When a DPC (Damp Proof Course) fails, the situation deteriorates rapidly and you must call in an experienced, qualified builder bricklayer who should assess the best solution. AbleSkills provides key bricklaying skills courses which offers the opportunity to undertake further building training leading to certificated qualifications right up to City & Guilds NVQ level.Damp Proof Courses fail for all sorts of reasons - sometimes, a DPC was not installed in the first place, as with older brick and stone built properties. One of the most common causes for a bridged Damp Proof Course occurs when earth or other materials have been piled against an outside wall. Water from the pile seeps into the wall above the DPC and begins to rise. By simply removing the soil/debris, the wall will be able to dry out naturally. Another reason may be due to incorrect installation, ageing or use of incorrect or sub-standard materials.Sometime debris, such as cement or mortar, falls away to the bottom of the cavity, forming a channel over the DPC for moisture to collect. Simply locating and removing the fallen debris should solve the problem. If the area is not found or immediately apparent due to a localised damp patch, it may be worth taking advice from a professional.There are several methods of replacing a DPC:Physical Replacement - the most expensive but also the most reliable. A mortar joint is cut out and an appropriate DPC material such as bituminised felt or heavy duty plastic sheeting is then inserted. This is highly specialist work involving structural alterations.Chemical Damp Course - this is a popular method which involves drilling a horizontal series of holes in the wall just above the failed DPC or if there is none, roughly six inches above ground level. A specialised pumping system forces a waterproofing chemical into the brickwork, entering the tiny 'pores' in the bricks and mortar, curing and forming a plastic-like barrier. Newer types of chemical damp course are available as a 'cream', which is injected using either a small hand pump or cartridge type mastic gun.An Electro-Osmotic Damp Course - a small electric current is passed into the wall, which flows downward, drawing water molecules in the same direction, and preventing damp from rising. A wire is installed, running along the wall with holes drilled at intervals to house metal anodes. A safe, low voltage current runs from the anodes through the wall to earth.A Clay Pot or Clay Tube damp proofing system - larger holes are drilled into the wall at greater intervals than a chemical damp course. A porous, hollow clay tube is then inserted into the hole, which acts like a wick, drawing water out of the wall to evaporate and eventually drying