A concrete or rendered pond needs waterproofing which also stops lime leaching out. Here at cotswold koi we have a broad range of pond paint and sealants from leading brands available to perform a variety of tasks.

Pond Paint not only waterproofs the sides of a pond, it is available in various colours. Bondaglass’ best selling G4 pond sealant/paint comes in clear, green or black for a natural look. Please note that two coats of the clear paint must be applied before using a coloured version.

G4 Pond Sealer
G4 Pond Sealer Clear
G4 Pond Sealer Clear G4 Pond Sealer is a moisture cured polyurethane which forms a non-porous seal on concrete rendered ponds, G4 pond sealer uses the moisture in the air and the render to harden, G4 pond sealer can be applied to slightly damp surfaces, but it is important that the render is sufficiently dry to be porous so as to enable the first coat of G4 pond sealer to bond and obtain a mechanical grip, G4 pond sealer can be applied in poor weather conditions, high humidity and at temperatures down to zero degree's. Koi Pond Construction Materials As a general rule the pond should be constructed to be structurally sound since the G4 pond sealer only provides the waterproof seal, on no account use a P.V.A based sealer to seal or prime any surfaces, these materials can contain ammonia and also stop the G4 pond sealer from adhering to the render. Ponds will normally be constructed with either brick, lightweight block or concrete block and then rendered, it is not necessary to add waterproofing agents to the render mix as this will increase the density of the render and can inhibit G4 pond sealer penetration, if a waterproofing agent has been used, simply rub down the surface with an abrasive to obtain a key. If a fibre is used to give strength to the render it is necessary to burn off or sand down any fibres that are on the surface, as any fibres that protrude will cause leakage, G4 pond sealer will not bond to the fibres. The cement render should be trowelled to an even surface but not to a smooth dense plaster like finish since this prevents the penetration of G4 pond sealer, new render should be kept damp for the first three days and then allowed to harden for 21-28 days depending on conditions. G4 Pond Sealer is an excellent sealer for brickwork, but below the waterline the brick should also be rendered. The reason is that while the G4 Pond Sealer is able to seal hairline cracks G4 Pond Sealer is not capable of bridging larger joints, cracks or holes. G4 Pond Sealer Method of Application Apply the first coat of G4 pond sealer by brush, a roller can be used but it is necessary to avoid puddling of the G4 pond sealer on the base, it is best to use a brush, allow the first coat of G4 pond sealer to become finger tacky ( like cellotape ) or dry enough to walk upon carefully, approximately 45-60 minutes depending on humidity, then apply 2nd coat of G4 pond sealer, when second coat of G4 pond sealer is finger tacky apply third coat of G4 pond sealer, no longer than 4 hours should pass between coats, if a colour is used, then use 2 coats of standard and 2 coats of colour, G4 pond sealer is mechanically hard after 24 hours but must be given 72 hours to chemically cure, after which the pond can be washed down with plenty of water, drained, and can then be filled. We strongly reccomend that you mix Black Knight Wizard Fibre or some similar fibre into the render mix. This will help prevent the frost cracking the render in winter and give additional strength to the structure. G4 Pond Sealer Clear Aplication Apply first coat of G4 pond sealer Clear by brush, a roller can be used but it is necessary to avoid puddling of the G4 pond sealer Clear on the base. Allow first coat to become finger tacky or dry enough to walk carefully upon, approximately 45-60 minutes depending on humidity, then apply the second coat of G4 pond sealer Clear. When second coat is finger tacky apply Third coat. No longer than 4 hours should elapse between coats. Normally 3 coats of G4 pond sealer Clear is sufficient to build a continuous surface film but on very porous substrates a 4th coat of G4 pond sealer Clear may be required, apply as instructed above. G4 Pond Sealer Colour Aplication The system is slightly different. When using G4 Pond Sealer Colour the first two coats must be G4 Pond Sealer Clear. This is because G4 Pond Sealer Clear provides the maximum non-porous seal and adhesion. Follow the application instructions as detailed for G4 Pond Sealer Clear but the last two coats will be G4 Pond Sealer Colour. G4 Pond Sealer is mechanically hard after 24 hours and workable on some 6 hours after final application. However, 72 hours