Choice of brick
Although a well-designed retaining wall will feature details to prevent saturation of the brickwork, it is common practice to specify FL bricks i.e. bricks which are fully frost resistant and have a low salt content. This approach is recommended as a precaution against any failure of the waterproofing measures taken as this would make the wall vulnerable to staining and could even lead to sulphate attack of the mortar in areas where certain clay soils are present and the mortar is vulnerable.

Mortar and Jointing
Designation (i) or (ii) mortar is recommended, although, where there is a risk of conditions developing which are conducive to sulphate attack, sulphate-resisting Portland cement (SRPC) should be used. To maximise the water shedding properties of the brickwork, mortar joint profiles should not be recessed.

Drainage
The structural design of a retaining wall will be based on the load imposed by the earth to be retained; it will not take into account any additional load resulting from the development of a head of water pressure. Consequently, to ensure the structural integrity of the wall, it is critical to prevent water-retention in the earth. This can be achieved by incorporating a drainage layer granular material, for example - behind the wall, with land drains, and by providing weepholes at regular intervals in the face of the wall.

DPCs
To maintain structural continuity, a DPC must be constructed from engineering bricks at the base of the retaining wall. This should comprise a minimum of three courses of DPC Type 1 or 2 bricks, with at least two courses being visible above ground level. Insertion of a sheet DPC should be avoided as this would adversely affect the integrity of the structure, perhaps allowing a slip plane to develop and potentially giving rise to long-term performance problems. To minimise saturation of the brickwork, either a bitumen polymer DPC or a two-course tile creasing detail should be included near the head of the wall.
A waterproofing membrane or applied liquid coating should be applied to the rear face of the wall to prevent water and soluble salts in the retained material from percolating through to the face of the wall to cause disfiguring stains.

Coping and Cappings
For retaining walls, in most locations, a projecting coping with a drip throating is recommended. Whether a coping or a capping detail is selected, this should always be constructed using bricks or special shapes of FL designation.

Free Advice.
Most free standing and retaining walls are designed with individual requirements in mind, if you have any doubt as to the suitability of any of our products to your project please contact our sales office and we will be happy to advise.