All of our work is mostly putting other contractors poor workmanship right, so I thought after discussions with clients about the the poor diagnosis that they have been receiving and poor standard of reports I would put a blog post on what you should receive when you get a damp and timber report. Also note that a basic damp and timber survey of a 3-4 bed house should take around an hour.
Below is the British Standard that all of the damp reports and specifications should comply to.
BS 6576:2005 Code of practice for diagnosis of rising damp in walls of buildings and installation of chemical damp-proof courses.
The British Standard gives guidance and recommendations on the diagnosis of rising damp in walls of buildings, in particular to the need to differentiate between rising damp and other sources of damp, and the consequent installation of chemical damp-proof courses (dpc’s) in walls of buildings where rising damp has been diagnosed. Structure and cost often prelude fitting of physical damp-proof membranes in these circumstances.
The object of installing a chemical dpc is to reduce rising damp, or the risk of rising damp, to acceptable levels, by creating a horizontal barrier to rising damp at the correct level in the wall.
When drafting of the British Standard it has been assumed that the assessment and diagnosis of rising damp will be conducted by appropriately qualified and competent surveyors and the installation of the damp proof course system and the associated re-plastering will be conducted by trained operatives under the direction of qualified surveyors.
Assessment of buildings
Before installing a chemical damp proof course, it is essential to establish:
a, whether rising damp is present
b, whether the building is suitable for treatment using the particular system proposed
c, whether the building is currently being modified and , if so, the effect of this work on the proposed chemical damp proof course
Installation should only be carried out if the assessment recommends this.
When inspecting a structure for signs of rising damp, it is essential to take into account the possible presence of other sources of dampness. Even if the instructions given are limited to the detection of rising damp, other problems should be highlighted if they are present and reasonably obvious.
Visual observations both externally and internally are important and can provide much of the information needed to arrive at a preliminary diagnosis. Nevertheless, a full understanding of the distribution of dampness in a structure can require the use of various moisture measuring techniques. An electrical moisture meter is a useful diagnostic instrument: it can be used to discriminate between different explanations for damp conditions, and is non destructive. The readings given are qualitative. Surface moisture measurements alone cannot give proof of rising damp, so further evidence may, where permitted, be obtained by disruptive examination and measurements taken within the depth of the wall.
The only way to carry out a quantitative test is to take samples and carry out a gravimetric test to BRE Digest 245 with salt analysis. This will the show the exact free moisture dampness in the wall, hygroscopic salts, if nitrates and chlorides are present. With this profile you can see the height of rise and the distribution of salts if there is true rising dampness. Many so called damp specialists will offer there services using a carbide meter or speedy meter, as detailed in BS 6576:2005 chemical tests on site from these which can only show the total moisture content, this will not give you the correct diagnosis. What we need is to test the capillary moisture content % and the hygroscopic moisture content % this will then give us the quantitive results needed (BRE DIGEST 245)
Below is the results from a gravimetric profile to BRE Digest 245, this shows that rising damp once had risen to 500mm and shows that nitrates and chlorides are present.
|Height (mm)Off floor||Material||TotalMoisture Content %||HygroscopicMoisture Content %||CapillaryMoisture Content %||Chloride||Nitrate|
It states in BS 6576: 2005 that, all findings and assessments should be comprehensively documented and conveyed in a written report and should include the following
Clients name and address of surveyed property
Date and date of survey
Instruction e.g. Inspect the front left hand party wall of the living room for rising damp only
Type of property
The limitations-restrictions of the survey
External observations to include pictures
Internal observations to include pictures
Recommendations / Discussion
Client’s responsibilities before work starts
Contractors work to be carried out
Client’s responsibilities after contractors work is completed
Cad drawing-sketch plan detailing what treatment and where
Type of guarantee
Price of works
Surveyors name and qualifications and Property Care Association registered number
Health and safety info
A report that is detailed like the above will give you confidence in the surveyor-contractor as it will explain what the problem is and the specifications of works if needed.
The report will protect the client in the future and the contractor if a dispute should arise as you can clearly see what works have been done and where, especially simple things like the client is to lower the high external ground levels and fix the leaking guttering etc. This is why most of the damp proofing guarantees cause disputes as a poor report written for the previous owner of the property, I have found the contractor seems to try and wriggle out of the claim.
Most of the damp proof course failures that I come across the report is simply a quote, it’s 1 or 2 pages with no diagnosis or pictures detailing what the surveyor has seen or recommended, a poor specification and a price with a hand drawn sketch plan. When I actually speak to them and explain my concerns about the quality of the work and the report they always say well I thought they were qualified surveyors! Unfortunately the damp proofing industry has rogue traders that are not qualified specialists as they claim on their websites, the good news is these damp proofing contractors are being found out.
Many companies claim to be approved by a chemical manufacturer, it doesn’t make them qualified as they haven’t taken an industry exam, they probably have no insurance and will not be able to offer a GPI Guarantee on their works.
Complete Preservation are 1 of only 5 people in the UK that carry out quantitative damp diagnosis to BRE Digest 245 and being qualified, along with our experience and qualification in thermal imaging we offer a service that makes us experts in finding the real problem and a long term insurance backed guarantee on our remedial works.
In the below picture our surveyor Ross Charters is presenting to 200 Chartered Building Surveyors (RICS), on why BRE Digest 245 is so important on understanding rising damp and hygroscopic salts. Ross Charters was asked by RICS as he undertakes many destructive surveys to BRE Digest 245.
To contact Complete Preservation of Trowbridge Wiltshire to discuss about a damp or timber survey.