Timber steps are best used in woodland and lowland locations, and on sites where maintenance can be done as necessary. Timber is not appropriate in upland areas where stone is available. Timber steps are also insufficiently durable for some coastal locations, where heavy use combined with severe conditions of slope and weather may result in failure of the timber.
Use pressure-treated sawn timber and stakes. Where home-grown supplies are available, untreated logs can be used for risers, and split oak or chestnut for stobs.
Timber steps must be built with care, to give a strong construction and good appearance. Always measure to ensure stobs are equidistant from the ends of the risers, use a spirit level for the riser, and finish the tops of the stobs neatly.
Stobs
These secure the riser to the ground, and can be square or round timber stakes, metal pins or angle iron. Avoid using more than two stobs for each riser, and always choose to use two longer rather than three shorter stobs. It is difficult to knock the third stob in exactly in line so that the stress is placed equally on all three stobs.
If two stobs are not sufficient to hold the riser without it bending, then the riser is not strong enough. If unsuitable timber has been supplied, or if a repair job is being done, put the middle stob on the inside and nail.
The stability of the stob in the ground is the most important factor in keeping the step secure. A stronger construction is made by nailing the riser to the stob, but this is not essential, as it can cause problems with the stob splitting. There is also the problem that there is not always space to nail from the inside of the step, and nailing from the outside requires using 125mm nails, which are difficult to use without splitting the stob. If nailing is done, always get someone else to support the other side of the riser with a crowbar, so that the action of nailing does not loosen the stob. Nailing may be essential in areas of high vandalism, to prevent the timber being removed.
General procedure
Normally steps will be built from the bottom upwards, but where access for materials is easier at the top, construction can proceed from the top downwards.
- Place the riser temporarily in position, and measure the positions for the stobs so they are equidistant from the ends. Keep to this measurement for the entire flight.
- Start the hole for the stob with a crowbar, to make it easier to get the stob vertical.
- Place the riser, using a spirit level to check that it is level, or that it has the correct cross-fall as required. Knock wooden stobs into position with a mell, or use a sledgehammer for angle iron or steel bar stobs.
- Cut off the tops of wooden stobs using a carpenter ’s saw, and treat cut ends with preservative.
- Backfill steps and tidy site (see below).
Square stobs
Use 50mm x 50mm timber. The length will depend on the type of ground, but will normally be about 450mm. In ground where stakes can be knocked in easily, the step can be made stronger by cutting a 15mm notch, as shown. Weather the top of the stob. Do not cut notches for stakes in stony ground, as it will be difficult to get the stakes in exactly in line with the notches.
Always place the stake with the heartwood against the riser, as shown, as it is more durable than the sapwood.
The main disadvantage of square stakes is that it is difficult to knock them ‘squarely’ into stony ground. Often they twist slightly as they go in, leaving a gap which prevents a strong, close joint being made, and which looks untidy. Try starting the hole by working a crowbar across the ‘diagonals’ of the hole. Rounding the point of the stob reduces the tendency to twist. A stob holder can be used to help prevent the stob twisting.
Round stakes
These are easier to knock in than square stobs, as the alignment is not so critical. Use stakes of about 75mm top diameter, or larger diameter half-round stakes. Split oak or chestnut can also be used.
Steel stobs
Steel bar of 16mm diameter, reinforcing rod or other suitable material can be used, from steel stockholders or scrap merchants. Steel rods can more easily be knocked into stony ground that wooden stobs. For a neat finish, the risers can be routed in the workshop to accept the rods. Alternatively, the rods can be fastened as shown below. When used with railway sleepers, rods can double as carrying handles, pushed through existing holes, to ease the task of getting materials onto site.
Angle iron
This makes neat and inconspicuous stobs for sleepers or sawn timber risers, and in most situations will become hidden as vegetation covers the sides of the steps. Nail with galvanised nails. In stony ground, it may be difficult to accurately position the angle iron at the corner of the riser, as shown. If so, position as for other stobs, about 100mm in from each end, with the angle outwards. Do not nail.
