Tim S wrote:

Lots of work at the Bungalow today. All went well, until this, though:

http://photos.dionic.net/v/public/bungalow/mushroom/

Wonder if the phots are enough for someone to be able to cast an opinion on
whether it's dry or wet rot?

These are the timbers underneath a lead flat roof, on the side of the
building (which is otherwise hipped roofed).

Looks more like wet rot to me - but how can I be sure it's not dry rot?

Yup I would agree - almost certainly not dry rot. None of the tell tales
like (fruiting bodies etc), no filaments with dripping water, and none
of the typical crazing/shrinkage visible where the wood shrinks and
cracks like a dry river bed as the cellulose gets digested.

If it's wet rot, then I can replace the visible section of wall plate and
one flat roof rafter (which is separate to the main roof rafters) and one
ceiling joist.

As long as you make sure no new water can get it, then that should fix it.

If it's dry rot, then I'm scared... Presumably that means new flat roof
time, due to having to cut back 2-3 feet from the affected areas?

Its not as scary as people make out... The main requirement is to cut
off the source of water. Ventilation helps as well. Cut away anything
obviously rotten and a bit beyond (2 - 3 feet is probably excessive),
spray everythign in the are with a decent dry rot treatment.

Looks like the water got into the inner wall leaf, then rotted the wall
plate from beneath.

Quite possible.

Found something similar in the under stairs cupboard here. 9" solid wall
with waterproof render over and no ventilation at the far end of the
cupboard (about 12' deep!) resulted in condensation on the wall. Since
the wall was impermeable, this just ran down behind the skirting and
into the floor, when it then tracked along the under side of the floor
boards until it hit the joist. It rotted a joist (which was also placed
parallel and too close to the outside wall), plus the end of another
couple that met it on sleeper walls.

My fix was to foam 50mm of celotex to the inside of the wall, replace
the dodgy bits of joist, and fit another 9 air bricks to help ventilate
the (substantial) under floor void - see if we can dry out the damp bits)

The planks supporting the lead seem solid and as you can see, not problems
at all at the other end, where the main hipped roof rafters sit.

Thanks *very* much in advance

In the words of the HHGTTG, Don't Panic!


--
Cheers,

John.

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