On 23 Dec, 19:20, "Brian G" wrote:
wrote:
On 23 Dec, 15:33, " wrote:
We have a cellar that holds water in our 180yr old house. I've
recently had to replace the bottom 3 stairs and the pantry floor
because the timber had rotted due to the water vapour when the cellar
fills up with water(approx 3 inch of water). Cellar is 7 foot deep
and until recently had no air bricks at all and the timber that
rotted had no doubt been there years so it lasted quite long.

I have installed 2 air bricks and replaced the floor and stairs with
treated(tanalised) timber. I used bitumen paint on the ends of the
timber where they came in contact with the damp masonry. This was
maybe 3 months ago and today I went down in the cellar and was rather
shocked to see that the areas of the timber that had bitumen on are
dripping with water and also there is white mould on certain parts on
the timbers?

Dear Mark
Are you sure it is mould and not fungus (not *mould)or
efflorescence(salt crystals? *If so take a picture and I will have a
look
To get a fungus after 3 months is not likely

Chris
PS
IF itis tanalised and has not been cut it is impervious to decay
c

-----------------------------------------

"To get a fungus after 3 months is not likely"

It is possible for timber to be infected with the dry rot fungus well within
three months - although unlikely with tanalised timber.

I have actuall seen new skirtings and window frames re-infected within that
time because a proper dry-rod eradication program had not been carried out
before their renewal.

"IF itis tanalised and has not been cut it is impervious to decay"

That is factually incorrect - tanalising only delays the onset of decay
(albeit for a long period and dependent upon local conditions) whether cut
or not.

Brian G- Hide quoted text -

- Show quoted text -

Dear Brian
Evidence please to support these two assertions?

I have been surveying houses for well over 40 years and prior to that
during my PhD studies carried out tests in a laboratory on fungal
degradation with a variety of wood-destroying fungi
I have seen such fungi ON tanalised timber and growing over it many
many times but it grows over it as an inert medium such as dry rot
grows over plaster or brick. I am happy to cite you papers where CCA
treated timber is tested from 4 kgs per cub m upwards to determine
weight loss (the lab test for decay) in comparison to untreated or
partially treated timbers and none show any decay. The main reason for
this is that the tanalith process chemically combines with the
hydroxyl groups on the timber as opposed to an active ingredient being
physically depositied and inhibits translocation of the heavy metal
irons that are the actual fungicides, So provided that the protective
envelope is not breached by cutting and that the loading of the
fungicide is in accordance with the presevation schedule the timber is
not only impervious to decay but also to leeching - the main precursor
of decay and also highly resistant to translocation of active
ingredient - another mechanism fungi have to overcome treatments.
Motorway fence posts are probably the most hazardous environment for
decay being buried in soil and these have a design life of a minimum
of 50 years. Any timber in a house is in effect impervious to decay
not being subject to the nitrogen supplement obtained when a post is
buried in the ground (e.g Baines et al circa 1976 ICST)

Wrt your
"It is possible for timber to be infected with the dry rot fungus well
within
three months "

This is quite accurate and I have seen it many time but of what
relevance is it to the posting? You are talking about RE-infecting but

Given the data in the posting
"...and the timber that rotted had no doubt been there years so it
lasted quite long.

IT is not dry rot and could not be in that cellar subject to flooding
as dry rot could not flourish in that environment - that is why
Coniophora puteana has a common name "Cellar Rot"!

Now I do not dispute that if you put new (untreated) timber into an
established attack of (dry) rot that you will not get SOME attack in
three months but that is not what I said and it was not the situation
that was posted. All the data support my view that for a new attack to
occur - that is timber to become wet enough from its initial mc of
less than 18%, for an appropriate spore to land on it, for the spore
to germinate, for the correct conditions of decay (oxygen, substrate,
water - the right % mc - spore or mycelium and the correct optimum
temperature) you would have a job getting a decent attack in 3 months
in a lab and would have to work at it hard let alon in a cellar in a
house where the chances are bordering on low to zero.

Happy to quote chapter and verse of all papers concerned to support my
statements and looking forward to your evidence in support of yours

Chris