Hi all. My son’s school has a nature garden that’s looked after by parent volunteers. It is huge and has chickens & composting & loads of cool stuff. But it doesn’t currently have a place where a whole class can sit & draw or write or work at once so it’s hard for teachers to use the space and they don’t bring the kids out here as much as they could.
I want to improve this set-up so it works better. There are three tree stumps, each 3 metres apart, for legs, with a long plank from a tree joining them, and several benches that are too narrow and tip over easily. I want to make the benches more sturdy and make a wider more useable table top but I’m not sure how to design something that will work. We have lots of old pallets we could use for wood and could potentially buy more timber. If anyone has any suggestions for a table top that would work & would survive being permanently outside that would be brilliant.
Also the bottoms of the benches are rotting as they’re just sat on wet ground. Options for the benches are to join them in pairs to make them twice as wide and more stable, or to add something wider at the bottom, or to just dismantle them and start again.
Hi Sarah,
Earlier in my career I was a furniture designer-maker so I know a bit about wood!
Permanently exposed to varying annual and daily temperatures, direct exposure to the sun, rain and frost there are very few timbers sufficiently resistant to rotting to survive for many years. if you think about it this is what naturally happens to a tree that falls.
I also spent a year working in a boatyard on the west coast of Scotland. Wooden boats come up against the same agents of destruction, though salt water deters certain kinds of mould.
The best defenses are;
Use wood treated with a fungicide/pesticide. You can buy Cuprinol or similar and apply it yourself to dry softwood (pine or spruce). What is more durable is timber described as or “Tanalised” - the timber is “pressure-treated” so the solution is been absorbed to a greater depth than is possible by brush application.
Use timbers that are naturally decay and pest resistant. These are teak, iroko and a few other tropical timbers that are expensive to buy so I doubt this is possible for you.
Design your structure to avoid moisture traps; joints, surfaces and features that will allow water to pool or where water will not drain off quickly (This includes broad horizontal surfaces. A plain flat table surface, though normal for interior furniture will not survive out of doors. this is why nearly every outdoor table is made with a slatted top - to allow water to run off, air to circulate and let it return to a dry state.
Apply protective oils or coatings. These can be oil or wax-bearing media that will reduce water absorption or paints that will form a water repellant coat.
Some pallets are made of pressure treated timber but not all and it is hard to tell if they have (a greenish stain is a good indicator). The other problem with re-cycling of pallets is that they are put together using annular nails which are very difficult to extract on account of ridges forged around the shaft of the nail.
If you have pallets that have a pair of large square-section beams running right across the width, and if you can extract them, they would make excellent “bearers” for a table top, which would be best constructed of a series of battens no wider than 75mm and of Tananlised wood. if not then buy some 75 x 45mm tanalised of lengths to suit the width of the table.
I can see that the simple benches are not ideal for uneven ground and as you say a wider base would help. Perhaps you could attach a pair of “outriggers” - elongated footings at either end (again, ideally of tanalised wood of say 75 x 45 section). They might make the bench more difficult to move but once a comfortable distance from the table is established perhaps they would not need to be moved that often. If the benches could stay put then lengths going from the foot of one bench across (under the table) to the foot of the one opposite would make them much more stable but again it’s a question of spacing them at an optimum distance from the table.
Using cut off tree trunks as pedestals is a nice simple solution, but in the long term these too will begin to decay. At this point it will be time to consider another solution to supporting the tops, but hopefully the tops themselves will be intact and a ready made component.
Hi Robin, thanks for your reply, that’s all helpful stuff. I will inspect the pallets a bit more closely to see what might be salvageable. The tree stumps are from trees that were growing there so will probably take a very long time to rot down. It does mean they can’t be moved closer together though, and the 3 metre stretch between each one is the bit I’m struggling with the most - I can’t figure out how to span the length, other than possibly an arrangement a bit like an upside-down railway track - two long pieces running parallel to each other with shorter boards going across them widthways, with gaps between them as you say to allow water to run off. I’m not convinced though and every join would get damp. Plus the ends could be splintery, and would be pointing directly at the kids sitting there. Hm…
