Durable timber

[Billy Flitch]

This is not a rant just a observation, I think the people who rate the durability of timbers don't know their backsides from their elbows.
I can only surmise that they read about it in a book and then copy it into their own comments.
Just recently a couple of threads have been started with questions about durable woods and quite correctly IMHO members have directed them towards Larch, now when you look up larch it is described as moderately durable?

The people who sell wood make more money out of selling tropical wood than larch. Reading on one site it said "Larch used as a cladding should last 35 years and when treated correctly (what ever that means) should last 70, well I think that would see all of us out.

Now last week I was clearing a midden out at the bottom of the garden and I came across some wood the round wood I recognize from a job I did about ten years ago the wood on the left is larch and they have been in there the same amount of time.

When I looked at the larch I thought if that was sanded that could be used, by the way I don't intend using it its to small.
So here are two pics, one before I sanded it and one after it was sanded.

Over the years I`ve made windows, doors,Houses, barns, and boats out of larch and I`ve never had any complaints about it not one.

So 35 to 70 years moderately durable, makes you think what durable would be, probably pitch pine.

 

[Random Orbital Bob]

English Oak is my gold standard for outside use durable....HMS Victory springs to mind!!

 

[dickm]

I seem to remember that when York Minster roof was being rebuilt after the fire, oak was specified for the structure "because it was the only material proven to last more than 300 years in such a use".
But I'd still rate larch as being durable.

 

[blackrodd]

Larch, There's a blast from the past! It was a very popular timber once, here in sunny Devon, Excellent for exterior uses, rarely decorated or protected, but as you say, very durable.
Where I learnt my trade, Larch was used for gate and hurdle shuttles (rails), the upright being in oak,
I've cut out quite a few pairs of oars, and countless amounts of larch planking for boat building, etc
And until recently years, better and just as cheap as red softwood, My workshop is built of it, been up for 25 years
Sadly, the need for 12' gates for ever bigger machinery and the dreaded fibre glass etc have seen it's popularity decline.
Wood yards do sell it, I'm told, but it's nowhere near as popular as it was.
It builds a very good shed.
Regards Rodders

 

[RobinBHM]

There is a significant difference between European larch and Siberian larch. Siberian is much more durable, slow grown and therefore close grained and hard with a high tannin concdntration.

Siberian larch was apparently used in the piles for construction in Venice.

 

[Halo Jones]

I have just been pricing timber for a couple of gates. PAR joinery grade redwood came in at £123. Sawn, seasoned larch came in at £270!

I had really wanted to use the larch, and I know it would last longer, but the redwood gates will likely last 20 years if they are looked after and at prices like that I just couldn't afford the larch.

 

[Random Orbital Bob]

don't be looking at oak then!!!

 

[Woody2Shoes]

To be fair to those who may or may not know one of their body parts from another, I think that there is a significant variation - even if the species is [genetically?] identical - in durability due to how fast the timber is grown. As has already been suggested, other things equal, slower-grown with a tighter grain structure is probably more durable.

I'm told that, round here, coppiced sweet chestnut which has grown on a north-facing slope (thus more slowly) can command a premium price compared to that grown on a south-facing slope. I suppose the landowner also wants to be compensated for waiting longer for each "harvest"/rotation on a north-facing slope!

Why should a tighter grain structure make the timber more durable? Don't know, but perhaps more dimensionally stable (meaning coatings/treatments last longer), perhaps less ready to absorb moisture??

Cheers, W2S

 

[Random Orbital Bob]

Isn't it to do with density......the slower grown timber is more dense and therefore less susceptible to insect and fungal attack?? I'm guessing by the way, don't know if that's true. But I'm pretty sure that its chemical makeup is also part of it. Tannins for example, plentiful in oak are disliked by the bugs are they not?

 

[No skills]

I have some bits of old steel pallets that I think is larch. I have only run a block plane over 1 bit but it certainly cleans up nice.

I remember a grand designs where a couple had some larch (Japanese ?) trees felled and processed for their house build. I think they had a shock when the timber was graded, much stronger than expected.

 

[custard]

It's tempting to get gung ho about the resilience of specific timbers, but the fact is all wood rots eventually, just some disappears a bit faster than others.

UV rays break down lignin, the "glue" that binds the individual fibres together, so that alone will guarantee the destruction of any timber exposed to daylight.

I've recently been working with 60 year old Greenheart that was salvaged from a pier. Greenheart is fabled for it's toughness and durability so was often specified for marine use. Within the inter tidal range (so alternating wet and dry) it's badly rotten and worm eaten, permanently below the water is sound once the surface 15mm is cut away, permanently above the water is sound once the surface 25mm is cut away.

There's quite a lot of genuine Burmese Teak boards doing the rounds at the moment that were salvaged from a ship torpedoed in the first world war off the coast of Ireland, from what I've seen they're very badly rotten and worm damaged.

And both these examples are from Northern European waters, timber in the tropics has a much tougher time. I've seen lignum vitae, iroko, and rosewood logs with termite damage going deep into the heartwood. Any European timber left out in those climates would get chomped up in very short order!

Incidentally, a previous poster mentioned oak and HMS Victory. I've heard that the oak that was being sold a few years ago as "Victory Oak" was indeed oak and was indeed from the Victory, however it wasn't part of the ship when Nelson was on board! It was from Victorian restorations that had then rotted away again and been stripped out for a second round of restoration work. So oak certainly isn't a passport to immortality!