White mould on treated timber

[hoicem]

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?

Is this to be unexpected? surely the timber that I have put in will be better than the previous untreated timber.

[mail]

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

[Brian G]

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"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

[Brian G]

If the walls/air are as wet as you say then you can expect water to appear on the bitumen - the vapour will turn to water as it hits the colder surface.

if possible, can you take photographs of the problem and upload them to

and then post the relevant links here?

This will help to give a proper response rather than trying to guess an answer.

Also, if the water in the cellar is that bad, then you really should be looking to cure that problem before carrying out any repairs (other than emergency ones) and I suspect that the installation of two air bricks is not going to be anywhere near solving the vapour probem.

Brian G

[hoicem]

It looks like light white fluff. Like the kind of mould you see on food, it wipes off. It's on the surface of both the tanilised and bitumened timber.

[hoicem]

towww.tinypics.comand then post the relevant links here?

?pic=6q8vcsy&s=1?pic=7x3419w&s=1

[mail]

On 23 Dec, 19:20, "Brian G" wrote:

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 "... 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

[mail]

Look at it very closely - perhaps under a 10x lens and determine if you are looking at a biological mould or fine inorganic salts that just brush off Sometimes shining a torch at it shows the fine crystals of efflorescence and the brushing off makes it "disappear". If it is a mould there is likely to be a residual material where brushed off onto the floor. dificult to see in small quantities but try scraping it off with a knife onto black paper Either way you do not have decay problem Cure is to

1) isolate with a dpm off a brick pier 2) introduce such ventilation as to keep ambient mc less than 18/20%

If you do this the odd flooding will not cause decay

If it is tanalised I would not worry at all provided the endgrain is not cut where it abuts the dpm Chris

[mail]

towww.tinypics.comandthen post the relevant links here?

?pic=6q8vcsy&s=1?pic=7x3419w&s=1-Hide quoted text -

Mark Picy 2 looks like a mould as you say It does not have the characteristics of a wood-destroying fungus but it is impossible to be categorical as it could be the very early stages of inception I think it most unlikely in that environment I will check with a colleague who works more with moulds as to what it might be but the clue is that if it is forming on bitumenised timber it is likely to be mould from condensation and not a w-destroying fungus See earlier advice from me for fixing it

Best wishes

c

[hoicem]

towww.tinypics.comandthenpost the relevant links here?

Thanks, hopefully it is condensation. We've been doing a lot of plaster and cementing so there's been lots of condensation in the house. Before I redid the floor and stairs some joiners had a go and had used MDF and untreated softwood. That was on for a couple years with no ventilation and didn't show any signs of this white fluffy mould.

[Brian G]

All my working life repairing buildings as a carpenter and general forman.

To answer you the fungus question first:

I have supervised the renewal of joinery in a property that was severly infected with dry rot without first eradicating the damn stuff (against my direct advice) and within three months, the new timber was infected - after that little episode, my advice was followed.

You gave a sweeping statement that "IF itis tanalised and has not been cut it is impervious to decay".

That is untrue, I have seen rotten tanalised timber - and in fact, the life of such timber in certain circumstances is around 5 years.

A huge snip

Chris,

With all due deference to your knowledge (and I must admit I got bored with the length of your post and gave up less than halfway through [1]) timber is a living thing, and no amount of treatment by tanalisation (or any other method for that matter) will allow it to last forever - all it does is

*prolong* its life.

And that is from over 40 years of working with the damn stuff and not running laboratory experiments.

[1] Don't take offence at that as I have read the specifications/dissertations and listened to archtitects, surveyors, chemists and company reps spouting on about several different types of timber treatment over the years and taken a lot of the information with a 'pinch of salt' - especially when even the so-called 'experts' try to rubbish each other's claims.

And one of my joys was calling a rather arrogant rep back five years after using his firms so-called "guaranteed for ever" treatment, to show him a lovely piece of joinery thoroughly rotten and totally useless - that's life.

Never mind, have a nice Christmas.