must elapse for full chemical cure, before washing down the G4 Pond Sealer with copious amounts of clean water. This water should be drained off. The koi Pond can then be filled. Consumption of G4 Pond Sealer will vary slightly according to the porosity of the substrate. G4 pond sealer Clear - 3 coats = 550g per sqm for the three coats (approximatly 185ml per squ. metre) G4 pond sealer Coloured - 2 coats of Clear = 410g per sqm for 2 coats (approximatly 205ml per squ. metre) G4 Pond Sealer is available in Standard Clear, Black and Green. If rain is expected make provision for covering the coated area, since water can damage the G4 pond sealer during the curing process. As soon as it is superficially dry water should not affect G4 pond sealer
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G4 Black Pond Sealer
G4 Black Pond Sealer
G4 Black Pond Sealer G4 Black Pond Sealer is a moisture cured polyurethane which forms a non-porous seal on concrete rendered ponds, G4 pond sealer uses the moisture in the air and the render to harden, G4 pond sealer can be applied to slightly damp surfaces, but it is important that the render is sufficiently dry to be porous so as to enable the first coat of G4 pond sealer to bond and obtain a mechanical grip, G4 pond sealer can be applied in poor weather conditions, high humidity and at temperatures down to zero degree's. Koi Pond Construction Materials As a general rule the pond should be constructed to be structurally sound since the G4 pond sealer only provides the waterproof seal, on no account use a P.V.A based sealer to seal or prime any surfaces, these materials can contain ammonia and also stop the G4 pond sealer from adhering to the render. Ponds will normally be constructed with either brick, lightweight block or concrete block and then rendered, it is not necessary to add waterproofing agents to the render mix as this will increase the density of the render and can inhibit G4 pond sealer penetration, if a waterproofing agent has been used, simply rub down the surface with an abrasive to obtain a key. If a fibre is used to give strength to the render it is necessary to burn off or sand down any fibres that are on the surface, as any fibres that protrude will cause leakage, G4 pond sealer will not bond to the fibres. The cement render should be trowelled to an even surface but not to a smooth dense plaster like finish since this prevents the penetration of G4 pond sealer, new render should be kept damp for the first three days and then allowed to harden for 21-28 days depending on conditions. G4 Black Pond Sealer is an excellent sealer for brickwork, but below the waterline the brick should also be rendered. The reason is that while the G4 Pond Sealer is able to seal hairline cracks G4 Pond Sealer is not capable of bridging larger joints, cracks or holes. G4 Pond Sealer Method of Application Apply the first coat of G4 pond sealer by brush, a roller can be used but it is necessary to avoid puddling of the G4 pond sealer on the base, it is best to use a brush, allow the first coat of G4 pond sealer to become finger tacky ( like cellotape ) or dry enough to walk upon carefully, approximately 45-60 minutes depending on humidity, then apply 2nd coat of G4 pond sealer, when second coat of G4 pond sealer is finger tacky apply third coat of G4 pond sealer, no longer than 4 hours should pass between coats, if a colour is used, then use 2 coats of standard and 2 coats of colour, G4 pond sealer is mechanically hard after 24 hours but must be given 72 hours to chemically cure, after which the pond can be washed down with plenty of water, drained, and can then be filled. We strongly reccomend that you mix Black Knight Wizard Fibre or some similar fibre into the render mix. This will help prevent the frost cracking the render in winter and give additional strength to the structure. G4 Pond Sealer Clear Aplication Apply first coat of G4 pond sealer Clear by brush, a roller can be used but it is necessary to avoid puddling of the G4 pond sealer Clear on the base. Allow first coat to become finger tacky or dry enough to walk carefully upon, approximately 45-60 minutes depending on humidity, then apply the second coat of G4 pond sealer Clear. When second coat is finger tacky apply Third coat. No longer than 4 hours should elapse between coats. Normally 3 coats of G4 pond sealer Clear is sufficient to build a continuous surface film but on very porous substrates a 4th coat of G4 pond sealer Clear may be required, apply as instructed above. G4 Pond Sealer Colour Aplication The system is slightly different. When using G4 Pond Sealer Colour the first two coats must be G4 Pond Sealer Clear. This is