Planter box waterproofing rectification

Why planter boxes leak

A planter is a small tank that is never allowed to dry out. The membrane inside it is exposed to constant moisture, fertiliser salts, root pressure and the movement of the structure around it, and the drainage outlet at its base is easily blocked by soil fines and roots. When the membrane or the outlet fails, water sits against the structure and migrates into the slab, wall or room below.

Planters are also frequently built against external walls or over habitable rooms, so the first sign of failure is often damp or staining inside the building rather than anything visible in the garden bed itself.

How the planter is investigated and scoped

Investigation involves locating every planter that drains onto or sits over the affected area, checking outlets and overflows, and in most cases removing a section of soil to inspect the membrane, protection layer, drainage cell and upstand height. DYME coordinates this with the consultant and, where structural cracking is suspected, with the engineer.

The scope sets out whether the planter is to be rewaterproofed, reconstructed with revised falls and outlets, or decommissioned and infilled, and whether adjacent slabs or walls need repair. Reinstatement of soil, irrigation and planting is defined so that the finished result matches what the owners expect.

How rectification is delivered

Works begin with removal of planting and soil and protection of the surrounding finishes, followed by substrate repair, new membrane with appropriate root-resistant protection, drainage layers and outlets, and testing by flooding the planter before anything goes back in. Soil, irrigation and plants are reinstated last.

Because planters are usually in common areas or on private balconies, staging and notices are coordinated with building management and residents. For a Sydney or NSW planter box enquiry, provide the building location, where the planters are and what is beneath them, any reports, photographs, access considerations, budget range and required timeframe.

Common questions

Can the planter simply be removed instead of rewaterproofed?

Decommissioning is a legitimate option and is included in the scope assessment. It still requires the underlying structure to be made good and waterproofed, and the owners need to decide whether the planting is worth retaining.

Is the planter tested before the soil goes back in?

Yes. A flood test of the completed membrane and drainage is held as an inspection point so the consultant can verify the repair before it is covered.

What happens to the existing plants?

Where they are worth retaining they can be lifted and held during the works; otherwise replacement planting is included in the reinstatement scope agreed with the owners.