Damp-proofing is the process of creating a waterproof barrier that prevents moisture from entering a building. Common materials used for damp proofing include bitumen, polyethylene sheeting, and plastic membranes. Bitumen is applied to the surface of concrete and masonry walls to create a waterproof seal.
Materials. Materials widely used for damp proofing include: Flexible materials like butyl rubber, hot bitumen (asphalt), plastic sheets, bituminous felts, sheets of lead, copper, etc. Semi-rigid materials like mastic asphalt.
Plastic membrane is the most common type of DPM. These types of damp proof membranes are made from recycled materials, such as polyethylene or polypropylene, and comes in various colours, sizes, and thicknesses. Plastic sheeting is easy to handle and install, and can be cut, folded, or taped to fit any shape or size.
Condensation is perhaps the most common form of dampness that can appear in your property. It can cause wallpaper to peel, damp patches to appear on walls and a build up of moisture on your windows. This can lead to a growth in mould that appears as a cloud of little black dots.
Initially DPCs consisted of slate or lead barriers, fitted into the walls to protect against rising damp. More modern properties used bitumen felt and todays properties use a plastic DPC. A DPC may fail because it was not fitted properly or may fail due to deterioration, localised damage or bridging.
A damp proof course acts as a barrier that prevents rising damp from permeating up through porous walls from the ground. It is typically installed between courses of brick and blockwork approximately 150mm above ground and is commonly used in modern construction to combat rising damp.
Damp Proof Membranes (DPMs)
Newton Waterproofing offers two types of DPM: the physical Dampsafe 802-DPM sheet membrane, and the liquid-applied Epoxy DPM. Both of these membranes act as a barrier to damp, but are applied and used in different ways.
The most common treatment for issues with a damp-proof course is for a damp specialist to inject a damp-proofing cream into your wall to act as a new course. The cream is injected through drill holes in the masonry and once cured, it provides a protective layer to stop moisture rising through the brickwork.
Typically, a physical damp proof course lasts for 20-25 years and can fail due to it not being fitted properly or deterioration. If a damp proofing course has failed then this could potentially lead to rising damp. Rising damp is the movement of moisture through the walls and floors by capillary action.
Damp proofing prevents rising moisture from the soil. Waterproofing, on the other hand, stops any moisture and liquids from penetrating your structure. Additionally, waterproofing can withstand hydrostatic pressure, whereas damp proofing is not effective for water under pressure.
Chemical DPC fluids, such as Wykamol Microtech PIF Damp Proofing Fluid, work by penetrating the porous masonry when injected, filling the capillaries with a silicone micro-emulsion. This emulsion creates a continuous water-resistant layer that prevents moisture from rising through the walls via capillary action.
Metal sheets, such as copper or lead, can be used as DPC materials in areas requiring high strength and durability. These materials provide excellent resistance to moisture and are generally used in conjunction with other DPC materials for enhanced protection.
Common materials used for damp proofing include bitumen, polyethylene sheeting, and plastic membranes. Bitumen is applied to the surface of concrete and masonry walls to create a waterproof seal.
Silicone sealant is the best waterproofing material for your home. It is an adhesive liquid that looks like a gel and can maintain its flexibility and balance at both high and low temperatures. It is resistant to other chemicals, moisture, and weather thus minimising the chance of failing.
Class 3 waterproofing systems represent the highest level of moisture protection as per Australian Standard AS 4564.1. These systems are engineered to withstand continuous water exposure and are typically used in areas with the most severe water contact.
Damp-proofing sheets are impenetrable membranes typically made from high-density polyethene (HDPE) or polyvinyl chloride (PVC). These sheets are designed to prevent moisture from seeping into a building, acting as a physical barrier between the source of dampness and the structure's interior.
Some common materials used in the Damp Proof Course: Hot bitumen – This is a highly flexible material with a minimum thickness of 3 mm. It is applied to the bedding of concrete or mortar while it is hot.
This is the one of the common methods of damp proofing. All you require is a liquid wrap made from a polymer and apply it over the damp or moist areas. But before the liquid wrap is applied, use a waterproof joint filler to close any cracks and holes.
It is important to note that while a properly installed DPC can provide long-lasting protection against moisture penetration, it is not immune to wear and tear over time. Depending on the quality of installation and external factors, a damp proof course typically lasts between 20 to 30 years.
All homes built after 1875 should have a damp proof course – this is when it became a compulsory building regulation. You can find it by checking the outside of your house and locating a seal that runs horizontally across the brickwork. It usually sits about 6 inches up from ground level.
Chemical damp proof course injection
The benefits of a chemical damp proof course include speed, ease and cost, as compared to more intrusive damp proofing methods, a chemical damp proof course involves minimal time and work to install but is just as effective as other methods.