Structural Waterproofing

What types of Structural Waterproofing should I use to create a Waterproof Basement?

There are many ways to waterproof a basement and similarly, there are many different ways to construct a basement too. The construction methods will in some ways determine the types of waterproofing to be used and may also contribute as part of the overall structural waterproofing strategy. For example, contiguous piled walls can act as a physical structural barrier against water ingress.

 

Are there different options available for the Structural Waterproofing of my Project?

The question is often raised as to which type of waterproofing should be selected as being the most suitable for the project in question. There are a number of factors to influence the type of protection used, if it is a retrofit basement then protection from the inside is likely to be the only option available.

Types of structural waterproofing

If the basement is to be constructed in an open hole with plenty of room around it, then there are more options available to the designer. The British Standard for waterproofing BS8102:2009 sets out three main types of waterproofing protection, type A, B and C.

 

Types of Structural Waterproofing Material – What is the difference?

Type A waterproofing protection is described as a barrier and is applied either externally, bonded internally or sandwiched between two structural elements. Type A barriers are often pre-applied which means they are applied prior to the placement of concrete. Type A barriers can also be bonded membranes, liquid applied coatings or cementitious slurry coatings. Type A membranes need to be easy to apply and robust as the ground is often reinstated directly against them.

Types of structural waterproofing

This is why a commonly used material for Type A waterproofing is a Geosynthetic clay liner called Maxiprufe 2000 which is made from two layers of geotextile which encapsulate a layer of Bentonite clay. This self-healing membrane will stop any groundwater from tracking between the membrane and the structure. It will also bond to fresh concrete when it is applied prior to the concrete placement. This means there is a permanent mechanical bond between the membrane and the concrete which is essential in situations where clay heave is an issue.

This is why a commonly used material for Type A waterproofing is a Geosynthetic clay liner called Maxiprufe 2000 which is made from two layers of geotextile which encapsulate a layer of Bentonite clay. This self-healing membrane will stop any groundwater from tracking between the membrane and the structure. It will also bond to fresh concrete when it is applied prior to the concrete placement. This means there is a permanent mechanical bond between the membrane and the concrete which is essential in situations where clay heave is an issue.

Type B waterproofing protection is achieved either by the design of the structure or by the materials used in the construction of the structure itself. Type B protection can be achieved by constructing the structure using Hydrocrete Concrete which is a Hydrophobic pore blocking concrete admixture, this will provide a water resistant concrete. It is important to remember that any joints will always be the weakest points and therefore the most susceptible to allowing water ingress.

Types of structural waterproofing

It is for this reason that waterbars are so critical and should be installed in every joint both horizontal and vertical. Using Cemflex VB metal plate waterbars and inserting them into the freshly placed concrete will provide excellent protection against water ingress. Hydrophillic waterbars which swell when in contact with water should be used when it isn’t possible to use metal plate waterbars.

Type C waterproofing protection is sometimes referred to as a water management system and is always a form of protection applied to internal of the structure.

Types of structural waterproofing

Typically, type C protection is achieved by using Hydroflow HP membrane which is a cuspated membrane which forms a cavity between the wall the and membrane, enabling any water ingress to find its way to a sump pump and be transferred to a drain. The Hydroflow system includes hydrochannel and sump pumps which are used specifically for the transport of water out of the basement usually to the drains.

 

Which Type of Structural Waterproofing is right for my project?

Types of structural waterproofing

Selecting the correct type of protection and being sure you have made the right choice can be a difficult process. The British Standard makes some strong recommendations and gives excellent guidance, although not completely explicit There is also the question relating to the use of two types of protection. When is it necessary to use two types of waterproofing protection, and is it really necessary? The are a lot of good reasons for installing two forms of waterproofing protection but two of the main reasons are to meet the requirements of the buildings guarantee company and to allow for or preempt any installation defects. To produce a grade three living accommodation basement in a high-risk area, it is essential that two forms of structural waterproofing are designed and installed.

The British Standard defines the level of risk by the level of the water table and aligns the risk factor against the suitability of each type of protection citing that Type C protection is suitable for basements in all situations whether it be a high-risk situation or a low risk. Type A and Type B systems are also suitable for all low-risk situations and only suitable for high and variable situations under certain conditions and regulations.

If the basement project is a retrofit of an existing structure then usually protection can only be applied on the inside of the structure. This doesn’t mean, however, that you cannot apply two forms of waterproofing protection.

If the property is to be warrantied by a property guarantee company such as NHBC, LABC or Premier then it will be necessary for you as lead designer to enlist the services of a CSSW qualified waterproofing specialist who will take the information gathered to date and produce a compliant waterproofing design for you, selecting the right types of protection during the process.

 

Contact us about our comprehensive technical waterproofing design service

If you require the services of a CSSW qualified waterproofing designer or gas protection designer, or just simply need some answers to help with your design, visit us at www.fisproducts.co.uk, give our technical designers a call today on 02380 276166 or email us at projects@fisproducts.co.uk

  • Types of structural waterproofing
  • Types of structural waterproofing
  • Types of structural waterproofing
  • Types of structural waterproofing
  • Types of structural waterproofing
  • Types of structural waterproofing