Damp Proof Courses: What Are They & Different Types of DPCs

Damp Proof Courses
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Water damage is a massive hassle for landlords and can inconveniently strike when you least expect it! Water damage can not only be expensive and time consuming to fix, but can (in extreme cases) leave properties unable to house tenants.

Utilising a damp proof course (DPC) is the most effective way to protect you property against possible water damage.  A (DPC) damp proof course prevents moisture from rising through a property’s floors and walls. Excess moisture can be extremely damaging because it affects plaster and can cause discolouration. Too much moisture within a property can also cause timber to dry/wet rot. There are several different types of DPC – with each having it own unique benefits depending on your property and situation.

  • DPC Injection – Installing this damp-proof course involves injecting a liquid or cream into the walls. It repels the water from the ground so that water does not rise above the DPC level. To inject the chemical requires drilling holes in the wall. The chemical is generally silicon-based and often commonly used for masonry works. This method of DPC works more effectively than a solid DPC.
  • Electro Osmotic DPC – This DPC is best suited for historical/older buildings. It works effectively if the wall is filled with rubble and stone. It pushes water back down to the ground via a positive electoral charge.
  • Damp Proof Membrane – A damp proof membrane is placed under concrete slabs and prevents any moisture from seeping into the concrete. This (in theory) should make the concrete free from moisture. This DPC works best when the walls are unfinished or not yet plastered.
  •  Pressure Grouting – This method is most commonly used when repairing hardened concrete. A mixture of cement, sand and water is combined to fill in any cracks in the structure. In order to fill wider gaps, grout is needed and poured in at high pressure.

  • Cavity Wall DPC – You can install cavity wall DPC as insulation. It works by ensuring continuous air space between two parallel walls. Metal is used to tie the wall to maintain the required gap to prevent dampness. However, sometimes the gap in between the two walls can accumulate moisture that eventually leads to dampness.
  • Chemical DPC – This course of action is normally taken after one of the aforementioned DPCs has failed or deteriorated. A water repelling chemical is injected and creates a vertical and horizontal barrier. This prevents any movement of moisture.


It should also be noted that not every property needs a DPC. Happily, not every property owner has to deal with water damage  – but knowing how to spot dampness issues early on is half the battle. Below are some signs to watch out for, that would suggest you need to consider a DPC of some sort.


  • Interior walls show some form of black mould
  • Watermarks have formed on the walls
  • There are signs of plaster peeling
  • Wood within the housing structure is deteriorating/showing signs of rot

It’s essential to catch dampness and moisture issues before they lead to serious problems. If dampness is visible in any of your properties we would recommend the best thing to do is call in the services of a professional.

Octo is your free property management software application and prides itself on offering landlords & investors advice on all property related matters.