How-To-Build Walling

Guidance on how to install your new Anchor retaining wall products

Easy-to-build without the need for mortar or cement.

1. Excavation

Dig out a trench where the new wall is to be installed. This trench should be 600mm wide and 300mm deep.

Once you have finished digging out, firmly compact the soil in the bottom of the trench using a vibrating plate.

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2. Create a firm footing

Add a layer of crushed stone (such as MOT type 1, 20mm aggregate with fines – if you need advice, our sales team will be able to recommend a suitable product) then compact using a vibrating plate.

The final compacted layer should be 150mm deep and extend the full width of your trench. Make sure your footing is level front-to-back and side-to-side.

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3. Laying the base course

This is the most important step in the whole process!
Start at the lowest point on the wall. As you place each block ensure it is lying completely flat on the footing. To level the blocks you will need to dig out a small channel in the footing for the lip at the back of each block to sit into (Bayfield, Diamond and Aspen Stone only).
Place the blocks side-by-side, flush against each other. Use a spirit level to ensure each block is perfectly level.

Top Tip If you are using more than one bale of blocks it’s a good idea to mix blocks from different bales. This will help achieve a balanced blend of colours.

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4. Laying the second and subsequent courses

Make sure the top of the course that’s just been laid is free of debris then start to lay the second course.

As you position each block, move it until the rear lip (Bayfield, Diamond and Aspen Stone) is securely in contact with the block below.

Stagger each course in relation to the course underneath it so that each block overlaps the joins in the blocks below – known as a “stretcher” or “running” bond.

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5. Drainage and backfilling

Place a perforated drainage pipe along the middle of the footing. Generally the pipe should be placed as low as possible so that water drains down, out and away from the wall and into a suitable drainage system such as a soakaway.

Fill the block cores and all the gaps between the blocks with drainage aggregate then backfill behind the course you have just laid. Use a no fines aggregate – if you need advice just talk to our Outside Room sales team.

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6. Compaction

Add 150mm of drainage aggregate at a time then compact fully. The bed of drainage aggregate should extend at least 300mm from the rear of the wall. Place soil in front of the base course – then compact adding more soil as required until the base course is completely buried. Add more soil behind the drainage zone and compact. Continue to fill and compact as each course is constructed.

NOTE: If you are planning to build a wall taller than the recommended height, geosynthetic reinforcement will be required and you will need to consult a suitably qualified engineer.

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7. Finishing off

Secure a capping stone at the top of the wall using concrete adhesive. To ensure water drains away properly from the wall add and then compact a top layer of 150mm of soil with low permeability (a clay soil is ideal). Finally brush off any soil or debris.

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