1. Introduction
Isolated footings located in areas where the groundwater table is at or above footing level require robust below-grade protection. When no basement is provided, selected external coatings or membrane systems must resist hydrostatic and soil-borne contaminants while accommodating construction / execution constraints. This page standardises the typical systems, execution steps, QA and BOQ language for isolated footings with water table.
2. Area of Application
- Isolated footings (with cap / without cap) where groundwater is at or above footing level.
- External faces of the footing up to finish floor level.
- Pile cap / grade beams junctions adjacent to footing.
3. Technologies Considered
- Coal-tar epoxy based high-solids coating (documented primary system).
- Polymer-modified bitumen coating (alternative where specified).
- Supplementary systems (use-case specific): crystalline slurry for local repair, cementitious coatings for non-structural small works.
5. Quick Recommendation
For isolated footings with water table — use coal-tar epoxy high-solids coating over a moisture-insensitive epoxy primer; polymer-modified bitumen may be used where manufacturer & site conditions permit.
6. System Details & Application Steps
A — Pre-work & Surface preparation
- Make surfaces slightly rough using grinders with vacuum extraction (avoid dust).
- Remove oil, grease, wax, laitance, curing agents, loose plaster and foreign matter.
- Repair honeycombs and defects with appropriate repair mortar.
- Substrate moisture: surface should not be damp — target moisture < 5%. If moisture is above limit, advise remedial drying or alternative technology. 02_Isolated footings with water…
B — Primer
- Apply a moisture-insensitive epoxy primer over the external concrete surface up to finish floor level.
- Dry film thickness (DFT) of primer: ~100 µm (as per project/manufacturer). 02_Isolated footings with water…
C — Coal-Tar Epoxy High-Solids Coating (Primary Coat)
- Apply single coat of coal-tar epoxy based high-solids coating to achieve minimum DFT 200 µm (vertical surface) by brush/roller as per drawing.
- Cure coating for minimum 72 hours before handling / backfill. 02_Isolated footings with water…
D — Detailing (joints, edges, penetrations)
- Treat construction joints, cold joints and cracks prior to coating as per structural guidance. Consult structural team for cracks.
- At penetrations/pipes, provide proper collars / flashing detail as per drawing and seal with compatible materials.
E — Protection & Completion
- After inspection & cure, protect coated surface during backfilling (avoid sharp stones / direct impact).
- Record all repairs on as-built drawings.
5. Video Masterclass
Conix Masterclass: Isolated Footing Waterproofing — Coming Soon
Disclaimer
Conix is an industry initiative & a neutral resource, compiled from industry references and best practices. It is not brand-specific. Always cross-check with project requirements and local codes before finalizing specifications.