because G4 Pond Sealer Clear provides the maximum non-porous seal and adhesion. Follow the application instructions as detailed for G4 Pond Sealer Clear but the last two coats will be G4 Pond Sealer Colour. G4 Pond Sealer is mechanically hard after 24 hours and workable on some 6 hours after final application. However, 72 hours must elapse for full chemical cure, before washing down the G4 Pond Sealer with copious amounts of clean water. This water should be drained off. The koi Pond can then be filled. Consumption of G4 Pond Sealer will vary slightly according to the porosity of the substrate. G4 pond sealer Clear - 3 coats = 550g per sqm for the three coats (approximatly 185ml per squ. metre) G4 pond sealer Coloured - 2 coats of Clear = 410g per sqm for 2 coats (approximatly 205ml per squ. metre) G4 Pond Sealer is available in Standard Clear, Black and Green. If rain is expected make provision for covering the coated area, since water can damage the G4 pond sealer during the curing process. As soon as it is superficially dry water should not affect G4 pond sealer
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G4 Green Pond Sealer
G4 Green Pond Sealer
G4 Green Pond Sealer G4 Green Pond Sealer is a moisture cured polyurethane which forms a non-porous seal on concrete rendered ponds, it uses the moisture in the air and the render to harden, G4 Green pond sealer can be applied to slightly damp surfaces, but it is important that the render is sufficiently dry to be porous so as to enable the first coat of G4 pond sealer to bond and obtain a mechanical grip, G4 pond sealer can be applied in poor weather conditions, high humidity and at temperatures down to zero degree's. Koi Pond Construction Materials As a general rule the pond should be constructed to be structurally sound since the G4 Green pond sealer only provides the waterproof seal, on no account use a P.V.A based sealer to seal or prime any surfaces, these materials can contain ammonia and also stop the G4 pond sealer from adhering to the render. Ponds will normally be constructed with either brick, lightweight block or concrete block and then rendered, it is not necessary to add waterproofing agents to the render mix as this will increase the density of the render and can inhibit G4 pond sealer penetration, if a waterproofing agent has been used, simply rub down the surface with an abrasive to obtain a key. If a fibre is used to give strength to the render it is necessary to burn off or sand down any fibres that are on the surface, as any fibres that protrude will cause leakage, G4 pond sealer will not bond to the fibres. The cement render should be trowelled to an even surface but not to a smooth dense plaster like finish since this prevents the penetration of G4 pond sealer, new render should be kept damp for the first three days and then allowed to harden for 21-28 days depending on conditions. G4 Pond Sealer is an excellent sealer for brickwork, but below the waterline the brick should also be rendered. The reason is that while the G4 Pond Sealer is able to seal hairline cracks G4 Pond Sealer is not capable of bridging larger joints, cracks or holes. G4 Pond Sealer Method of Application Apply the first coat of G4 pond sealer by brush, a roller can be used but it is necessary to avoid puddling of the G4 pond sealer on the base, it is best to use a brush, allow the first coat of G4 pond sealer to become finger tacky ( like cellotape ) or dry enough to walk upon carefully, approximately 45-60 minutes depending on humidity, then apply 2nd coat of G4 pond sealer, when second coat of G4 pond sealer is finger tacky apply third coat of G4 pond sealer, no longer than 4 hours should pass between coats, if a colour is used, then use 2 coats of standard and 2 coats of colour, G4 pond sealer is mechanically hard after 24 hours but must be given 72 hours to chemically cure, after which the pond can be washed down with plenty of water, drained, and can then be filled. We strongly reccomend that you mix Black Knight Wizard Fibre or some similar fibre into the render mix. This will help prevent the frost cracking the render in winter and give additional strength to the structure. G4 Pond Sealer Clear Aplication Apply first coat of G4 pond sealer Clear by brush, a roller can be used but it is necessary to avoid puddling of the G4 pond sealer Clear on the base. Allow first coat to become finger tacky or dry enough to walk carefully upon, approximately 45-60 minutes depending on humidity, then apply the second coat of G4 pond sealer Clear. When second coat is finger tacky apply Third coat. No longer than 4 hours should elapse between coats. Normally 3 coats of G4 pond sealer