Brian G

[mail]

On 23 Dec, 23:28, "Brian G" wrote:

Dear Brian Thank you for your wishes for Christmas. I asked for your evidence. As I see it your response was a) 40 years as a carpenter and general foreman on site [I have 32 years practical site experience as a specialist in control of wood-destroying organisms ranging from woodworm to fungi AND prior to that 9 years academic qualification both as a timber engineer and quite specifically in Fungal Enzymic Degradation of Wood with particular reference to Hemicelluloses] b)You assert without any EVIDENCE of scientific experimental data quoted that "..[1]) timber is a living thing, and no amount of treatment by tanalisation (or any other method for that matter) will allow it to last forever - all it does is *prolong* its life. " [The first sentence is factually incorrect - timber is a DEAD tree. OK so you meant it WAS once a living thing. You go on to say no amount of treatment will "allow" it to last "forever". This is quite true but IN THE CONTEXT OF THE POST is quite a ludicrous "argument" as the world is only likely to last another 4,000,000 years before it gets swallowed up by the sun and nothing lasts forever. What you meant by the term I cannot guess but suspect you mean forseable future in terms of mankind's history which would, say be several hundred thousand years[?} I was not making such a claim. I said it would be impervious to decay and my statement was limited to THAT HOUSE and THAT ENVIRONMENT cited in the post - namely a cellar subject to occasional flooding. Because I have studied the ~Tanalith process as a biochemist (my first degree) I have an understanding of the effect of heavy metal ions on the enzymes used to decay wood and uniquely in the wood preserving processes the tanalith does provide a chemical bond. It is thus more resistant to leeching that any other process as you cannot leach out an active ingredient that is chemically bound. Thus, your statement "...no amount of treatment by tanalisation (or any other method for that matter) will allow it to last forever - all it does is >

*prolong* its life..." is NOT correct in this situation. Of course it is correct in that NOTHING including the Earth lasts forever but that is simply not pertinent to this discussion. Such timber WILL last indefinately in a house that is irregularly flooded as there is no known decay mechanism that will attack such timber provided it has not been cut and the envelope of treated timber is there and contains more than 4 kgs per cubic m. I HAVE seen many cases of dry rot growing over such timber on site and can quote chapter and verse of experimental data to support the statement by means of accelerated ageing and weight loss tests of treated samples. So I have not only support from academic sources for my statment but also from my 32 years on site running a business repairing timbers in houses. 3) "And that is from over 40 years of working with the damn stuff and not running laboratory experiments."

The lack of laboratory understanding, let alone chemical knowledge is a limitation not evidence in support. The pejorative reference to laboratory experiments shows you to be NOT open minded and open to reasoned argument supported by data.

4) re "as I have read the specifications/dissertations and listened to archtitects, surveyors, chemists and company reps spouting on about several different types of timber treatment over the years " [I have a degree in biochemistry, four years of study specifically in timber degradation by fungi resluting in a PhD, two futher degrees one in timber engineering and was the first person to get credits in all three modules of the professional exam CSRT run by the Institute of Wood Science. I have lectured to these architects and engineers at the SPAB and to a certain extent agree with you that many if not most of the practicioners in the field (especially the salesmen) do not know what they are talking about but quoting their opinons as wrong should not let you fall into the trap of putting me in the same box as them.] 5)re "and taken a lot of the information with a 'pinch of salt' - especially when even the so-called 'experts' try to rubbish each other's claims. " Well at last we agree! 6)re "And one of my joys was calling a rather arrogant rep back five years after

Of what relevance to any of my assertions is this wholly predictable and quite true anecdote? None - you fall into the trap of conflating two separate issues.

I suggest it is probably that any experience you have of tanalised timber rotting on site (and you have not cited any) is due to cutting of the envelope rather than failure of the treatment. I rest my case.

Chris

[Pete C]

Tanalising has become a bit of an abused generic term to mean anything dipped in a vat of green liquid. It should mean something treated to the Tanalith process and spec.

Nevertheless, AIUI cut ends should still be treated so even the real deal is not totally fule proof.

AFIAK, the best preservatives are based on copper and give the wood a nice green colour. Most anything else will leach to some extent, especially from end grain.

Sikkens recommend in their bumph that joinery be given a coat of stain

*all round* before assembly, this would help minimise leaching (but adds a little to time and cost)

I usually give hidden surfaces a coat of water based stain, dries in next to no time if the wood has a low MC.

cheers, Pete.

[The Natural Philosopher]

Pressure treating only goes into the wood a few mm. (Sawn) end grain is completely unprotected by it.

[Tim Lamb]

In article , The Natural Philosopher writes

As are any cracks that form after treatment.

regards

[The Natural Philosopher]

Good point.