Thread: Chances of old house stumps and fence posts being treated with chemicals?

Originally Posted by Mobyturns

Not to mention all the proprietary brands - like Tanalith. I've added a link to the Hemel SDS for Tanalith to highlight the cocktails of chemicals used for wood preservation typical in many of the brands used. https://hemel.com.tr/Data/EditorFile...nalith-SDS.pdf

Almost all wood has been "treated" in some form against insect or other biological degradation, from a simple spray with Borax in boutique mills, to complex high pressure treatment, dockside fumigation of logs (methyl bromide etc), heat treatments .... look up "International Standards for Phytosanitary Measures" and other regs - Ultimate Guide To Pallet Markings - Universal Pallets BITCON - Access Denied

There are heaps or regs - Timber Utilization & Marketing Act - approved preservation treatments .... restrictions on movement ...... yadda yadda

At least we have some idea at source from commercial vendors, but once it has left its primary processing origin anything could have been applied to it.

This issue is way bigger than I expected.

The questions that were in my mind when I started this thread are:

1. How deep did these treatments penetrate red gum?
2. What, if any, residue is likely to be in red gum 40 or more years after treatment?
3. Assuming that the top 5mm of the surface all round on a red gum stump or fence post is lost in the resawing process, is it likely that most or all of any residue has been removed?
4. What health hazards does the residue now pose to people resawing and reusing it?
5. What health hazards does the residue pose to people using things made of recycled red gum, notably things in contact with food such as cutting boards or in contact with skin such as chairs?

Originally Posted by 419

This issue is way bigger than I expected.

The questions that were in my mind when I started this thread are:

1. How deep did these treatments penetrate red gum?
2. What, if any, residue is likely to be in red gum 40 or more years after treatment?
3. Assuming that the top 5mm of the surface all round on a red gum stump or fence post is lost in the resawing process, is it likely that most or all of any residue has been removed?
4. What health hazards does the residue now pose to people resawing and reusing it?
5. What health hazards does the residue pose to people using things made of recycled red gum, notably things in contact with food such as cutting boards or in contact with skin such as chairs?

Answer to all questions - dunno & don't ask!

If you read older texts such as Bootle & Baker etc and old timber industry publications there is quite a bit of information about the efficacy of preservation treatments with numerous species, those that will accept treatment and those that don't.

How much to trim off - good question. Given that timber is a "porous" material with numerous vascular structures - depends!

Health hazards in use? another good question. On a similar topic many workers, home owners etc are now finding out that what we were once told was safe is now allegedly (???) killing off people exposed to those materials in the workplace, at home etc. Asbestos, engineered stone, creosote ..... DDT ....

As far as food safety goes, there are numerous "hazardous" products that are hazardous to store, transport, apply etc but once applied and fully cured meet the food safety standard requirements.

Originally Posted by Mobyturns

If you read older texts such as Bootle & Baker etc and old timber industry publications there is quite a bit of information about the efficacy of preservation treatments with numerous species, those that will accept treatment and those that don't.

How much to trim off - good question. Given that timber is a "porous" material with numerous vascular structures - depends!

Mobyturns

Generally hardwoods did not absorb much of treatments such as CCA and creosote. Those treatments were primarily used on timbers that were not class 1 durability and also had a thick sapwood, which did absorb the treatment. Spotted Gum is the best example of this as a commonly used hardwood that has a thick sapwood. Power poles were the main use.

Incidentally, when I mentioned creosote earlier, I should have said that it removes the skin's natural protection to UV rays: More technical than sunburn.

Regards
Paul

Another method used, before pressure treatment became the norm, was boiling creosote. Green posts were stood in drums of creosote over a heat source. As the sap in the log was drawn up by the heat, the creosote followed it, particularly in the outer sap wood.

Originally Posted by Skew ChiDAMN!!

A common old rural trick was to paint exposed timbers with a dilute mix of used sump oil. Often diluted with kero, ...

I'd forgotten about that, Skew.

Ay my old primary school in the 1950's they used to sump oil the floor boards during the August school holidays. When we got back, we had to put up with the smell for a few weeks until it dissipated, or we got used to it.

Originally Posted by 419

... pine is probably the most commonly treated timber because it's significantly less dense than hardwoods (in the sense of density rather than strict hardwood / softwood classifications) and responds best to pressure treating. ...

It is also about the cell structure of softwoods (pines).

You are right, pressure treatments do penetrate much further into pines than into hardwoods.

Originally Posted by rustynail

Another method used, before pressure treatment became the norm, was boiling creosote. Green posts were stood in drums of creosote over a heat source. As the sap in the log was drawn up by the heat, the creosote followed it, particularly in the outer sap wood.

