What to waterproof a garden sleeper with

kerri_gt

I'm about to replace some log roll which has rotted at the bottom with a softwood garden sleeper (we already have one elsewhere)

The raised bed that the new sleeper will make up is quite damp - its in a rather shady part of the patio and also water seems to pool that way when it rains heavily. The log roll was only put in a couple of years ago by us to replace some that had rotted through at the bottom (not put in by us) and now the same thing has happened to our roll.

The raised bed was there when we moved in, I have no idea what's under the soil, whether its patio slabs or just earth, so I don't know what the drainage is like.

Based on what has happened with the log roll, I want to waterproof the side of the sleeper that will be against soil but am not sure what to use.

Pond liner? standard heavy duty polythene which they sell on rolls at the garden centres or something else. Any advise would be gratefully received.

Davesnave

It's not something you can do with polythene. All you will do is trap what moisture gets between sleeper and polythene, and there will usually be some present. In some ways it may well be worse than doing nothing at all.

The best way to preserve wood is to pressure treat it during the manufacturing process, which is why some companies can offer 10 - 25 year guarantees against rot on things like fence posts. Even then, not all treatments are equal, so posts treated locally at the sawmill near me have failed after only 5 years.

With a softwood sleeper, you could paint it with some kind of spirit-based preserver, but this would not give much protection; certainly nothing like the creosote that used to permeate railway sleepers in earlier times.

I fear that there is no real solution to this. Untreated softwood will rot, but a sleeper's bulk will make this a gradual process.

kerri_gt

Thanks Davesnave - the sleeper I'm getting is treated so I guess it will be good for a while.

I did think a while back about removing the boarder completely, replacing the ground level with gravel and potting the plants that are currently there.

Davesnave

Shady and a bit damp is OK, if you enjoy some of the plants that grow well in those conditions, and there are plenty. Dry shade is harder.

I'd keep the bed, rather than pot the plants and add to my watering tasks, but it's very much a personal choice.

Potted plants can be moved around, including into the sunshine, if they look like they need a boost.

kerri_gt

I think the bed is going to stay for the moment, with a new sleeper. The clematis is definitely not portable. Both the clematis and laurel are growing well. Think the soil might be a bit wet for the Astilbe but at least it won't burn where it is in the shade.

Davesnave

kerri_gt wrote: »

. Think the soil might be a bit wet for the Astilbe but at least it won't burn where it is in the shade.

The National Collection of astilbe at Marwood Gardens, sits beside a stream and lake.

http://www.astilbecollection.co.uk/

wellused

When I am faced with putting softwood anywhere near to the ground I will paint it with bitumen paint even if it has been treated by the manufacturer.