404 Cavity Membrane – Damp Proofing, Woodworm, Dry Rot, Barnstaple, North Devon
Cavity Membrane 2018-03-21T11:08:30+00:00

Cavity Membrane – General Information

It is recognised that there are various forms of cavity membrane systems. The preferred system of Anchor Property Care is Delta Membrane of which we are a registered installer. Delta had BBA accreditation.

With the introduction of the latest British Standard 8102 (1990) for the Protection of Structures Against Water from the Ground, the use of cavity membranes has been generally accepted throughout the UK. The membrane system is a complete range of products which can be used together to solve many of today’s problems in both new and old construction. The membrane system can easily deal with progressive ground water conditions where basements are liable to flooding, or indeed where simple dampness, contamination or salting problems are prevalent.

Other more diverse applications include turf-covered roofs, barn conversions, tunnel linings or even as a barrier against radon gas. The main components of the system are the membranes themselves. These are manufactures from virgin high-density polyethylene. The stud heights vary from 3mm increasing to an 8mm stud and a 20mm stud, which is primarily used on floor applications. The cavity created by the membrane contains between 2.1 and 10 litres of space respectively. This is known as either the ‘air gap’ or the ‘drained cavity’ in wet situations. Generally in our specifications, we would propose the use of 3 types of membrane, Delta MS500, Delta PT Lath and Delta MS20.


This is used for floor and wall applications. This membrane can be used for light water ingress situations.

PT Lath

This membrane has a mesh incorporated on the internal face, which is attached by the thermic welding process at the time of manufacture. The introduction of the mesh will allow a render of plaster finish to be applied directly to the surface of the membrane.


This is a heavy gauge version of system 500 with deep 20mm studs. This is used where extra drainage capacity is required. For example on deeper structures or where a larger flow rate is required.

Drainage Requirement

The following work to be carried out by the Client/Client’s Contractor, under a separate contract cost, unless otherwise specified within our report.

Where the system is being installed to cope with capillary held moisture can be done without the need for elaborate drainage facilities. However, when dealing with free water, or if there is a risk of water damage, then a suitable drainage facility must be incorporated within the system. This could be channels cut into the floor, soakaways, sumps, and mechanical pumps.


The following work to be carried out by the Client/Client’s own Contractor, under separate contract and cost, unless otherwise specified within our Report/Specification.

Depending upon the system installed, various options are available with regards to how the walls/floors can be finished. With wall applications the membrane, once installed, can be plastered or prepared in readiness for a dry lining system. Floor membranes, once installed, can be screeded or a ‘floating’ timber floor can be installed.

Drainage, Sumps and Pumps

Depending upon the installation and site conditions, the system will be reliant upon the free flow of water. Where gravity drainage system is being used, we strongly advise that the drains in the property are inspected by a drainage specialist prior to the installation of the membrane system. Any faults, blockages, etc., should be rectified. The condition of the drains is paramount to the effectiveness of the membrane system.

Where pumps have been recommended, it is important that the pumps are maintained and serviced on a regular basis. Pumps are installed by Anchor Property Care and a 12 month warranty on the pumps will be supplied. After this period of time, it is the Client’s responsibility to ensure that regular services and maintenance of the pumps in carried out. Maintenance Contracts are available upon request. Please see our ‘Pumps and Drainage’ technical sheet.