Joist damage

[daveaspy]

I've just taken up a solid wood floor that had been laid over a suspended timber floor. In the corner of the room there were several completely rotten floorboards (they just fell apart with a light touch). I think the main culprit has been a leaking radiator, but also the subfloor ventilation was very poor until a couple of years ago - all the airbricks along that wall had been covered. The rotten boards were very dry so I think this is an old problem that was fixed and the damage now just being discovered.

My concern is over the joist in the corner before I cover it up with new floorboards. It feels very solid, but the outside of it is a bit flaky. Is it ok for just the outside to be damaged? How bad does it need to be to have to be replaced? The joists are green so I guess they are treated wood which might have helped it resist the dampness?

 

[blup]

How old is the property (there looks to be some kind of membrane wrapped around the joist end)?

Are there any signs of fungal growth that could indicate wet or dry rot?

It's tempting to think that re-introducing ventilation and removing the old boards may have done the trick, but not really possible to tell just from photos.

Blup

 

[blup]

A leak from my old bath ate about an inch into the joist underneath , it was fine after removing the source of the leak and allowing the joist to dry out.

Blup

 

[daveaspy]

Thanks, there are no signs of moulds and the rest of the boards around look fine underneath. Hopefully all will be well then

Its a 1930s property but the joists were all replaced at some point as they all look nice and green and have their ends wrapped. Don't know when they were replaced, but at least 6 years ago as that is when we moved in.

 

[bobasd]

thats the remains of a remedial job by a damp and timber company.

has the floor dropped in that crner? any bounce?
the joist tails are wrapped in DPC material - its called capping-where they sit on masonry.
the green stuff could be a copper preservative spray.
it looks like that corner lacks ventilation. probly the cause of your problems.
are either oof those walls outside walls?where are the nearest air bricks?
if you remove the skirting on the right look at the back of it for rot.

if you probe the joists they might show decay. i always cut out all an any rotted joists but its your call.
remove all that decayed wood from the site dont leave any under the floor.
take out the rubble bricks as well.
the site earth looks very damp

 

[daveaspy]

That corner definitely did lack ventilation as the airbrick (just out of shot, 3 bricks from the corner) was both covered and not sleeved through the cavity. I replaced that a few years ago with a plastic air brick and sleeve.

All the skirting in the area was fine, no rot.

The earth under the floor is damp but not wet (the pictures make it look like there is water there!?), however we live in quite a damp part of the country with heavy clay soil so things don't drain at all well