We used 50mmx150 mm treated softwood in 1.5 metre lengths (which is short enough to give the impression of curvature from a distance when arranged along a bend. Straight sides would be unsightly).
We ordered it from a yard, Nelson Potter near Ipswich, which was able to re-treat it under pressure after cutting to length from their 3 metre stock, so there was no need for extra protection for the cut ends.
The treated timber was claimed to last for many years in water and to be non-toxic to wildlife.
Oak posts (recommended by a contractor) were too expensive. We used:
- two 1.2 mx50 mm round pointed softwood stakes for each 1.5 m section
- larger 1.8mx75 mm stakes for the deeper sides, driven in with a heavy fencing sledgehammer (a maul), after tapping in with a club hammer.
- The treated stakes were so cheap that if they proved not strong enough they could easily be doubled up or have larger ones driven in alongside.
The hessian sandbags for the concrete were bought on Amazon. We used a dry mix of 5 sand and 1 gravel to one standard cement.
The following were the main costs, totalling £1,967:
Pumping £124 Submersible pump from Screwfix £56, 22 metres of pipe £40, heavy duty extension cable £28).
Timber £825 128 planks 1.5m x 50mmx150mm; 80x 1.2m x50 mm pointed round posts; 6 x 1.8m x 75mm ditto; 4 peeled pine sleepers 2.4 mx50mmx100mm
Digger £400 One day’s hire with operator, after £100 discount because job was finished early.
Concrete and gravel £470 Sand (3×1 ton bags), gravel (1x1ton bag for concrete, 3×1 ton bags for gravel path), 12 bags cement, 140 hessian sandbags
Tools £45 Lightweight aluminium shovel, fencing maul.
Sundries £103 Including geotextile (14mx1m), plastic pipes and joints for repairing drains from gutters to pond, cuprinol.