat and use joist 'sleeves'? to reinforce. Joists look around 7" x 2", about 17" apart, and the rotted areas are about 1" up from the bottom edge and 1" away from the wall...there are only a couple that appear affected, beneath a vanity unit that has clearly leaked in the past.

Any advice, cautions etc very welcome.

[stoneyboy]

jester27,
"Do I need to replace this with a new lintel, or can I simply fill in the gap with a stiff concrete mix?" Because you have solid walls normal gypsum plaster will not last too well. The wall needs to be stable so I would recommend you fit a new lintol from seasoned timber.
You do need to stabilise the ceiling joists and again replace the wall plate with seasoned timber and repair the joists by bolting new ones next to the old rotten ones.
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