Independent investigations into your home's damp problems with impartial advice on dealing with them
When you have concerns about damp in your home or a house you are buying, you need to discuss these with an independent Surveyor and Damp Consultant. An independent consultant can offer general advice and help you decide if you need a proper investigation of the damp issues. A proper investigation will result in a detailed report that will give you the specific advice and information you need to address the damp, as well as helping you avoid unnecessary and inappropriate building work.
There are many different causes of damp and it is common to find that a specific damp issue is the result of multiple problems. There are therefore many solutions to damp and a combination of these is often needed to deal with a single problem. Houses can also vary dramatically in their structural design and the materials they were built with, as well as being altered over the years. This means the solution for any given cause of dampness needs to be tailored to your individual home in order to be effective. Only by confirming the type of construction and getting to the root of the problem, is it possible to work out the best course of action.
To discuss your damp concerns, ring me on 01263 734815 or fill in the enquiry form at the bottom of the page.
To give you an idea of the range of problems, the following is a small selection of some of the more common causes of damp:
- Render made with Portland Cement which has subsequently cracked and started to separate from the backing wall. The defective area of render can be some distance away from where the damp appears. In the picture below, the wall with the large damp patch was a rendered brick solid wall. Immediately above the ceiling in the picture, the construction changed to a 1790s timber frame which had a rebuilt rendered brick cladding. As was common with timber frames of that period, there were no infill panels, just hollow voids hidden behind plaster and lath. The damp patches were caused by water getting behind the render much higher up. The cement mortar used for the rebuilt cladding had funnelled the water and directed it through to the timber frame, where it had been able to enter the hidden voids. The water had then run down inside the voids until it hit the brick wall at ceiling level in the picture. It had then pooled and soaked into the top of the brickwork, saturating the wall and appearing as shown.
Severe damp below an area of cracked Portland Cement render
- High flower and shrub beds against the walls of the house. This is frequently misdiagnosed as a damp proof course failure. The damp in the picture below was caused by a very modest and pretty rockery that had been built against the house a few years before the damp appeared.
Severe damp in a wall backing onto a small rockery
- Too much or too little ventilation. This is often accompanied by insufficient heating or the wrong pattern of heating for the type of house. In the picture below, the wallpaper has come away from the bottom half of the wall and black mould has taken hold. This was caused by of a combination of over ventilation and under heating.
Mouldy wallpaper coming away from a cold wall surface
- Exterior walls of the house painted with ordinary masonry or gloss paint, that goes down to the ground or in which tiny imperfections have formed. This situation can make certain types of wall extremely damp. In the first picture below, masonry paint on the outside of the wall has been taken down to the ground. This has caused salts to crystallise on the plaster as moisture evaporates from the wall into the house. The damp area in the second picture is one of several patches at varying heights, caused by a thick build-up of ageing masonry paint on the outside of the wall.
Salts from damp caused by external masonry paint going down to ground
Damp patch half-way up the wall caused by external masonry paint
- Leaking pipes hidden under floors or buried inside walls. These can go undetected for years, especially if hidden behind ceramic tiles. The first picture below shows a damp pattern which is often misdiagnosed as rising damp, but was actually on the first floor. It was caused by a leaking radiator pipe inside a wall some distance away – the water had run between the floor tiles and concrete floor then spread up all of the adjacent walls. The second picture shows damp from a central heating pipe buried in the concrete next to the wall.
Damp at bottom of walls from a radiator pipe within a wall some distance away
Well defined damp patch from a leaking underfloor pipe next to the wall
- Salt contamination of wall plaster by soot, tar and flue gases. These salts absorb moisture from the air to cause surface damp and staining, and come from chimney flues that are either unlined or where the lining has decayed. In the picture below, the large stain on the chimney breast has also spread round the sides. Cases like this are commonly misdiagnosed as leaks around the chimney. (The marks that look like damp where the fireplace used to be, are where the paint has been touched up.)
