new sleeper raised bed

Fire

A local school project which would like a new raised bed for their playground, around 1.5x1.5m. The spot is on asphalt on a gentle slope. I think wide sleepers would be great, so that kids can sit on the edge and the bed would last longer. But given the spot, the planter would need to have a base (not earth directly on to the ground). This seems a tricky combination.

Any design ideas would be welcome. Thanks.

(The drainage situs is fine).

K67

Few questions
How would you level up the sleepers If the bed is on a slope.
What the height would need to be to sit on it easily, although children are certainly more flexible!
The size of 1.5m is quite wasteful if your sleepers are 2.4 long.
You could probably use a geo textile as a base which would allow water through but not soil and could be stapled in once the bed is in situ.

Fire

My idea is for something like this - one of these, with a wooden base, lined, around 400-500mm high. It would have to be propped, as shown, to level from the slope. Possibly bought as a kit. It doesn't have to be sleepers, but something chunky that will last.

K67

They look very nice and I see they have levelled up with bricks under one edge but sunk into the ground for stability. Would you be allowed to do that?
You could use scaffold boards for the same effect but not as sturdy for sitting on and more fiddle to make.
Still use a textile base though.

Fire

"I see they have levelled up with bricks under one edge but sunk into the ground for stability. Would you be allowed to do that?"

No, it's on playground asphalt but less of a gradient. It's a good point about making it super sturdy to sit on over time; We could use slates or even bricks, if the gap is that big. I've asked my local garden guy to look at the project but all the good people in the area are booked up now until next year, a la lockdown.

K67

No chance of roping in handy parents?

Fire

We'll see.

Fire

I'm now thinking of going for a smaller bed and siting on the flat bit at the bottom of the slope. As mentioned, it's on an asphalt playground and I would want some kind of base on the planter. Do you think wood would be best on the bottom, then plastic lining, then soil? Or would membrane and a liner do. I'd have to find some kind of wood base after buying the planter.

I'm hoping this will be a long term installation, set up so it needs very little work from the various staff that come and go at the school.

Thoughts welcome. Thanks

Loxley

Why does it need a bottom, can't you just leave it open, cover the asphalt with a permeable membrane, then a layer of clean stone, then another membrane to stop the soil washing through?

If it's a very gentle slope you could probably get away with laying it flat on the ground (well not flat, following the slope if you know what I mean).

I would use sleepers laid on the flat side, which is sturdier and gives a more generous perch for sitting.

Fire

I would use sleepers laid on the flat side, which is sturdier and gives a more generous perch for sitting.

 Yes, it's an option. The slope is quite acute, so after a few weeks of reflection, I think it's easier to keep it on the flat. I will take a spirit level with me on the next visit. It's proving quite tricky to even get in and check on the site.

Fire

This is the current entrance way. The pots seem to be cast concrete and will be power washed and moved.

- - -

This is the thought for the new arrangement. The bed will sit under an overhang, which means it will need year round watering, which is a downside. I have taken the photo from higher up the slope.

There is dappled shade from large plane trees, west facing bed. I will leave a gap between the glass and the bed so people (kids) can sit there and there will be cleaning access for the window etc. The metal rail is only there to stop the door swinging to far out, as I can tell; It's not got access features or digital interface. It's a wheel chair accessible entrance way.

I'm trying to future-proof the project - trying to anticipate how it might get trashed, what happens if (when) it gets neglected (staff change) etc. Graffitti, cigerette burns, litter shouldn't be problem. There is strict access to this area, open to parents, staff and kids. I will ask for the staff to sweep it properly as part of the outside cleaning plan. That on its own will keep it looking better.

The area has never had a plan for it; all the planting in the school has been pretty ad hoc, I think, and bottom of the list of worries, but current staff are overworked but keen. Continuity of planting plans and their execution over the long term (decades) seems to the major downfall of most community / volunteer / school / green projects.