How to Waterproof Your Property

Damp, water and rain can cause damage to your home, especially on the external parts of your property.

Here is a guide on the types of sealants that you can use to help prevent water absorption and retention and protect your home against damp, water penetration and leaks.

Water Seal

A water seal is a penetrative water proof substance that is clear and colourless. It is a water repellent liquid that contains silicones used for preventing the entering of water through porous surfaces. For instance, bricks over a period of time will lose their resistance to water penetration. A water seal will replace this resistance. Water sealant is ideal for porous surfaces and building materials such as brick, stone, cement rendering and concrete.

A water seal also has the added benefit of letting a wall breathe, allowing moisture into walls to evaporate. It will also help to keep walls dry and clean and help prevent efflorescence, frost damage and general erosion by water.

A water seal should be applied when the weather has been dry for at least 3-4 days and there is no rain or frost due on the day of application. It is easy to apply with a soft brush, working from the bottom of the wall upwards. On tough our very porous surfaces, two coats should be applied, the second applied when the first coat is fully dried. Another coat can be added after 30 days.

Liquid Damp Proof Membrane

A liquid damp proof membrane is a rubberised bitumen based emulsion that forms a flexible waterproof membrane on solid walls and floors when it is dry. The membrane is sandwiched between a concrete floor structure and the overlaying screed and provides a very resilient barrier to damp through floors and walls. It can also be used with brickwork or before plastering a wall.

A liquid damp proof membrane should not be used on floors or walls where water is present under pressure, for instance in retaining walls, wet rooms and cellars.

The membrane should be applied with a broom or brush to a floor and given two coats. For internal walls, three coats of membrane should be applied prior to plastering. The membrane should not be applied if the temperature will drop below 4 degrees celcius or if it is raining. Protective clothing and goggles should also be used when applying this damp proofing.

Protective Bituminous Paint

This black bitumen based paint is used for metal and concrete and provides a protective coating for iron, steel, metal, castings and concrete. This type of coating has a high resistance to water penetration, oxidation and weathering. Application can be made by brush or spray after thinning with white spirit. Protective clothing and goggles should be used when applying. The paint can be reapplied as and when it weathers and requires another coat.

Interior Damp Sealing

For damp on interior walls, a water based coating can be used to prevent stains from damp patches showing through subsequent painting. It seals the staining caused by previously damp areas on interior ceilings and walls. It can easily be applied by a paint roller or brush.

Waterproofing for Roofs

There are many waterproofing substances for roofs that can be used. A bitumen based solution can be used on asphalt, concrete, slate, corrugated iron and lead or zinc sheeting to create an effective barrier to water penetration.

Two coats should be applied by brush or over large areas by a broom. Gloves should be used when applying.

Acrylic Waterproofing

Acrylic waterproofing is an acrylic resin based waterproof coating for roofs and gutters that is durable and tough. This can be applied in wet weather and provides an instant solution to leaks. This type of waterproofing is ideal for immediate and isolated repairs or as a complete coating on a roof. It can be applied by brush and used in split and cracked areas that are prone to leaks.

Flexible Sealant for Roofs

This sealant is a bitumen based mastic sealant for filling and sealing cracks and joints in gutting and roofs to prevent leaks. It can be applied with a knife or trowel and should be waterproofed when dry with a general purpose roof water proofer.