Drainage

A drain is constructed terminating in a drainage pit equipped with a sump pump or alternatively to a local storm water outlet. The drain will be approximately 150mm into the clay base and lay a 90mm diameter agricultural drain wrapped in geotextile, which will prevent subsequent blockage due to silting. We remove the excavated material from site and backfill the drain with 20mm one sized aggregate to 200mm from the surface where the ground will be restored.

Drainage is also effectively used to divert water from an area of lateral dampness.

Poor or non-existent drainage can lead to excessive amounts of moisture reaching the sub-floor environs of the house. Here at FG James Pty Ltd, our professional and experienced soil engineers will propose a drainage system to divert water away from the perimeter walls of the property, decreasing the ground water flow to the sub-floor area and the surrounding footings.

LATERAL DAMPNESS

Lateral dampness occurs when the internal floor level is lower than the external ground level. Lateral damp penetration from the surrounding ground into the internal wall can cause plaster and brick damage through the migration of hygroscopic salts. Before drainage works are undertaken, the plumbing junctions should be inspected to eliminate them as a source of moisture.

In order to effectively drain and damp proof the walls from the positive side, the surrounding earth needs to be trenched 600mm wide down to the footings to allow sufficient working space.

After exposure of the sub-ground walls, our professional and reliable team of experts at FG James Pty Ltd will tank and seal the sub-ground section of the walls by brush application of cementitious membrane in slurry form to the brick faces of the walls. This has the combined effect of sealing any gaps in the brickwork and waterproofing in its own right.

After suitable priming, we will apply an elastomeric membrane prior to the installation of a geo-textile covered cut off drain plumbed to SW. The tanking will be protected with protector board and the trench will be backfilled to 200mm from the surface with 20mm aggregate and the original ground made good.