Clear is sufficient to build a continuous surface film but on very porous substrates a 4th coat of G4 pond sealer Clear may be required, apply as instructed above. G4 Pond Sealer Colour Aplication The system is slightly different. When using G4 Pond Sealer Colour the first two coats must be G4 Pond Sealer Clear. This is because G4 Pond Sealer Clear provides the maximum non-porous seal and adhesion. Follow the application instructions as detailed for G4 Pond Sealer Clear but the last two coats will be G4 Pond Sealer Colour. G4 Pond Sealer is mechanically hard after 24 hours and workable on some 6 hours after final application. However, 72 hours must elapse for full chemical cure, before washing down the G4 Pond Sealer with copious amounts of clean water. This water should be drained off. The koi Pond can then be filled. Consumption of G4 Pond Sealer will vary slightly according to the porosity of the substrate. G4 pond sealer Clear - 3 coats = 550g per sqm for the three coats (approximatly 185ml per squ. metre) G4 pond sealer Coloured - 2 coats of Clear = 410g per sqm for 2 coats (approximatly 205ml per squ. metre) G4 Pond Sealer is available in Standard Clear, Black and Green. If rain is expected make provision for covering the coated area, since water can damage the G4 pond sealer during the curing process. As soon as it is superficially dry water should not affect G4 pond sealer
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Impermax Aqua Liquid pond Liner
Impermax Aqua Liquid pond Liner
Impermax Aqua Impermax Aqua is an ideal liquid rubber pond liner suitable for a host of situations and surfaces that is simply painted on. The product is based on polyurethane (drinking water approved according to EEC directive 98/83/CE) and provides a smooth, seamless membrane. The finished membrane is constructed in various layers with the resulting liner being in excess of 1.4-1.9mm thick almost twice the thickness of conventional sheet liners and with the similar finish to fibreglass. As Impermax Aqua is a liquid pond liner, it is painted on and will be as durable as conventional pond liners once cured, being highly elastic and able to withstand expansion, contraction or slight movement in the support structure without compromise to its integrity. Impermax Aqua liquid pond liner is the new era of pond lining, its easy to apply with brush or roller gives a seamless finish, applied in 2 coats to achieve maximum strength and durability, available in a series of colours Impermax Aqua Liquid rubber is a new single component, high performance waterproofing material, based on Polyurethane, certified according to EEC Directive 98/83/CE, and which can be in direct contact with drinking water for human consumption. It can be easily applied on different kinds of surfaces used in hydraulic infrastructures such as concrete, mortar, ceramics, fibreglass reinforced polyester, etc. Curing time: 4-6 hours in the summer, 12-24 hours. Apply at least 3 to 4 layers to obtain a membrane thickness of 1,5 to 1,9 mm (2 kilo per m²). It is recommended to use Humidity Primer in most situations. Economic and easy to apply, it delivers a jointless continuous membrane which totally adapts to the surfaces to be protected. Extreme mechanical and chemical properties. Certified according to EEC Directive 98/83/CE, so it can be in direct contact with drinking water for human consumption. This membrane can easily be applied in spots which are difficult to access with other systems. It is easy to obtain uniform thicknesses combining the product with geomax and our thixotropy agent, even in extremely steep or even vertical areas Impermax Aqua can be applied even in cases of low temperatures and high relative humidities, obtaining very short cure times in combination with our PUR CAT additive. Product does not require any blends or special primers (it is a one component product). 2kg covers 1m2 For Vertical sides add thixotropy Impermax Aqua Application Guidelines Product must be applied in quantities ranging 1.5 up to 2 kg/m2, resulting in a membrane thickness of 1.4 to 1.9 mm. Ideally, it must be applied in 2 separate coats, best in different colours (assuring enough quantity is applied in each layer). It is important to mix the product well before its application with an electric mixer, at low rpm (avoiding that too much air enters the resin). It is also necessary to let the product rest for a few minutes so that air bubbles disappear. It is recommended to use Humidity Primer in most situations. Impermax can be applied even in cases of low temperatures (< 5ºC) and high relative humidities, obtaining very short cure times in combination with our PUR Cat additive.  
