Retaining wall and seat

Retaining wall

Change function into feature by building your own retaining wall and seat, give your outdoor wooden furniture a longer lifespan in the sun, ensure sparkling water in your swimming pool and ensure you know how to get rid of pesky weeds in your lawn. A retaining wall can transform an awkward slope in your garden into a feature. Add a few elements to maximise its effect – we curved part of our wall and provided seating on the curve.

Retaining wall

1. Plot and mark your curve and wall on the ground with sand, mealie meal or spray paint.

2. For the curved seat area, remove any grass from the marked area, taking out a strip 600 mm in width. For straight walls with no seat, clear a 100 mm wide strip.

3. Dig a 200 mm deep trench where the walls and semicircle are to go, for the foundations.

4. Hammer a wooden peg into the centre of the trench near one end, leaving 200 mm of the peg visible. The cement for the foundation will be poured into the trench
up to this height. Continue knocking in pegs every half metre, checking that the tops are all on the same level as you go.

Retaining wall

5. Combine four parts stone, two parts river sand and one part cement with enough water to make a fairly wet mixture. Pour the mix into the trench and leave to dry for 3-4 days.

6. When the foundations are dry, build the walls using bricks and mortar. Lay a damp-proof course at ground level and reinforce the wall with Brickforce on every fourth course. Use a mixture of six parts building sand to one part cement, plus water, for the mortar.

7. For the semicircle, start at the front edge of the foundation and build a wall 500 mm high. For the straight sections, build the wall in the centre of the foundation, 500 mm high.

Retaining wall

8. Make the mortar 20 mm thick between the bricks. Create drainage holes every metre along the top of the first course of bricks by inserting lengths of the 20 mm PVC into the spaces between the bricks. Reinforce every fourth row of bricks with Brickforce. Using a spirit level, regularly check that the wall is level.

9. Keeping the same curve as the first semicircular wall, build another 500 mm high semicircular wall along the back of the foundations. When the space between them is filled you will have a seat measuring 500 x 500 mm.

10. Clean excess mortar from the bricks as you go to ensure a smooth surface for plastering.

Retaining wall

11. When the cement in the walls is dry, seal all brick surfaces that are not going to be plastered with Abe Brixeal or a product from the TITE waterproofing range. Brush on two coats, allowing 12 hours drying time between them, and then leave to cure for seven days before back-filling the flower beds.

Retaining wall

12. Fill the empty space in the seat with rubble and soil removed for the foundations. Compact it well with a stamper – you can make your own by sinking a pole into a paint tin filled with concrete.

13. Cover the fill with river sand up to 50 mm from the top and compact well. Fill the last 50 mm with mortar (six parts sand to one part cement, plus water) to finish creating the seat. This should be level with the tops of the curved walls. Leave the mortar to dry for 2-3 days before plastering.

14. To plaster the outsides and tops of the retaining wall, mix together six parts plaster sand with one part cement, plus water. Apply with a trowel and smooth around the edges with a float. Let the plaster cure for 21 days before painting.

The Gardener