Damp proofing is often the most appropriate treatment for properties which have identified damp problems, such as rising damp or penetrating damp.
There are a number of ways that damp proofing can be carried out, which will include either of the following options or even a combination, if that is what is required to solve the damp problem.
At Rentokil, we are experienced in damp proofing walls, basements and cellars in properties of all ages and size.
The use of a low odour water-based silicone injection is generally regarded as the most effective type of damp proof course to prevent moisture rising through a wall and leading to rising damp.
Damp proofing fluid should not be confused with a damp proof membrane.
The term membrane usually suggests a physical barrier, whereas the principal of silicone injection is to line the pores of the wall structure to stop moisture vertically rising by capillary action. The silicone does not block the pores of the wall, it only lines them.
Following the insertion of a damp proof course it is common for re-plastering to be required. Any new plastering has to prevent damp and salts present within the wall migrating onto the internal wall finish.
The most common approach to re-plastering is using a dense sand and cement render as a backing coat incorporating a waterproof additive. Once dry, a gypsum skim coat is applied to give a smooth finish.
When the existing plaster is removed, there may be a lot of dust. We advise that adequate steps are taken to remove or cover furnishing for protection.
Following re-plastering a minimum of at least two weeks must elapse before the new plaster can be decorated and all areas need to be visibly dry.
At this time decoration should only be with a water based permeable emulsion, vinyl paints should not be used.
Permanent decorations such as wall papers can be applied when the wall is fully dry, which can take up to a year and in some cases much longer.
At Rentokil, we offer a structural waterproofing system which incorporates a single cavity drain membrane for the walls and floors, providing a solution to penetrating damp problems caused by high external ground levels.
In properties that have been flooded or are at risk of flooding a submerged sump pump would be installed below floor level to collect water penetrating through the walls and pump it outside to an external drain.
The damp proof membranes that are used have molded studs on the reverse side to give clearance between the membrane & wall /floor to allow water to drain away freely.
It is important that when the waterproofing system is designed for your property suitable ventilation is considered i.e. natural ventilation or an extractor fan or other appropriate ventilation equipment.
Without these measures being fully considered condensation is likely to occur.
The work is completed with the floor having tongue and groove flooring installed and the walls having plasterboard and skim applied. This solution will provide a dry internal wall surface, making the cellar or basement rooms of your property habitable again.
The above membranes can be used on properties where the walls are above ground but have been subject to major flooding. This allows the property to be re-occupied sooner than the normal drying periods allow.
We are also able to offer cementitious tanking as an alternative damp proofing solution.
The basis of the system is to coat the internal walls to prevent any dampness coming through this system therefore sealing moisture within the wall.
This is useful for dealing with general moisture in earth retained walls. However, where liquid water or flooding is a risk the better method would be to use a membrane system.
This system is applied in three separate cementitious coats and then re-plastering is applied for a final finish.
One effective solution is to lower the external ground level abutting the wall. This is often impractical and very costly and an alternative damp proofing measure will be required.
Call Rentokil Property Care on 0800 0121 437 for further advice on damp proofing, waterproofing & tanking or to arrange a damp survey.