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Plywood Baseboards

Written by Andy Watkins, 2001-2015.

Note (2023) This article was written long before the 16mm Modular group was formed.

One quick and easy way to build a railway in the garden is to make it out of timber. You can fairly easily bang some timber posts into the ground, and fix a plywood top to them, cutting the plywood to size and shape to get the curves you need. However, there are one or two things which you need to be aware of.

What sort of plywood?

First, there are lots of different sorts of Plywood you could use, some are better than others.


All plywood will bow unless properly supported. I have a set of baseboards made of 22mm Shuttering Ply, which are supported every 4 feet (approx 1.2m). Some of these are still straight after being left out untreated for over a year, but some are starting to bow, and need attention. Treated battens running the length of the board would help here, and something about 2-3 inches (50-75mm) deep will probably be enough.

Wood Preserver

Soak the boards in a perserver like Cuprinol for ten to fifteen minutes per side before installing them (to do this, you'll need to make a waterproof tray to do the dunking in).

Paint the edges of the plywood with a bituminous paint. It will stop the water seeping in, which could otherwise cause the plywood to de-laminate.

With wood perserver alone (i.e. no roofing felt), WBP is known to last for over ten years in a garden railway.

Roofing felt

Generally, you can improve the weatherproofing of a plywood base by covering the ply with roofing felt (a bituminous felt material covered in fine gravel).

Adding roofing felt to the armoury against the weather is a great trick. Not only is it exactly the stuff for keeping the rain out, because it's a roofing material, but it is also covered in little grey gravel shippings which pass for ballast or slate waste (slate waste is used as a sub-base material on some Welsh narrow gauge railways, being readily available.).

The aim with the roofing felt is to keep the wood dry, more than to keep the rain off. You will probably fix the track through the roofing felt to the plywood, thereby breaching the waterproofing in places. The bituminous material will close around the nails or screws to some extent, but if the felt is merely nailed or stapled in, there can be air pockets between the felt and the plywood, where water can gather. This problem can be minimised by glueing the felt to the ply with roofing adhesive. The stuff you apply with a heat gun or blowtorch is best (and hey, getting the blowtorch out is going to be fun! just be careful not to set fire to anything in the process!)

The roofing felt should be folded down the sides of the plywood to protect the edges of the ply, but should not be folded underneath, where it could allow more rain to gather. Instead, it should be left hanging down, allowing the water to drip off. A railway built using this technique has lasted over 15 years.