Pressure treated shed and wood protective treatment

AliceW

I was going to wait a few months and then use Barrentine Wood protective treatment on my new pressure treated log lap shed.(because I keep reading on-line that pressure treated dosn't mean it will resist water so the wood protector is necessary) but the men who came to put up the shed said that because it's pressure treated it doesn't need any further treatment. Any thoughts on this  would be great.

subjecttocontract

If it were me, I'd want a couple of coats of quality wood preserver applied as soon as it was up

FreeBear

I've slapped coats of wood preserver/sealer on all timber that sits outside, pressure treated or not. It helps to provide a consistent colour across the garden.

Effician

Not applied preservative/sealer to any pressure treated wood in 40yrs , best to let the wood breath & as i prefer the look of faded panels/ decking etc it's a win win as no extra cost & the wood last for decades.

subjecttocontract

Effician said:

Not applied preservative/sealer to any pressure treated wood in 40yrs , best to let the wood breath & as i prefer the look of faded panels/ decking etc it's a win win as no extra cost & the wood last for decades.

You have take the suppliers word that the item has actually been 'pressure treated' (as opposed to being dipped) and if it hasn't it'll be to late to do anything by the time you find out.

Albermarle

You can probably get away with not treating it further, but probably a good idea to give it a couple of coats, even if only after a few years.

Section62

Effician said:

Not applied preservative/sealer to any pressure treated wood in 40yrs , best to let the wood breath & as i prefer the look of faded panels/ decking etc it's a win win as no extra cost & the wood last for decades.

An oil-based wood preservative doesn't seal, so the wood can still breathe naturally.  Water-based 'paint'-type treatments differ, so you have to be more careful with them.

Decades old wood would last for decades with very litle treatment - but the rapidly grown stuff used in low-cost timber products these days is not going to last without thorough treatment and regular maintenance.

No matter what the shed manufacutrers and their installers might claim.

Section62

AliceW said:

I was going to wait a few months and then use Barrentine Wood protective treatment on my new pressure treated log lap shed.(because I keep reading on-line that pressure treated dosn't mean it will resist water so the wood protector is necessary) but the men who came to put up the shed said that because it's pressure treated it doesn't need any further treatment. Any thoughts on this  would be great.

Depends what "pressure treated" means.  "Pressure treated" is a method, like "painting" is a method.  The chemical used in the pressure treatment will determine the wood's properties, including water resistance.  Unless the shed company give exact details of the chemical they use for their pressure treatment then you rely on their word it is something effective.

I wouldn't take the risk, and instead would use an oil-based treatment like the 'Barrentine Wood protective treatment' you are thinking of. A couple of generous coats at least.

Effician

Section62 said:

Effician said:

Not applied preservative/sealer to any pressure treated wood in 40yrs , best to let the wood breath & as i prefer the look of faded panels/ decking etc it's a win win as no extra cost & the wood last for decades.

but the rapidly grown stuff used in low-cost timber products these days is not going to last without thorough treatment and regular maintenance.

When did these days begin ? as far as i'm aware most garden structure products have always been from rapid growing varieties of softwood. I can see no difference between the featherboards i used to make fence panels  25yrs ago 15yrs ago & last year.

What has changed is the allowed chemicals but even the modern stuff is still expected to last at least 15yrs & you certainly wouldn't want to burn it even after 30+yrs.

I would trust the pressure treatment far more than the claims on the side of a tin, obviously if a colour or always looking newish is you thing then oil based is the best option but i prefer the look of summer fruit & veg against mine while the sun is strongest  & have a clear fence that can breath in winter .

Section62

Effician said:

Section62 said:

Effician said:

Not applied preservative/sealer to any pressure treated wood in 40yrs , best to let the wood breath & as i prefer the look of faded panels/ decking etc it's a win win as no extra cost & the wood last for decades.

but the rapidly grown stuff used in low-cost timber products these days is not going to last without thorough treatment and regular maintenance.

When did these days begin ? as far as i'm aware most garden structure products have always been from rapid growing varieties of softwood. I can see no difference between the featherboards i used to make fence panels  25yrs ago 15yrs ago & last year.

I can't give an exact date as it is something which has been slowly happening over the last 30 to 40 years.  "Softwood" comes from a number of species. Then there are sub-species, and even within a sub-species the rate of growth and quality will depend in part on the location it is grown.

The rate of growth and quality also varies within an individual tree, typically young growth ('corewood'/'juvenile') is poorer quality than recent growth on older trees ('outer wood' / 'mature').  The first 10 to 20 years growth is typically corewood.

Given all those variables, you've been remarkably lucky to have a supply of 'softwood' for fence panels which has been so consistent through time.

In the past quality timber mills and suppliers would generally sell outerwood for structural and outdoor end-use, whereas the corewood would go for lower-end purposes such as manufactured boards (or for burning).  But with rising costs, and particularly with short rotation, corewood has become more readily available than outerwood.  If you are selling sheds to make a profit and don't care much about the quality then the timber you buy will be on price.  If you know the difference between corewood and outerwood and care about quality then you'd buy the latter, even if more expensive.  But you need to know the difference, and care about it.

Effician said:

What has changed is the allowed chemicals but even the modern stuff is still expected to last at least 15yrs & you certainly wouldn't want to burn it even after 30+yrs.

Agreed.  But that was the point.  You could soak poor-quality wood in creosote and it would last a reasonable amount of time.  Better quality wood would last longer anyway.  But consumers can't use creosote anymore, and may unwittingly buy poor-quality timber.

Expecting modern poor-quality timber to last without treatment in the way timber used to last is not a realistic expectation (for most of us).

Effician said:

I would trust the pressure treatment far more than the claims on the side of a tin, obviously if a colour or always looking newish is you thing then oil based is the best option but i prefer the look of summer fruit & veg against mine while the sun is strongest  & have a clear fence that can breath in winter .

Again, 'pressure treatment' is a name of a method.  Without a specification (e.g. reference to the relevant BS) the phrase is just meaningless words.  Like 'painted'.

I could put some wood in a chamber filled with water and (organic) food colouring, and pressurise it with a bicycle pump for 30 seconds, and then honestly sell it as 'pressure treated'.

Unless the supplier can tell you the specification used for the pressure treatment, and you can trust them, it is safer and wise to assume that the treatment is likely to be ineffective and needs further preservative treatment.

You don't have to trust "the claims on the side of a tin".  The best place for information is the product safety sheet - which will tell you what it contains in scientific language.  If you know what the contents are and understand (via internet research if necessary) what the chemicals do, then you can make a judgement on whether the product will be more effective than some undefined "pressure treatment".

And again, most oil-based preservative treatments don't seal.  Therefore the timber is free to breathe summer and winter.  And summer typically matters more because the changes in temperature and humidity tend to be more extreme (in the UK), even if the wood is shaded to protect it from UV.

Effician

Section62 said:

Unless the supplier can tell you the specification used for the pressure treatment, and you can trust them, it is safer and wise to assume that the treatment is likely to be ineffective and needs further preservative treatment.

Can't say i've ever bought pressure treated timber that hasn't had all the relevant info provided by the timber merchants or fencing suppliers & can't understand why anyone wouldn't check first.

I guess a lot of people will treat their new garden structures regardless & put the longevity of there structures down to their foresight when in reallity it's the correct pressure treatment process which is doing the preserving.

Tanalith /Tanatone is the tradename of the treatment currently used by the same merchants/suppliers i've used for 30+yrs & have every faith they know what they're doing.

Still have a few litres of original creosote but will save that for posterity as not really needed now.

I can't see us agreeing on this but at least it gives others a view from both sides of the fence