Damp is caused by many factors and it is often cited that surveyors misdiagnose the causes of damp. Personally, I don’t think so, but I’m convinced it’s true that homeowners tend to ignore damp and mold, a bizarre and self-defeating stance, or become paranoid and seek to completely eliminate all traces of damp (which is not always a wise thing to do).
Nothing could be worse than ignoring problems because they usually get worse. Our second reaction is often to hire a specialist moisture testing contractor. While this may be correct and appropriate, in my experience these vendors often sell a solution that is not needed and costs you a small fortune. That solution usually means that chemicals will be injected into the walls of the house and in this green world this may not always be correct.
It’s all subject to scale and grade, but the smartest course of action is usually to have your local Chartered Surveyor inspect and advise. I can be accused of speculation here, but I reject being biased. Dampness can be caused by so many different factors that a true analysis is absolutely essential to ensure that the solution is sustainable. Where does moisture occur, why and is it necessary to complete a repair?
The best way to prevent moisture is to design a suitable barrier and install it effectively during building construction. If not, an upgraded system should be considered and such systems are often disruptive and expensive.
Another serious problem in the moisture diagnostics industry must also be considered: often the cause of the moisture problem is misdiagnosed and this can lead to a lot of unnecessary expense or worse, doubled costs over a period of years as a second solution. then it is tested.
Condensation is often the real problem and this may be associated with a lifestyle problem rather than a construction defect: in fact, in my experience, the vast majority of moisture that has been rectified by injection systems of chemicals (see below) are, in fact, a combination of inadequate insulation and a lifestyle problem that revolves around your own actions and methods of living in that particular building.
In addition to these problems, there is a danger that, historically, observed moisture may have brought minerals from the soil with it. These can migrate up and into the base wall plaster in rooms below. This contaminated plaster usually needs to be removed (but not always) and affected rooms are then re-plastered at great cost and disruption. Moisture may also have started the process of carpentry or flooring deterioration which may not manifest itself for many months, so it is usually worth exposing and lifting the floorboards before any work is specified; hence my assertion that it is generally worth hiring an experienced surveyor. to see the house before the works begin.
The moisture diagnostics industry is driven by free surveys conducted by the company competing for the reconditioning repair job. Conflicts of interest often result in misdiagnosis and all for the good of homebuyers or homeowners who save a few pounds by not seeking the paid opinion of a local, independent Chartered Surveyor.
So what are the main types of repair systems if a real rising damp problem has been correctly diagnosed? Here is a basic list —
chemicall Retrofit injection systems – These place chemicals within a wall in such a way that the microporous structure of the masonry cannot absorb moisture and this solidity prevents capillary attraction and therefore moisture cannot enter your home. Small holes are drilled in the bases of the walls (usually on the exterior, but in some cases an interior system can be designed) and then a chemical solution is systematically injected into the masonry until the saturation point is reached.
electro-osmosis: If a small electrical current (equivalent to that used by a doorbell) is passed through a wall, it affects the rate of potential capillary attraction that causes water to rise up a wall (like a tree sucking water from the ground). This system typically has a control unit (an adaptive power source), anodes drilled and set into the bases of the exterior walls, and finally a ground rod. These are provided externally and are effective if the circuits are not broken or the power supply interrupted.
Physical = the introduction of a new barrier, such as bituminous felt, plastic (polypropylene, EPDM or recycled), dense brick layer (engineering grade) and mortar, lead or natural slate. Any physical barriers shall be attached to any soil membrane and be at least 150mm above exterior soil levels. The precise position of the barrier must also ensure that the ends of the suspended and embedded floor joists are protected from moisture and the resulting deterioration.
Schrijver system: (a proprietary brand product used as an example to identify any such system, a specialized physical system) = this is based on special embedded devices placed inside a wall (inserted from the outside using a drilling process) that they create cold spots where water is directed. drawn. That moisture is then collected and safely drained away.
palliative measures – in essence these work on the principle that humidity is not the problem; instead, address and neutralize the effects of moisture rather than prevent the source(s) of moisture (as long as no serious consequences result from such proposals) — 1. Create a new inner skin with membrane against humidity and insulation but with a ventilated space between old and new interior walls. Possibly completing this work in conjunction with external land drainage work. 2. Changes in the lifestyle patterns of the occupants. 3. Provide better insulation and/or improve heating and ventilation of the building environment (or simply better control of such factors).
There are arguments for each type of repair theory, or action to combat humidity and its effects (mold, deterioration, health problems…). Factors in deciding the best solution for you may include:—
• The robustness of the correct diagnosis of humidity. The importance of this factor cannot be overstated, as surveyors initially misdiagnose the vast majority of moisture cases.
• If the degree of humidity justifies any action.
• How green you need your repair solution to be.
• The efficacy and longevity of the different types of solution.
• The costs, direct and indirect, of your preferred repair solution.
• Whether guarantees are issued and under what conditions (eg be backed by insurance?).
• Whether it is advisable to repair moisture at all, eg: adobe-walled buildings must be damp to remain structurally safe: eg, flint walls cannot be injected: eg, generally thin wall forms Vintage buildings need to breathe and this prevents most repair work methods.
• Peripherals, such as the degree of expertise required by the repair company, whether Construction Control Approval is needed, the time required to complete repairs, what conditions are placed on each method of repair, any adverse effects on the possibility of sale or mortgage of each type of repair. systems etc…
• Sometimes repair work may affect an adjoining structure and therefore the cooperation (sometimes required under the Partitioning Walls Act) of the adjoining property owner is needed before anything can be done.
It seems that the Industry has fallen into saying The solution is a chemical injection repair treatment, now what is the problem?? Until we can get a bit more sophisticated, we’ll continue to complete unnecessary work and/or use chemicals when we often shouldn’t.
The crux of the matter often revolves around two factors (1) whether the wall plaster needs to be removed and replaced, as this adds significantly to costs and contract length, plus (2) are you prepared to accept that the way you live inside the house has changed? caused the damp and mold and you may have to make lifestyle changes: (this last scenario is real and in my experience occupants often won’t believe the problem is self-inflicted. This works in the favor of the dishonest moisture specialist companies).
It really is quite simple – with each household and method of occupancy being so variable, there is no one-size-fits-all solution and therefore you need good quality advice. So will you take the advice of an unbiased certified surveyor or trust Bob the Builder or a salesperson for a moisture contractor company? The choice is yours.