Rising dampness is the capillary rise of water within a wall's masonry pores. Brick, stone and mortar are all susceptible and the degree of dampness will vary depending on the size of the pores, wall thickness and the level of the water table. It is actually the hygroscopic salts carried to the wall surface which causes visible internal problems. These nitrate, chloride and sulphate salts absorb atmospheric moisture resulting in the breakdown of decorative finishes and plasters.
A thorough survey is always crucial to establish the source of dampness. Frequently, dampness is the result of condensation or poor maintenance. If, however the dampness cannot be controlled by lifestyle changes or building design adaptations we generally recommend two routes:
• A Dryzone cream damp proof course followed by re-plastering with Stonehouse Premix No. 5 plaster and Pro-proof R additive.
• A 3mm cavity drain membrane system which creates a physical barrier. This method is ideal for listed properties where the fabric of the building should not be compromised.
Often the most effective treatment of controlling rising dampness is through the correct installation of a damp-proof course. Stonehouse uses the Dryzone system which is a damp proofing cream introduced at intervals into pre-drilled holes in the mortar course. It is not injected under pressure and allows the solution to slowly diffuse into the wall fabric, line the masonry capillaries and reducing the level of moisture rise.
There are particular considerations when treating historic buildings for rising dampness. It is a priority to preserve the integrity of the building's fabric and finishes by sympathetic repairs. Secondly any procedure has to be reversible, making it always possible to return to the original construction. For this purpose, we recommend a flexible polypropylene membrane fixed at intervals with plugs. This provides a barrier between the old surface and the new finish while allowing the water within the wall to evaporate. It is then possible to apply plaster over the meshed membrane base following the contours of the wall or alternatively the walls can be dry-lined. This technology is suitable for plinths below the soleplates of timber frame buildings.
High external ground levels bearing against the walls of a property will result in laterally penetrating dampness. If it is not possible to reduce these high ground levels, a Stonehouse surveyor will consider and select one of the following internal solutions -
• We can utilise our own plaster mix to ‘tank’ the internal wall surface, specifically using Stonehouse Premix No.5 with a higher concentration of Stonehouse Pro-proof R additive. We link the walls and floor with a junction at this vulnerable position.
• Alternatively, we may suggest using a cementitious slurry system such as Vandex BB75 in conjunction with Stonehouse Premix No.5 in areas of high risk.
• If there is a well-ventilated timber floor, we often choose a cavity drain membrane system, extending the membrane down into the sub-floor void.
We offer long-term guarantees for all categories of works which are frequently in conjunction with the installation of a damp-proof course.
Condensation is the most common cause of dampness and resultant mould growth in buildings. In our hermetically sealed modern homes where ventilation and circulation are restricted, condensation can be an unpleasant frustration.
The symptoms of condensation are easily misdiagnosed for other issues of water ingress. It is a greater problem in winter months when properties old and new are heated. High levels of water vapour can build in kitchens and bathrooms with water vapour diffusing across rooms to condense on cold impervious surfaces. An associated mould will also form in areas where circulation is poor, behind furniture inside fitted cupboards and in corners.
Condensation occurs most visibly on cold wall and floor surfaces but also affects roof and subfloor spaces where timbers can become damp and decay.
Stonehouse surveyors inspect each project individually and employ a number of methods to control condensation. These solutions include mechanical fans and insulated vents to installing insulation with an integral vapour barrier. The following case studies show examples of our work.
There is now convincing science that we are in an era of global warming. Britain has recently suffered more than its usual share of prolonged, heavy rainfall. In recent years this has led to millions of pounds of damage to properties and misery for the businesses and homeowners affected by flooding. As our weather patterns shift, properties in flood affected areas are taking measures to cope with increased water tables and sudden deluges. Stonehouse uses its expertise in basement waterproofing to apply the same technology to properties prone to flooding.
We install flood mitigation systems to slow down water penetration with secondary pumping systems to remove the water that enters. These pumping systems have battery back-ups, in case of power cuts and are also available with self-start generators. They work on the same principle as a ship’s bilge pump which removes water faster than it enters the building. These systems, together with the use of flood guards at door openings can offer immediate response and protection to the fabric and interior of any property whether modern or listed.
Some of our most challenging projects are to design systems to flood-proof properties in areas of historic flooding and high risk. We invite you to watch the following video and hear the experiences of two of our clients.
We have a great love and respect for timber and all its various species and prefer to treat causes of infestation rather than the symptoms.
The impressive mushrooms of active Dry Rot, the bore holes of Death Watch Beetle and Woodworm are always an indication that timbers are in contact with moisture. Isolating the moisture source will control the outbreak.
We take into consideration the type of timber and its natural durability before recommending solutions. If a timber has been used in an inappropriate situation, we may have no option but to replace with a more durable type.
Occasionally targeted timber treatments or repairs are necessary when sections are structurally weakened or if the drying out process is protracted but this is only specified by Stonehouse as a last resort.
We are timber specialists who aim to conserve and whenever possible avoid chemicals.
Listed and traditional buildings require a sympathetic approach and an individual assessment of each property is essential. Specialist advice must be based on an in-depth understanding of traditional building techniques and materials, which few companies can offer.
The surveyors and operatives at Stonehouse Property Care are respected specialists in the field of protecting and preserving historic properties and actively promote a sustainable approach to conservation. At the forefront of environmental techniques, we keep intervention to a minimum and advise on maintenance programmes rather than intrusive repairs.
For instance, we would only advise a cavity drain membrane system for the control of dampness - this is fully reversible and does not exert any extra pressure on the structure. Timber treatments are also targeted and only recommended when fully justified.
We would be delighted to help protect your property and ensure its survival for future generations.
GREEN ROOFS AND WALLS
Green roof and wall technology has considerable benefits for property owners, the community and environment.
On an aesthetic level, a green roof or wall has the appeal of softening a building and blending into the surrounding environment. Green roofs and walls create alternative green spaces and natural habitats in urban settings, improving air quality and neutralising pollutants. They require little maintenance and are uplifting, living, natural works of art in the most uninspiring of locations.
Practically, the ‘build-up’ of a green roof will protect the structure below. Waterproofing is screened from heat fluctuations and UV light by green roofs. This can significantly extend the life of a roof and reduce air-conditioning and heating costs. In the event of torrential down-pours, water ‘run-off’ is controlled by the percolating effect of the green roof which in turn allows storm-water drainage to cope better.