Raised bed lifespan.

[Drawweight]

I had raised beds built 4 1/2 years ago out of 200 x100 timber.

I’ve just noticed they are starting to rot at the point where the soil stops.

Is that about the average lifespan? They’ll probably last years yet before they eventually fail tho.

In the event of them eventually having to be replaced what route should I take to avoid the same situation.

[xx99xx]

- sleepers
- composite decking
- wooden decking (treated)

[Sford]

I made some out of Horman section garage doors with large treated posts in the corners, routed to accept the door. Then covered the corners with some damp proof to try and reduce the direct contact in this area. Then put some nice decking around the top and painted the sides from white to a dark green barn paint I had left from painting our oil tank. Has worked well, lasted well and seems to be doing ok.

[Harpoon]

I've just built two new beds and replaced a knackered one. The knackered one was already built when we purchased the house, so I only know it was at least 10 years old. I suspect the sleepers used on that were 150 or 200mm thick but it wasn't lined. It was joined on the inside using metal brackets (flat and L shaped), so when some bits have rotted through, the screws for the brackets have nothing to grip and it was pushing apart from the inside.

In the worst places the sleepers were almost entirely gone but in other places, at least half or more of the sleeper was still solid. It looked rubbish but would maybe lasted another couple of years. This was the inside at one point when I started to dig it out:



For all the new ones I used 200x50mm treated planks and then lined with DPM from Screwfix.

[hidetheelephants]

The old man built a pair of raised beds with breeze blocks; quite a lot of effort but 15 years later they're as good as the day he made them. Being a lazy bd I think I'd try and adapt sections of concrete garage to avoid the bricklaying.

[wolfracesonic]

I’m assuming treated softwood at the sizes you give? Four and a half years doesn’t seem great but given their bulk it will be a while before they disintegrate altogether, think Titanic on the sea bed! I’ve read lining them with dpm helps but you need to make sure water doesn’t become trapped between it and the timber. Also make the timbers are treated to UC4 standard. Probably the best bet against rot is too use reclaimed tropical hardwood (jarrah/azobe) ones, I’ve had some in around 14 years, they still seem fine though they definitely have a rustic look to them that not everyone likes.

[8-P]

Expensive to make (no materials prices are so mental)

Then you need to fill them and that aint cheap either!

[OutInTheShed]

I don't want 'serious' biocidal chemicals next to my veg.

I've had to dig out and replace a bunch of log structures retaining a small bank, that was annoying enough, I think the logs were about 10 to 15 years old.

I've done some rustic planter things, using logs cut from my hedge, they look fine after 4 years. I lined them with polythene.

Timber stuff tends to have a short life in the West Country.
Stone or plastic is proper job.