Timber for polytunnel raised bed

[robgraham]

The farmhouse across the road is having some refurbishment with some outbui lding roof timbers being replaced. I can't at the moment get a close look at these (the owners are away at the moment), but I can see worm damage on one (common furniture beetle size holes in pine)

The size of the timbers would be ideal for the raised beds for the P/T I'm just putting together, but the possible presence of worm is a concern. I c ould treat the timbers but then that could leach into the soil - alternativ ely leave as is, but is 10m enough of a distance from my house ? Thanks fo r any comments

Rob

[Chris Hogg]

If the timbers are being replaced because of worm damage, the worm-holes and porosity of the wood would mean that the timbers will rot fairly quickly if not treated to prevent it. If you treat against rot you might as well treat against insect damage at the same time. What are you concerned about in particular about stuff leaching into the soil? Are you going to grow vegetables?

The air is full of bugs and beasties, including wood-worm beetles. I don't think it makes any difference whether you have those timbers close to or far away from your house; wood-worm are already out there, everywhere. So if you're worried about contaminating the soil, don't bother to treat the timber; it'll make no difference to whether you get wood-worm in your house, but be aware that the timber won't last.

Most timber for raised beds is pretty heavy duty. Old railway sleepers are popular, and they are usually heavily soaked in preservatives of one sort or another; you can also get brand new sleepers.

[fred]

building roof timbers being replaced. I can't at the moment get a close lo ok at these (the owners are away at the moment), but I can see worm damage on one (common furniture beetle size holes in pine)

'm just putting together, but the possible presence of worm is a concern. I could treat the timbers but then that could leach into the soil - alterna tively leave as is, but is 10m enough of a distance from my house ? Thanks for any comments

Modern centrally heated houses are anethema to woodworm. Not un-heated work shops as I found in my stock of Oak planks.

[Chris Hogg]

Wood-worm like a bit of humidity (such as you'd find in a polytunnel!).

Another thought for the OP. If he does use the neighbour's roof timbers to construct the raised beds in his polytunnel and he treated them against both rot and wood-worm and is still worried about contaminating the soil, after he's constructed the timber framework but before he fills them with soil, he could line the sides of bed with old fertiliser or compost bags. This would prevent the soil from coming into direct contact with the wood, and in that way reduce the migration of chemicals into the soil and possibly keep the wood drier and less likely to rot.

[robgraham]

outbuilding roof timbers being replaced. I can't at the moment get a close look at these (the owners are away at the moment), but I can see worm dama ge on one (common furniture beetle size holes in pine)

T I'm just putting together, but the possible presence of worm is a concern . I could treat the timbers but then that could leach into the soil - alte rnatively leave as is, but is 10m enough of a distance from my house ? Tha nks for any comments

orkshops as I found in my stock of Oak planks.

Many thanks Chris. Couple of excellent points there - beasties everywhere regardless, though I did think that the 'common' woodworm was a beetle and not a flying variety.

Your lining with fertiliser bags is good too.

The timbers came from the farmhouse garage that's been converted into a bio mass boiler room. The wall head ties had to be raised so were replaced.

The boiler is an impressive bit of kit - I just hope that it is reliable, a nd is not too expensive to maintain when it does go wrong !!

Rob

[stuart noble]

I think you'll find that lining with plastic bags will promote damp, and accelerate rot.

[Chris Hogg]

Most beetles fly.

And having the timbers in contact with damp soil would be preferable? I don't think so!

[stuart noble]

Damp soil usually becomes dry soil in fine weather, whereas moisture trapped behind plastic stays there forever. If that wasn't the case, you could wrap a the base of a fence post in plastic and it would never rot.

[Chris Hogg]

The OP is talking about a raised bed in a poly tunnel, where he presumably will be growing stuff all year round and keeping the bed moist all the time. The polythene bag lining would only be on one side of the timber frame, between the soil and the timber, and not totally enclosing it. The timber would stay dry naturally by evaporation from the open side, and moisture would not be replenished from the soil side, whereas it would be replenished if the timber were in direct contact with the soil.

It's up to the OP of course, but if it were mine, I'd use a polythene barrier.

[stuart noble]

I think I might use breeze blocks instead of timber. Not pretty, but functional :-)