not rated £24.99£674.99 Select options
Black Knight Wizard Fibre
Black Knight Wizard Fibre
Black Knight Wizard Fibre The easy to use cement additive that makes your pond smoother, stronger and crack-resistant. Building a concrete pond has never been so easy. Black Knight Wizard Fibre has been in use for decades in specialised architectural and construction projects where very high performance is required to withstand sustained stresses or harsh conditions and where long service is important. Wizard Fibre is a very fine glass fibre designed specifically for mortar or concrete reinforcement. It has been in use for decades in specialised architectural and construction projects where very high performance is required to withstand sustained stresses or harsh conditions and where long service is important. Why use Black Knight Wizard Fibre ? Allows a much stronger mix, leading to a smoother crack-resistant finish that is safer for the fish:
  • Saves money
  • Increases workability, making it easier to apply
  • Far stronger, more durable and easier to use than polypropylene alternatives
  • Dramatically reduces the likelihood of leaks developing
  • High zirconia content offers superb alkali resistance
  • Wizard Fibre and Concrete Ponds
The addition of Wizard Fibre has several long-lasting benefits, with the bonus that it is very easy to use. The fibre matrix and the fact that there is a high cement content means that the mix is very sticky but creamy in texture. It flows and adheres to the wall much more easily than a traditional mix. This brings the practice of concrete pond-building within the scope of the average hobbyist, thus saving a considerable amount of money. When the final Wizard render has set and dried it can be painted with a proprietary pond paint. The special characteristics of Wizard ensure that it disperses evenly in the mixer. The product appears to be in flat strips but when water is added and it is subjected to the action of the mixer, all of these strips break into much finer strands. As these are so fine they do not present any kind of hazard if some of them are protruding from the final finish and therefore they do not require any further attention. A well constructed pond with a Wizard Fibre render and a good quality pond paint could last a lifetime. Mix proportions: 1 - 2% fibres added to the total mix by weight. 3 parts of building sand to 1 part cement. We recommend the use of a mortar plasticiser in the mix (available at builders' merchants) because it makes application easier. Coverage A 1kg pack of Wizard Fibre can cover 8 - 18sqm at 5mm thick. Typical mix proportions: 5 litres cement, 15 litres sand, 225 - 450g fibres. Notes: The addition of fibre to the mix will improve workability up to about 90g per litre of cement and will decrease above this figure. Maximum crack resistance and strength is achieved at about this level. We suggest you experiment on a test area before you begin the job. Allow extra time in the mixer for fibre dispersal. We suggest a minimum of 80 drum revolutions. Do not attempt to render in hot, direct sunshine. The mix will dry out rather than cure, and it will spoil. Do not apply in frosty conditions. This product should be applied only to surfaces that are sound and stable.
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