External & Internal Wall Leakage Treatment

This treatment is specified where the inspection shows it is the right answer for the problem found.

Where it applies. External facades, parapets, shear walls and the internal faces that show the damage — where the inspection has established that water is crossing the wall laterally, as opposed to rising from the ground or condensing on the surface. That distinction is made before we quote, because a facade treatment applied to a condensation problem achieves nothing and a chemical DPC applied to lateral seepage achieves nothing either.

Preparation. The cause on the outside face is corrected first: defective downpipes and rainwater goods, open pointing, failed sill and coping details, a planter bed or soil piled against the wall, or a neighbouring wet area on the far side. Loose and blown plaster is hacked off to at least 500 mm beyond the visible damp and salt line — leaving hygroscopic salts in the plaster means the wall keeps drawing moisture from the air and still looks damp after a technically successful repair. Cracks are cut out to a sound edge and filled. Where reinforcement is exposed and corroding at a spalled edge, it is cleaned to bright steel, treated and the section reinstated with a polymer-modified repair mortar. The substrate is then dried to a measured moisture content rather than to a schedule.

Application. The system is chosen against how much water is crossing and whether the wall needs to breathe. A silane/siloxane facade repellent — from about ₹35 per sq ft — where the masonry and pointing are sound and the issue is absorption; it repels liquid water while remaining vapour-open, so the wall can still dry inward. An elastomeric or acrylic exterior coating where there is fine cracking that needs bridging. A cementitious polymer-modified slurry where the substrate is poor. Where the outside face cannot be reached at all — a shared wall, a boundary, an adjoining building — a negative-side crystalline slurry on the inside, which resists water pushing against it rather than relying on adhesion. Two coats at right angles at the specified coverage in every case, with reinforcing tape at cracks and junctions.

Curing and redecoration. 4 to 24 hours between coats depending on system and weather. Replastered walls need to dry before decoration — roughly a month per 25 mm of plaster thickness. We state that drying time on the estimate, because painting a drying wall traps the moisture and the customer reasonably blames the treatment.

Testing and warranty. Moisture readings are recorded at handover and re-checked at follow-up, and where practical the wall is spray-tested on the external face. Eligible completed work carries Leakproofs by Betterwork’s written ten-year warranty on the treated area, with exclusions stated on the estimate.