Building Steps Into a Slope

The layout of the slope may suggest two flights of steps at right angles, with a landing in between. On a long flight, make a landing after about every ten steps to provide a resting place. On flights with high, loose soil at the sides, you will need to build low brick retaining walls. The instructions given here are for steps built with brick risers and concrete paving slab treads, but the method is similar whatever material you use.

Tools: String and pegs; 5m steel tape measure; long length of timber; spirit level; builder’s square; spade; lump hammer; brick trowel; mortar mixing board; two heavy-duty polythene buckets and shovels (for mixing concrete); short tamping beam; pointing trowel or joining tool; earth rammer; 10mm-thick wooden batten. Possibly also a bolster.

Materials: Roadbase – one barrowload fills about 0.5 square metres at 150mm deep; concrete foundation mix; bricks: bricklaying mortar; paving slabs; bedding mortar; water. Possibly also sharp sand. Tools and materials are available from builder’s Warehouse.

Steps built into a slope

The ground is roughly shaped for the treads and risers. The first riser is built on a footing strip, and each following riser on the back of the previous tread. Treads are bedded on roadbase with a built-in drainage slope.

Building Steps into a Slope

Building Steps into a Slope

Fix two parallel stringlines from top to bottom of the slope, as far apart as the required step width.


Measure a line to find the length of the slope.


To measure the height difference between the levels, rest one end of a length of timber on the top of the slope and place a spirit level on it. Get a helper to hold the timber level while you measure the height of the timber above the lower ground level. If the timber will not reach the whole way, measure to a point halfway down the slope, then measure from the same point to the lowest level. Add the two heights together for the total fall.


Use the height and length measure­ments to calculate a suitable dimension for treads and risers.

Building Steps into a Slope


Fix stringlines to mark the front edge of each step. Make sure they are evenly spaced, and use a builder’s square to check that they are at right angles to the length lines.


Use a spade to shape the ground for each step. Begin at the bottom so you always have a flat area from which to work.


Dig a trench 125mm deep at the base of the flight to make a footing strip for the first riser.


Tip about 25mm of roadbase into the base of the trench and ram it well down.


Fill the trench with concrete, tamp level with the ground and cover it with polythene sheet.


Wait three days before building the first riser on the footing strip.

Building Steps into a Slope


Wait at least two hours for the mortar to dry before ramming down a layer of roadbase for the first tread behind the riser. Take care not to disturb the bricks and fresh mortar. Slope the roadbase surface to the front for drainage.


Lay paving slabs to make the surface of the first tread. Use a full bed of mortar and project the slab about 25mm in front of the riser to form a nosing. Bed the slab with a slight fall towards the front to allow water to run off.

Building Steps into a Slope


Build the next riser on the back edge of the first tread. Make sure the riser is vertical – use the mortar layer to adjust for the slight drainage slope on the tread.


Make sure the top tread is level with the surrounding ground. If necessary, slope the ground towards the tread, or raise the tread slightly – no more than 15mm.


Fill in between the tread slabs with mortar or sharp sand. If you use mortar, wait about 24 hours before using the steps, to allow the mortar to set.

Sloping a tread for drainage


Build up the roadbase surface a little higher at the back of the step. Slope the surface to level with the top of the riser at the front.


To check the slope, lay a spirit level from the back to the front with a 10mm-thick wooden batten under the front edge, on the riser. Build up the back of the slope until the spirit level is horizontal with the wooden batten in place.


Check that the roadbase area is level from side to side.


To save wear and tear on the lawn at the base of a flight of steps, lay a paving slab in front of the bottom step. Cut out an area of turf of a suitable size and depth, and bed the slab on a layer of 25mm-deep sharp sand.

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