Water Based Damp Course Protection Chemicals: Tech-Dry Building Protection Systems
Tech-Dry Building Protection Systems Pty Ltd has developed a range of water-based damp course chemicals for the building industry. These water-based formulations have replaced the solvent-based formulations previously used by Tech-Dry.
Tech-Dry Building Protection Systems Pty Ltd was formed in 1982, and specialises in the development and supply of materials for the prevention of rising damp to the building industry. In common with other companies in the building protection industry, Tech-Dry initially used solvent-based products. However, in conjunction with Victoria University they have developed a range of water-based compounds for the prevention of rising damp. Over the past five years the company has made significant investments in research and development, which has resulted in the development of a number of environmentally friendly products and processes for the building industry.
- the curing of rising damp via the installation of silicone damp courses;
- the manufacture and distribution of admixtures for the building industry; and
- the production and distribution of water-based damp coursing fluids (DCFs) to stop water ingress into mineral building materials.
Traditional methods of providing dampcourse protection to houses and buildings suffering from salt damp have involved the use of DCFs that consist of a reactive silicone compound in a hydrocarbon solvent carrier.
The DCF is applied to the surface requiring treatment, by saturation flooding at low pressure. These products typically contain five per cent silicone compounds and 95 per cent carrier solvent. The solvent acts solely as a carrier to deliver the active silicone compound into the interior of the substrate. After application the solvent evaporates into the environment and plays no further part in the process.
An average residential property requires in the range of 300 litres of DCF, therefore approximately 285 litres of solvent is emitted to the atmosphere via evaporation over a period of time.
Additionally, solvent-based products present problems due to flammability and odour. Dangerous goods handling and storage requirements must also be met when using solvent-based products.
Cleaner Production Initiative
Tech-Dry has developed a series of DCFs that do not contain hydrocarbon solvents. The products consist of special silicone compounds which are either emulsified with, or dissolved in water to form stable solutions. The products have a performance equal to the hydrocarbon solvent based products, but with the advantages that they do not release hydrocarbons on use, and are not flammable or corrosive. The three main products are:
- a general purpose silane/siloxane emulsion for the impregnation of a wide variety of substrates such as render, brick, terracotta, cement-stabilised earth and stone;
- a silane emulsion for the treatment of dense concrete; and
- a silicone solution for the remedial treatment of rising damp.
Application of DCF is achieved by a diffusion process whereby:
- tubes are placed into the wall 100 mm apart and are left for about 6 hours while the DCF diffuses into the wall structure;
- the usual volume is approximately 3 litres per metre of single brick wall and 6 litres per metre of double brick wall;
- the siloxane in the DCF polymerises and bonds to the masonry to form a permanent damp course which is effective at preventing the migration of moisture.
Research and development work is currently being undertaken to develop water protection products for wood, which will aid in the prevention of dry and wet rot of wood structures in the building industry.
Advantages of the Process
The formulation of the damp course protection materials has changed from 95 per cent solvent to 90 per cent water.
This has eliminated use of approximately 26,000 litres of solvent per year by Tech-Dry.
The advantages of this technology are:
- the products are virtually odourless;
- there are no hydrocarbon solvent emissions to the atmosphere;
- the products are non-flammable;
- the products are non-corrosive;
- all equipment can be cleaned in water; and
- the products are 10 to 15 per cent lower in cost.
It is estimated that in Australia, approximately 3,000-4,000 tonnes of hydrocarbon solvent are released to the atmosphere every year due to the installation of silicone damp courses and the surface impregnation of building structures.
Cleaner Production Incentive
Tech-Dry initiated the switch from solvent to water-based products because of their awareness that solvent-based formula impacts on the environment, including contributing to photochemical smog, occupational health and safety concerns and their awareness of trends in both the USA and Europe to place limits on solvent contents of various consumer products.
In addition, there was an increasing consumer demand for non-toxic and odourless products.
The main barrier to further adoption of the water-based technology in the building protection industry has been the lack of any specific environmental legislation aimed at moving away from traditional solvent-based products.