Waterproofing
Bathroom & wet-area waterproofing
BestSeal AC408 Premium is a one-component nano-modified acrylic copolymer waterproofing coating; it is presented as a standalone system so AC407 and AC408 are not mistaken for layers of one build-up.
Public technical guidance
This page is selection and sequencing guidance, not a project method statement. The current product TDS, approved design, site assessment and trial application take precedence; structural anchors, cracks, water-retaining structures and other safety-critical work require qualified technical review.
Applicable for
- Bathroom and toilet floors and walls before finishes
- Showers, laundries and indoor wet areas
- Properly prepared concrete or cement-mortar walls and floors
- Areas requiring mechanical protection before tiling
Substrate requirements
- Surface clean and free of dust, mud, oil, grease, moss and mould
- Cracks and water-leakage points fully treated before application
- Final wash of the surface with a pressure water jet
- Saturate the substrate with clean water and remove standing water before AC408 Premium
Step-by-step procedure
- 1
Surface cleaning
Use suitable tools to clean the entire surface, removing dust, oil, grease, moss and loosely bonded patches; fill any voids where present.
- 2
Saturate the substrate
Spray the surface with a pressure water jet to dampen it and remove remaining dust; the substrate must be saturated but free of standing water.
- 3
Apply the first waterproofing coat
Stir the pre-mixed product and apply the first AC408 Premium coat by brush, short-nap roller or suitable spray at 0.5 – 0.8 kg/m², not exceeding 1.2 kg/m² in one pass.
- 4
Apply the second coat
Only after the first coat is fully dry, typically 6 – 8 hours depending on temperature, humidity and ventilation, apply the second coat perpendicular to it at 0.5 – 0.8 kg/m². Use at least 2 coats.
- 5
Inspection & protection
Inspect and rectify under the approved method. Mechanically exposed areas need a cement–sand protective screed after 24 – 48 hours; without protection, cure at least 7 days before use.
BestSeal AC408 Premium at 0.5 – 0.8 kg/m² per coat, at least 2 coats; indicative total 1.0 – 1.6 kg/m², varying with substrate condition and required thickness.
Common questions
Which waterproofing system does this bathroom page use?
This page presents a standalone BestSeal AC408 Premium system with at least 2 coats. BestSeal AC407 is an alternative cement–polymer system with its own method, rates and timings; do not default to applying AC407 and AC408 as consecutive layers.
What is the consumption rate?
BestSeal AC408 Premium is about 0.5 – 0.8 kg/m² per coat with at least 2 coats, an indicative total of 1.0 – 1.6 kg/m².
How long before I can tile or put the area into use?
Apply the next AC408 Premium coat only after the previous one is fully dry, typically 6 – 8 hours. Install mechanical protection after 24 – 48 hours; without protection, cure for at least 7 days before use.
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