Large stain to upper part of bedroom chimney breast
The investigation of your damp problem typically starts with an initial inspection of the outside of the building to identify areas likely to be vulnerable to damp. Checks are also made for visible defects that could cause current or future damp problems. This is followed by an internal check for any visible dampness. The results of these external and internal checks determine where the more detailed investigations need to be carried out.
For the detailed investigation:
- an electronic thermo-hygrometer is used to measure the internal and external air temperatures and relative humidities. These measurements enable the internal and external dew points to be calculated and compared. This comparison helps to ascertain the adequacy of the background ventilation;
- the thermo-hygrometer readings are entered into a thermal imaging camera which is then used to measure surface temperatures and temperature variations across those surfaces. This will reveal where surface condensation is likely, where mould growth can occur independently of condensation, any localised insulation deficiencies, and the adequacy of the heating. Under the correct conditions, it can also reveal hidden construction details;
- walls requiring further investigation are checked with a selection of complementary types of electronic moisture meter: an electrical resistance pin probe meter can give accurate absolute moisture readings for any timber in permanent contact with the wall; a capacitance moisture meter can give relative readings of sub-surface moisture and salts to a depth of about 40mm (1½”); while a microwave moisture meter can give relative moisture readings to a depth of 300mm (12”). The multiple readings are plotted on a grid depicting the wall to create a moisture profile;
- sometimes the above measurements need supplementing with the lifting of floorboards or opening up of some part of the building to obtain further information;
- subsequent analysis of the moisture profile will reveal where excess moisture or salts are present, the height and depth of any moisture within the wall, its severity and variations in intensity;
- only by combining the results of the moisture profile analysis with the findings of the other checks and investigations carried out, can proper conclusions be drawn as to the nature, causes and severity of any damp problems.
The investigation is all very well, but it is no good unless you also receive a proper report. To be useful, the report needs to explain what the investigation uncovered, and provide appropriate recommendations and information on dealing with any problems found. To see the sorts of things covered, you can view a sample damp report here.
How much does a damp investigation cost? Prices start at £400 for any damp investigation, which covers the first 4 hours. Any additional time needed for the investigation, is charged at the rate of £75 per hour. Most investigations take 4 hours so the minimum charge covers most inspections. For all investigations, the only other cost is my travel expenses, which of necessity vary by location. Travel expenses include a contribution towards my time, and are calculated on mileage for the round trip as estimated by the RAC. As an indication, travel expenses are around £20 for Norwich, rising to around £200 for locations such as Derby, Coventry and Watford. There are no other charges – I am not registered for VAT, and don't charge for postage, or reports, etc.
Misguided attempts to cure your problems without the proper investigations can easily result in unnecessary expense through inappropriate building works, which often make the problem worse in the longer term.
Damp investigations are routinely carried out throughout East Anglia, the East Midlands, and the north-east fringes of London.
For damp surveys in other areas, the travel expenses can be disproportionate unless your home is larger or more complex. Some people therefore get together with a neighbour/friend living nearby to book a joint survey – this can be very cost effective as only a single set of travel expenses are incurred, and only one minimum charge for the joint booking (in these situations, two separate survey reports are still issued).
To discuss your home's damp problems or request a damp investigation, ring me on 01263 734815 or fill in the following form:
Privacy Statement - Your name and contact details will be held in the strictest of confidence. I will not under any circumstances share this information with any third party, unless I am compelled by a court order.
About David M. Kinsey
I am an independent Surveyor specialising in damp and its associated problems, particularly with regard to older houses. Based in Norfolk, I am regularly called upon to carry out investigations for clients throughout the East of England, Midlands, and the South-East.
My building surveying career dates back to the late 1970s. I have also been a Chartered Information Systems Engineer since the mid 1990s.
In recent years, there has been extensive (and ongoing) research into moisture in old buildings, and major changes in modern building construction. To keep my knowledge up to date, I subscribe to specialist technical publications, and attend a variety of courses and seminars. These are run by organisations such as the Society for the Protection of Ancient Buildings (SPAB), the Institute of Historic Building Conservation (IHBC), the Building Research Establishment (BRE), the Building Limes Forum, and the Institute of Specialist Surveyors and Engineers (ISSE).
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