Meoww wrote

He's also wrong about Dry Rot. Dry rot is so called because (A) it
requires drier conditions than wet rots

Not actually true. You don't often find Dry Rot for instance as a
result of rising damp. It needs quite a fair amount of water to get
started. When it's off and running it can do with less...

Yes, that's my experience too. Poor wording on my part. The largest outbreak I
ever saw ocurred behind wall panelling in a historic house following a fire -
there wasn't a great deal of damage due to the fire, but the water from the fire
brigade's hoses took months to dry out properly. And when the walls were
virtually dry (c. 22%) there suddenly appeared a mass or mycelium. This was
despite opening up as much panelling etc as we could to ventilate and assist
drying.

(B) it transports its own moisture and attacks dry timber.

It certainly does...

That's why it is necessary to eradicate it, not just cut
off the source of moisture

If you remove the water source, it will die eventually, as will all
rots. It transports moisture via it's hyphae from the moisture source
to dry wood and continues from there. If the source dries up however,
so does the rest of it. It can't manufacture water from the
atmosphere.

I'm not sure this is true. I believe it can survive for hundreds of years in a
dry state. I also read somewhere that it survives in humid air, without any
other obvious moisture source. If you have any research papers or information
on that I would be very pleased to know.

In practice, of course, it is very hard to cut off every source of dampness,
especially in old buildings. And nobody whose livelihood depends on advising
clients or carrying out a dry rot eradication service is going to be able to say
"OK, now I've cut off all the moisture it needs no further treatment."

Also current research on treating by ventilation is inconclusive in my view -
certainly not conclusive enough to be able to recommend it to clients. Good
ventilation stunts its growth, but it then tries to "escape" from the fresh air
and move to less ventilated places. It can even spread in places that can't be
ventilated, like behind plaster, and I've heard of cases of it getting through
solid brickwork.

Peter