RN

I once tried that process, but without specialised lifting equipment I realised how fraught with danger it was. I was trying to remember what the process was called. It was "something replacement" as creosote was drawn in by a vacuum effect.

I bought some treated hardwood from Bunnings a while back. That was a complete waste of time. About a year later I had to pull up some of the garden edging. In that short time it was already rotting through as the treatment was surface only. Much as I hate to admit it, the treated pine lasts longer even if it does split.

Regards
Paul

Sap Replacement treatment or SRT. Works well in sap wood inclusion fence posts and house stumps. The trick to it is to fill the drum with posts or stumps first, then add the preservative, then ignite the heat and bring to the boil. Not much fun trying to poke logs into a drum of boiling oil. This treatment is also referred to as Butt Treating where the level of creosote is only raised to the desired below-ground level of the posts or piers.

Originally Posted by Bushmiller

Mobyturns

Generally hardwoods did not absorb much of treatments such as CCA and creosote. Those treatments were primarily used on timbers that were not class 1 durability and also had a thick sapwood, which did absorb the treatment. Spotted Gum is the best example of this as a commonly used hardwood that has a thick sapwood. Power poles were the main use.

Incidentally, when I mentioned creosote earlier, I should have said that it removes the skin's natural protection to UV rays: More technical than sunburn.

Regards
Paul

Paul, my comment about how much to trim off was more about the face grain v end grain make up and as you also point out sapwood / heartwood. As the grain / vascular structures present differently they affect the take up of any preservative so it's not really practical or perhaps even true to say "take off 5 mm for face grain and 50 mm for end grain" with any confidence. With wood there are no givens and we've all seen exceptions.

I've had CCA treated posts, rails and pickets taken from the one pack of each, and presumably out of the same treatment batch (in both H3 & H4 class) that have had vastly different durability in use. Some of our CCA landscape low garden walls / borders have components that are over 30 years in service and others that barely lasted 2 years even though they are supposedly the same service / durability rating. I suspect that there is quite a lot of substitution happening, both inadvertent and deliberate.

One thing I find amusing is the concern about VOC's being off gassed from composite boards etc yet most new frame construction use LOSP treated timber -- ?????

Originally Posted by rustynail

Sap Replacement treatment or SRT. Works well in sap wood inclusion fence posts and house stumps. The trick to it is to fill the drum with posts or stumps first, then add the preservative, then ignite the heat and bring to the boil. Not much fun trying to poke logs into a drum of boiling oil. This treatment is also referred to as Butt Treating where the level of creosote is only raised to the desired below-ground level of the posts or piers.

This makes me wonder if old house stumps I've seen, which were probably installed in new builds from 1920s to 1950s/60s which were in pretty good condition below ground were treated rather than just naturally durable in ground.

Creosote doesn't seem too bad. It even cures toothache like magic, not to mention early tuberculosis ("incipient consumption").

Surprising it's not still available from your local chemist.




More at Calcreose

Originally Posted by Mobyturns

One thing I find amusing is the concern about VOC's being off gassed from composite boards etc yet most new frame construction use LOSP treated timber -- ?????

My limited experience with LOSP used externally as exposed (i.e. not under permanent cover from sun and rain) trim is that it's rubbish. I've done a few jobs where it's on a fairly new build and despite however many coats of paint the builder put on it has begun to rot visibly within 5 years or less.

Maybe that's because all the supposedly magnificent preservative has gassed out?

Even untreated meranti with a couple of coats of paint lasted way, way better on a house we built in the 1980s.

There can be some truly nasty stuff in old exterior use timber. The old timers put all sorts of things on it to prevent rot and insect infestation... They specifically wanted stuff that was persistent. Arsenic, lead, various benzine compounds, horrible pesticides, creosote derivatives, you name it. That stuff is banned now, but it was in common use 50 years ago.

Proceed with due caution.

Originally Posted by 419

That's an OH&S and legal liability nightmare. How long ago were Koppers doing this?

419

The time I was referring to was the early 80s. I don't know when the practice was ceased, but clearly somebody woke up and it is the reason it is no longer available. The way I found out about it's potential nastiness was I got a heavy splash of creosote on my work trousers and I did not change them straight away. The shift foreman saw what had happened and organised a change of clothes for me. However, the damage had been done. The next day I was playing tennis in the hot sun. About half an hour into the game I thought my thigh was on fire and I had to stop playing. The pain was excruciating.

I went to the chemist and got something to put on the burn. I remember I sat in the car to apply the lotion and the sun coming in through the glass windscreen was too unbearable. I had to move into some shade. I was working at the steelworks in Newcastle at the time and creosote was used as a fuel in the Blast Furnace.

It treated me to first hand (thigh) experience of the issue.

Regards
Paul