Planter Box Waterproofing in Sydney

What balcony waterproofing in Sydney actually involves

Balconies get wet and dry out. A planter box does not — the soil holds moisture against the membrane continuously, and roots grow toward exactly the junctions the membrane relies on. That combination means a box can be the source of a balcony leak while the balcony floor itself is sound.

How a planter box is made watertight

The work is the same in principle and fussier in practice: empty the box, dress the membrane up the inside faces and over the lip so water cannot get behind it, put drainage gravel and a working weep outlet in the base so the soil is not sitting in a bath. A box with no functioning outlet is a planter that has been converted into a pond. The lip is the detail most often missed. If the membrane stops short of the top edge, water wicking up through the soil simply travels over the rim and down the outside face, which is a leak the box will be blamed for and the membrane will have permitted.

Integrated planter boxes are a feature of the newer apartment stock this site covers, where they are built into the balcony slab edge rather than stood on it as pots. In suburbs where flats make up the overwhelming majority of dwellings — Macquarie Park at 89.5 per cent, North Sydney at 84.4 — that detail is common rather than unusual. Source: Australian Bureau of Statistics, 2021 Census, occupied private dwellings by structure.

Planter Box Waterproofing in Sydney — common questions

Does the planter have to be emptied?

Yes. The membrane goes on the inside faces of the box, which cannot be reached or bonded through soil.

Can a planter box cause a leak somewhere else?

Regularly. Water escaping a box travels through the slab and appears elsewhere, which is why a balcony leak is sometimes traced back to planting rather than to the floor.

What stops it happening again?

A membrane dressed over the lip so water cannot get behind it, and a weep outlet that actually drains. Most repeat failures are one of those two.