Cheapest way to set up raised beds/seating

[miffy]

Phase one of getting my garden back to looking like one, it has been a wasteland since the builders left.
Had the idea of putting two raised beds at the entrance to the lawned area that are high enough and wide enough to sit on.
They will be approx five foot wide, and about four feet deep.
These will be approx eight foot from the conservatory so thought they would be ideal to use as seating too and want them to look attractive as so close to home.
Any ideas on a suitable building material to make them from that will be sturdy and wide enough to allow folk to sit on them.
I will be making these myself and I will have a go at most things but not a builder by any long chalk.
Thank you guys.

[dogsbody]

Railway sleepers (not the old treated sort) should probably do the trick. You can top them off with something suitable to sit on or just plane them smooth.

Whatever you use don't make them too wide or the edges too wide or you will have trouble reaching the middle.

[Mikey]

I can help with the height. for a good seating height they should be approximately 460-480mm off the finished floor level. I have several raised beds made out of rough sawn 6 x 1 inch timber lined with the black plastic panels brick companies put between their pallets. mine aren't at seating height they are slightly shorter at roughly 400mm off the floor.

Filling them with some camomile makes for a lovely smelling seat.

The heights are from new metric handbook, one of the bibles to all architects and planners, that and neuferts. They are based on anatomical averages, so if you are a little taller or shorter than average please compensate accordingly.

[WillyNelson]

I replaced nasty brick edged borders with raised beds in our garden with the idea that they would make for useful extra seating. I used 115mm wide concrete blocks set two courses high on a 100mm bed of compacted harcore. This gave a height of about a 450mm. At the moment they're still bare blockwork but the plan is/was to render them & paint them white.

I'd also thought about sleepers but I think Mrs Nelson votoed them in favour of the render. I had found a place online where a job lot of new sleepers worked out at about £12 each.

[Hilary B]

Block walls would be cheap, remember to leave drainage holes (miss the mortar out of some vertical joints on the bottom row), not only for the benefit of whatever you grow, but also becauseif the water is too slow getting away it will push outward on your wall. I've seen a few where that got forgotten and it DOES cause it to crack badly after a few years.
For a more comfortable seat on top, get some marine (or at least exterior-grade) plywood cut to the right width (200mm, which is about 8 inches?) and put that on top of the block wall. Don't forget to sand down the cut edges, and you may wish to apply something like boat varnish for a smoother finish.