Damp proof Issues

When building certain things like e.g houses extensions garages , well almost anything that is going to be lived in or used for storage, or work related, you have to put a damp proof layer minimum depth of 150mm above ground level, any less and you might start having damp issues with your property,and other unforeseen problems. A damp proof layer, or course in building terms , is a layer of PVC or an high grade ruberoid , that is placed around your foundations at the same level as your house, or extension floor level . This forms a very affective and impenetrable barrier to stop rising damp, moisture will not penetrate above this, but I have through my own experience have been to clients homes who wish to have an extension to there homes, have built themselves patios, decking etc etc above there damp proof course, which is a no no , its there for a reason to stop damp and once you go above the damp proof course you going to get all sorts of problems, if prolong spells of rain in the winter months or early spring start, you will most likely get rising damp , which can run up your House walls to an height of 1 metre which is not a good sign, and do untold damage to your brickwork, that's why today we have to build below DPC with a very hard and damp resistant brick known as an engineering or semi engineering brick, in the early 1960s to the late 1970s possibly as late as even the 1980s the mass produced housing market used a brick known as a London brick below and above ground , let me tell you they are rubbish below and above ground , but thousands and thousands of homes were built with these bricks , and below ground , over a matter of a few years they would crumble and perish . the Victorians were masters of damp proofing for the technology of there day they use to use lead and slate and very hard blue bricks ,this was very effective against Damp.