Waterproofing Design Specialists looking at a plan

What’s the difference between basement tanking and basement waterproofing?

17 July 2018

For most people, a basement is just an old, musty storage space for your office where the Christmas tree, stationary or archived files live, however, there is a lot more potential to an unused basement than this. When our customers look to convert their basement into further commercial space they often ask the question “what is the difference between tanking and waterproofing?”.

Put simply, basement waterproofing typically refers the generic types of waterproofing available (Type A, Type B and Type C) whereas basement tanking describes the application of barrier protection, in the form of a slurry or membrane (barrier protection).

What is tanking?

Basement tanking uses a “barrier” to keep water out of the property. By applying an appropriate waterproofing barrier to the walls, the base slab and, where relevant, the roof of a below-ground structure, so that the entire envelope of the structure below ground is protected against water ingress.

Tanking waterproofing for a large commercial property in London

The client needed a waterproofing system designing and implementing in order to make the basement a dry, usable space again. The waterproofing team at Timberwise were called out to in order to lend their waterproofing expertise to the design of a suitable waterproofing system and ultimately to install the basement waterproofing system.

The application of the Sika waterproofing system was applied to the walls. A total of 3 layers alongside a skim coat of finish plaster was applied to leave the area dry and ready for further decoration.

Read full case study here

What is basement waterproofing?

Waterproofing describes materials and methods used to protect a structure from water ingress that might also provide resistance to the diffusion of water vapour. However, a cavity drain membrane is not considered to constitute a tanking system.

Type B: Structurally Integral Protection (usually to the relevant British Standard and of reinforced concrete structure) (BS 8007 and BS 8110)

The water tightness of the Type B construction is reliant upon the design and construction of the basement as an integral shell rather than modifying an already pre-built basement. Structures that provide Type B protection are usually made of reinforced water-resistant concrete or structural steel.

Type C: Drained Protection (cavity drain membranes and construction drained cavities)

As opposed to traditional tanking that works by holding back the water and pressure, the cavity drain membrane allows for water ingress to penetrate the structure. The water then trickles down the membrane fixed to the wall and collected at the bottom, the flow of the water is then controlled through the perimeter drainage channel and directed to a drainage point/sump pump.

Type C systems require regular maintenance as the drainage channel and sump pump can incur blockages which ultimately will result in the basement flooding.

Basement waterproofing with a Type C for homeowners in Lichfield

The property is a two-storey domestic house and the basement was constructed of traditional brick, with an arched ceiling below the front room of the property; there was no evidence of any previous waterproofing.

The desired outcome of the project was that the customer was left with dry storage space, so in accordance, the current British Standard, a cavity drainage system was recommended as the most reliable and robust waterproofing system for the job.

Read full case study here

What BS8102:2009 recommends…

BS 8102:2009 is the code of practice adhered to by Waterproofing Design Specialists for the protection of below ground structures against water from the ground. The code ensures that the basement waterproofing is carried out in the safest way possible and to the highest standards.

If you have any questions why not speak to the experts today?

Each waterproofing solution is completely personalised to meet the needs of the customer – there is no one size fits all solution. You can trust Timberwise to provide you with the right waterproofing solution for your commercial building.

Don’t hesitate to contact Timberwise by calling on 0800 288 8660 or you can request a survey. A survey through Timberwise will be able to identify the extent of the problem and determine the right waterproofing solution for you and your property.

Originally published 17th July 2018, updated 18th July 2019.