Basements are constructed below ground level and are therefore subject to ground water pressure. If insufficient external drainage or a failure in waterproofing, water ingress will result. The following information is designed for practical advice in three situations:
To secure basements, the best strategy is to ensure the water does not penetrate the building. Starting with construction the slab floor / wall zone requires a water stop for either tilt panels or block work. Another defence is to include crystalline growth compound in the concrete pour of walls or as a fill in block work. Once walls are constructed, secure them by ‘tanking’ with a liquid applied membrane. Then to protect the membrane, install a suitable barrier prior to backfilling. Essential to the defence strategy is good drainage, for which there are many design options.The final consideration in basement construction is to allow sufficient ventilation.
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Existing walls which have moisture or water penetrating internally, require treatment from the ‘negative side’. The two most common strategies is to either treat the brick, block, mortar with a crystalline growth treatment to stop the water, or to form a new barrier on the surface. Both methods are valid, but results will vary by situation.
FLOOR JOINT REPAIR
The most common failure occurs in the floor/wall joint. Depending on circumstances, the water needs to be managed or stopped by repair. To repair from the ‘negative side’ usually requires mechanical assistance to penetrate the surface. If it is a rising damp issue, form a line barrier through damp coursing. Mortar or cracks can be repaired with crystalline growth treatment. Whilst weaknesses in the slab or wall can be retarded via forming a new barrier on the surface.