0016 NEGATIVE WATERPROOFING FOR DUMMIES · METHOD STATEMENT 0016 NEGATIVE WATERPROOFING FOR DUMMIES ... on the level of saturated soil surrounding the basement or retaining wall …

METHOD STATEMENT0016

NEGATIVE WATERPROOFING FOR DUMMIES

This document and the information here contained is provided as is and Envirotech makes no express or implied representations or warrantiesregarding this document. Envirotech shall not warrant that the document or information will be error free or shall meet any particular criteria ofperformance. The use of this document and its information shall be at your own risk and you assume full responsibility and risk of loss resultingfrom the use of this document and its information. Envirotech shall not be liable for any special, indirect, incidental, consequential, or punitivedamages in relation to this document and its information.

THIS DOCUMENT IS TO INSURE, AND CULTIVATE YOUR AWARENESS WHEN APPLYINGNEGATIVE SIDE WATERPROOFING SYSTEMS TO MASONRY BLOCK WALLS.

THE REAL IMPORTANCE OF WATERPROOFING CORRECTLY, REFLECTS ON THECONSEQUENCES OF “NOT” WATERPROOFING.

“Water damage is second only to fire as a cause of building decay and deterioration inAustralia.”

WHAT CAUSES HYDROSTATIC PRESSURE?

Water is one of the biggest nemeses when waterproofing below ground structures.Water ingress can cause a lot of damage when basements or retaining walls are not waterproofed or drained correctly.Damage to the external foundations and internal property can be greatly affected if either the waterproofing membranesystem is not the correct system, or the waterproofing membrane system has not installed correctly.Hydrostatic pressure is the force exerted by water and the total weight of the water, which causes the pull of gravity onthe water, so as the pressure increases the depth of the water increases. Hydrostatic pressure can also be caused bywater in the soil surrounding the foundation, as when it rains, water is absorbed by the soil that exerts pressureas a result of the volume of water that is absorbed by the soil.

In my opinion, all backfilling should be with clean soil and fully compacted to reduce settlement andwater absorption during heavy rains




Hydrostatic pressure can also be present in the soil i.e. ground water, so this will increase the amount of hydrostaticpressure against basement walls because of the presence of any water table and ground water.Most building situated near large bodies of water may suffer from a water table.Hydrostatic pressure can have a serious effect on your basement/retaining walls as Hydrostatic pressure can exert aforce of about 60 pounds per cubic foot. The total amount of pressure against the basement/retaining walls will dependon the level of saturated soil surrounding the basement or retaining wall as this can amount to thousands of pounds ofpressure of saturated soil.Any void or damage to a waterproofing membrane system will result in the basement or retaining walls allowing waterto penetrate like a bucket leaking water through a hole.Hydrostatic pressure is a part of nature, so waterproofing a basement or retaining walls correctly with the correctmembrane system with suitable drainage is imperative to eliminate water ingress.

NEGATIVE SIDE WATERPROOFING.

In most cases the obvious approach to rectifying water penetration through a basement/retaining wall is to excavateand replace/repair the waterproofing membrane. However, in some cases, the excess may limit the excavation of theexternal walls, so negative waterproofing was introduced with manufacturers developing negative side waterproofing.Manufacturers who produce negative-side waterproofing products will have to take into consideration water will alwayspenetrate through the structure under pressure, and with this water salts are carried which can damage the buildingstructure. In this case, all negative side waterproofing products need to become permanently adhered to the wall.Negative membranes should ideally be a mineral based product/slurry consistent to the substrate such as concrete,masonry or brick so the material becomes one with the substrate.The first coat must be of a slurry consistency to obtain some penetration into the substrate and to withstand negativewater pressure.Product must be free of chlorides and allow for vapour diffusion so water vapour can penetrate through the curedproduct.

Chlorides may attack steel reinforcement>




Conclusion

In many applications, negative waterproofing cannot be guaranteed by the contractor. There are risks of membranefailure due to salts pushing the membrane of the wall, may also allow chemicals into the structure that may deterioratethe steel and concrete, and may allow the water to be pushed to other areas of the building.The main reason negative waterproofing is carried out is the areas are fully accessible after installation, and if the areasstill allow water to penetrate through, they can be easily rectified without the excavation of soil or backfilling materials.Negative waterproofing can be an effective solution if the appropriate product is used and installed correctly, but therisks are much higher than installing the correct positive waterproofing.

Refer to 010 “HOW TO” on the Envirotech web site for negative sideinstallations.

Reference Contacts and Data:

Technical data, advice or technical assistance may be obtained by contacting Envirotech Waterproofing Solutions at: -

Web: www.envirotech-waterproofing.com.au/www.queenslandwaterproofingassociation.com/

E-mail: [email protected] Telephone: (07) 3865 3600Office Fax: (07) 3865 7600John Blasé Mobile: 0403684556

DO IT ONCE-DO IT RIGHT-FIXED FOR GOOD

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0016 NEGATIVE WATERPROOFING FOR DUMMIES · METHOD STATEMENT 0016 NEGATIVE WATERPROOFING FOR DUMMIES ... on the level of saturated soil surrounding the basement or retaining wall …