Softwood outdoors

[sebmaster]

Hi,

Looking around it seems that softwood, as might be expected, doesn't fare well outdoors for long periods, however I can still find examples of it being used.

Is it possible to treat softwood so it is resilient enough to be used for large outdoor projects?

What kind of lifespan does it have properly treated?

Thanks!
SJ

 

[big-all]

get it from your local wood yard
ask for sawn treated[in stock]or planed/cls sizes that will need to sent off to be pressure treated and will take about 6 weeks including the drying time

 

[^woody^]

Treated softwood (ie Redwood) has a typical life of 20-30 years when exposed.

The main factors which determine its longevity are constant damp and UV - which breaks down the treatment and then the timber.

If timber is allowed to dry after getting wet, and if re-treated every few years then it will last a lifetime

Talking of softwood, Western Red Cedar is actually a softwood and that is one of the longest lasting timbers when used externally - even when untreated - 60-80 years ... as long as Oak

 

[sebmaster]

Hi,

Thanks for your replies! Looking at Red Western Cedar it seems especially cost effective when compared to the cost of a length of hardwood.

Why this preconception about softwood being unsuitable? Is it just because people consistently use poorer quality timber?

 

[Deluks]

As discussed, lack of maintenance. Plus any timber in contact with the ground, such as fencing gravel boards, will break down much quicker.

What is your 'large outdoors project' ?

 

[joinerjohn]

I have seen Victorian Barge boards on buildings, that have been original. Painted with undercoat and gloss , over the years. Surely , this is the best protection for timber externally?

 

[JohnD]

bargeboard are (supposed to be) protected from rain, though the backs can breathe

if rain gets to them then the paint will stop them drying out

for example I still have a few bits of Victorian fence that have not rotted, because although it gets wet in rain, it dries out very fast as there is no coating on it, so it spends very little time with the right level of damp and air for fungus to thrive. I could show you bits of Victorian window and door frame that have been well painted, but rain has got in through defects and they have rotted badly as unable to dry fast.

 

[sebmaster]

Hi,

The large outdoor project is a glasshouse, approx. 2x2x4m. I have a stone base (already built I am taking over the project) and I intent to complete it by building a timber frame.

The stone base is high so the wood should never touch the ground.

JohnD, I also remember in a previous house when we had sash windows replaced with double glazed units there was rot in the painted frames.

What about painting/varnishing the timber visible on the outside and simply staining the inside, protecting the timber from the elements but still allowing a large surface area to keep the wood dry should moisture penetrate through any defects? Or would it not be aired well enough inside?