PondLinersco Black Pond Sealer

PondLinersco Black Pond Sealer: Black Topcoat for Concrete and Rendered Ponds

If you have built a block or rendered concrete pond and want a deep black finish rather than bare grey render, this is the topcoat for the job. PondLinersco Black Pond Sealer is a single-pack, moisture-curing polyurethane that goes on over our Clear Pond Sealer to give the inside of the pond a uniform black surface. A black interior makes the water look deeper and shows off fish and planting. It is sold in 1kg, 2.5kg and 5kg tins, so you can buy close to the quantity your pond actually needs.

How much sealer do I need? Use the free pond sealer calculator →

Why it works

Clear underneath, black on top

The black coat is a finishing layer, not a standalone sealer. The first two coats must be the clear sealer, because the clear grade gives the strongest non-porous seal and grip on the render. The black coats then bond to the clear and give the colour.

Moisture curing, so British weather is less of a problem

The polyurethane cures by drawing moisture from the air, so it can be applied down to 0°C. Useful on a pond build, where dry spells are rarely long.

One continuous session

Each coat is recoated after 60 to 90 minutes and never left more than 4 hours. Because that window also applies between the last clear coat and the first black coat, the four coats are applied as one working session.

• Seals render so water stays in and lime stays out of the pond
• Uniform black finish over the clear base coats
• Applies down to 0°C
• Three tin sizes to limit waste

Where it's used

Typical jobs are new block-built and rendered koi or fish ponds, formal raised ponds with rendered walls, and older concrete ponds being repaired and refinished. It is also used to coat concrete flagstones, waterfalls, statues and other concrete pieces that sit in or around the water. It is not for flexible liners of any kind: for liner ponds see our pond liners instead.

Specifications

Choosing the right size

Work out the inside area of the pond: the floor plus every wall. For a 3m × 2m pond 1m deep that is 6m² of floor plus 10m² of walls, so 16m². Multiply by 0.4kg for the black coats (16 × 0.4 = 6.4kg) and by 0.41kg for the clear base coats (about 6.6kg). For the black, a 5kg tin plus a 2.5kg tin covers it with a little spare.

As a guide, a 1kg tin covers about 2.5m², a 2.5kg tin about 6.25m² and a 5kg tin about 12.5m² with two black coats. Buy the clear sealer at the same time, because it goes on first. The pond sealer calculator does the sums for you.

Installation, use & care

Repair cracks and clean the render of dust, algae and loose material. Apply two coats of clear sealer by brush, then two coats of black, recoating every 60 to 90 minutes and never leaving more than 4 hours between coats. Avoid thick coats. Let the final coat cure fully, then fill, leave 24 hours, empty and refill before adding fish. The product is flammable and an irritant: wear gloves and eye protection, keep it away from ignition sources and work with good ventilation.

Frequently asked questions

Can I use the black sealer on its own?

No. The first two coats must be the clear sealer, which provides the seal and adhesion. The black is applied as two further coats on top.

How much does a 1kg tin cover?

About 2.5m² with two black coats, at roughly 400g per m². You will also need about 410g per m² of clear sealer for the two base coats.

Can I use it on a pond liner?

No. It is not compatible with PVC, butyl rubber or bitumen, so never apply it to a liner or liner joins.

Can I apply it in cold weather?

Yes. It cures with moisture from the air and can be applied down to 0°C. Keep to the 60 to 90 minute recoat time and the 4-hour limit.

Ordering & delivery

Choose your tin size above and add the clear sealer to the same order. Orders are dispatched within 1 to 2 working days and usually take 2 to 4 days in transit; full details are on our delivery page. Sold by PondLinersco.co.uk (Express Matting Services Ltd, Burnley, Lancashire).