We have said this many thousands of times: "You do not need a chemical damp proof course" As you will see from the website, a breathable house is a dry house. There's also a huge amount of information on the Heritage House website about the damp industry in general, and the fraudulent practises involved.
Chemical damp proofing is a peculiar practise almost exclusive to the UK. I have lived all over the world, and never seen chemical damp proofing in any other country. It is sold and promoted by a huge public marketing exercise which a a giant con trick. The chemical damp proofing industry is run by the Property Care Association which claims to 'train' operative and surveyors. In reality, the 'qualifications' of CSRT and CSSW are meaningless - they have no academic status, and are wielded by chemical sales people who have no formal academic education or training in building pathology. Principal member companies of the PCA include Peter Cox, Rentokil, Timberwise, Kenwood.
You do NOT, ever need damp proofing. The simplest, and cheapest way to achieve a dry house is to remove modern materials, ventilate it well, and make sure you remove moisture when you create it - showers, and cooking being the main problems. Don't dry washing on radiators in the house!
A particular problem you may encounter in the survey industry is an almost religious demand by certain survey chains doing valuation surveys that a 'timber and damp' survey is carried out by a PCA member. Do NOT go along with this. Insist that a professional examines your house as part of a proper structural survey - not an untrained monkey from an organisation with zero academic credibility.
A typical 'damp' wall that the damp industry will tell you is wet and needs injecting. Well guess what - it is all just temperature related condensation. Now the contained moisture has blown out of the wall, it is dry. The next photo shows a drill sample of the wall:
Sample drilled from the wall in the photo above, and tested for total moisture content in a carbide chamber. It's less than 2% total moisture - in other words, bone dry. No damp in here at all. No need for ANY damp proofing.
The interesting thing about this example is that the water table is only 6" below the base of the wall, which is a solid limestone wall, built with soft lime mortar.
