On 18/11/2019 15:19, Steve J wrote:
Thanks, What do you think should be done with these pits in the sub
floor, which I assume are going down to the water table as they are
wet. Would filling them reduce the humidity.

Hard to say. They may be deliberate sumps to drain water out of the
cellar. One way would be to make a sump with a submersible pump and a
float switch so that any water that accumulates gets pumped out.

Don't delay if it is dry rot it moves at a fair clip and when you make
conditions drier so that it feels threatened it will create fruiting
bodies. Various sites have images of what wet and dry rot looks like.

It is confusing though as there are loads of wood rot fungi but only a
few of them are seriously damaging to structural wood. You may need an
expert to take a look at it to recommend the best remedial treatment.

The chemicals required to kill and prevent reinfection are not DIY.

Regards,
Martin Brown


On Monday, 18 November
2019 14:57:45 UTC, Tricky Dicky wrote:
The first thing you need to do is get the ventilation right. It is
possible to have the air vents below ground level but you need to
fit pipes large enough not to obstruct air flow and at the top the
pipes need to be angled and have angled louvres on the ends to
prevent water ingress. However this not your only problem as if the
patio level is above the vents it will also be above any damp
course level. You will need to excavate a trench along the
patio/wall interface below the the air vents by about two bricks
you can then put gravel in to act as a French drain, ideally with
some means of draining away although for a short bout of rain it
will simply drain into the soil.

As for the rot wet rot is the easier to deal with cut away any
rotten timber and replace. Dry rot is the bigger problem if it has
tendrils spreading across the timber then that is dry rot and you
need to cut back all affected timber at least 600mm past the
furthest extent of the rot. What remains must be treated including
any brickwork in the vicinity to kill off any spores. To be honest
it is a specialised job and I would recommend you get a company in
to identify the rot and if need be treat it.

Richard

There are some wet rots with tendrils too (not the most common).

--
Regards,
Martin Brown