Waterproofing solution for a South Hams holiday cottage


Products Used: Cavity Drain Membrane, NB1 Waterproofing Slurry

Situated just a short walk from the sandy beach of North Sands with quick access to Salcombe town, and with uninterrupted views over the Salcombe Estuary, lies a luxurious and contemporary coastal holiday cottage.

Situated in South Hams an Area of Outstanding Natural Beauty, offering a peaceful location, unspoilt sea and country views, access to beautiful sailing grounds and sandy beaches it’s no wonder that the South Hams area is much sought after in the buy-to-let market. This particular detached cottage was constructed with no apparent consideration given to waterproofing the flat roof area or the earth retaining walls.

With this in mind, the client called upon Timberwise Torquay to identify what remedial waterproofing works would be required for the front store room. As local property care experts, Timberwise are no stranger to working with buy-to-let property owners in the area and helping to protect their coastal investments. As a result of our survey, we were able to confirm that the roof area was allowing water ingress and that a waterproofing solution would be required.

Did you know?

In 1764, the first holiday home, The Moult, was built in Salcombe by John Hawkins and is described as a “mere pleasure box”. By the end of the century, the house had been expanded and renovated several times by a succession of owners.

Waterproofing Design Methodology

Our waterproofing specialist recommended a combination waterproofing system. A combination system would offer the customer maximum protection against water ingress especially to the vaulted/intricate areas in the property. The methodology is that a liquid/cementitious (Type A) waterproofing system is used in conjunction with a Type C waterproofing system, this then provides extra protection and continuity of the waterproofing design.

The property’s roof was made from concrete paving slabs on the block and beam. Timberwise advised that the client was to lift those paving slabs and replace with a reinforced concrete slab before any external waterproofing could take place. Without a concrete slab Timberwise’s waterproofing solution could not be installed, due to a risk of movement which would lead to cracking and the system failing – a situation that neither the client or Timberwise would want to happen.

Once the slab was installed and before Timberwise’s arrival, the client removed all fixtures and stored items from the site. These preparatory works were essential to ensure there were no delays and that the waterproofing work could be carried out in the set-out timeline.

Externally, Timberwise specified and installed a Type A waterproofing system otherwise known as “barrier protection”. This compromises of a “barrier” applied to the structure, for this particular property Timberwise technicians applied two coats of NB1 cementitious waterproofing slurry to the top surface of the new reinforced concrete slab. This specific slurry allows for damage-free drying and de-salting of masonry even in the case of high salt contents, perfect for this coastal home which is exposed continuously to the elements of the seaside.

Cavity Drain Membrane

Internally, Using waterproofing plugs and waterproof tape 8mm cavity drain membrane was then installed to the walls in the storeroom. Cavity drain membrane is used for Type C waterproofing and delivers a grade 3 environment to BS8102:2009. In principle a cavity drain membrane system allows moisture or running water to travel behind the membrane within a controlled drainage system. Although it is imperative that the cavity drain membrane is not punctured or moved, it can accommodate minor movements within the structure.

The floor was tested to check for any sections of ponding before being covered in 20mm floor membrane and all joints to be waterproof taped and the floor membrane to be directly taped to the wall membrane to create a sealed system.

Perimeter Drainage Channel

The perimeter drainage channel is used to relieve hydrostatic water pressure and was installed at the base of the floor wall junction, the channel collects water at the bottom of the membrane and then via gravity disperses water around the perimeter of the structure and drains the water away to the external drainage point.


As the property was a holiday home and the clients’ permanent residence was elsewhere in the country, constant communication between the client and Timberwise via regular phone calls and emails was paramount to ensure the job ran smoothly. With the summer season fast approaching all works and preparations were completed on time and the property was successfully let to the first guests of the season.

Although no further works were required BS8102 requires that all drainage channels are maintainable. To achieve this Timberwise allowed for the installation of jetting eyes inspection points to allow access to the channel in the future. For complete peace of mind, Timberwise offered a 10-year guarantee in respect of all workmanship and 30-year manufacturer’s product guarantee on the membrane materials.

“It was great to help these home-owners improve the value and experience that their property offers, we understand that no two waterproofing projects are the same so we guide and lead to fit in with the customer’s requirements while achieving optimum results.

The finished house now provides the owners, and their guests, with a very comfortable and dry “home from home” whenever they visit

Tom Dear, Managing Surveyor CSRT CSSW ACABE

Contact Our Waterproofing Specialists in South Hams

You can trust our Timberwise team in the South Hams area to provide you with the right waterproofing solution to damp problems in your building. Don’t hesitate to contact Timberwise by calling on 0800 288 8660 or you can request a survey.

A waterproofing survey through Timberwise will be able to identify the extent of the problem and determine the right waterproofing solution for you and your property.