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What is Damp Proofing, and How Does it Work?

When it comes to acquainting yourself with different aspects of damp and its treatments, one of the first terms you may encounter is “damp proofing.” To protect your home from the causes of rising damp and penetrating damp, including seasonal damp problems, a suitable damp proof course (DPC) must be in place. A DPC is one of the most imperative features of a property, as it inhibits moisture from rising from the ground.

Damp issues when selling/buying a property can be detrimental to the home’s value. Excess moisture in a property can affect the plaster and decoration and can even lead to woodworm, and wet or dry rot in timber. The way damp affects your property’s valuation is just one of the potential problems; damp can also harm your home’s structural integrity.

Due to the severity of the impact that damp can have, most properties have a DPC installed. Despite this, dampness in historic buildings can pose a real risk, as DPCs were not common practice until 1875. Therefore, if your house is around 150 years old, and your DPC hasn’t been renewed any time recently, it could be susceptible to damp problems.

Different Types of Remedial Damp Proof Courses

There are three main types of remedial damp proof course, and the construction of your property will determine which is most suitable for your home.

The first is a damp proof course injection, describing a liquid or cream injected into the wall. This acts as a water-repelling layer, which inhibits damp from rising above the DPC, and is often referred to as a chemical damp proof course injection. The process involves drilling holes into the wall at least 150 mm above external ground level and filled with the water-repelling cream.

Next up is a mortar injection damp proof course, which bears similarity to the damp proof course injection, as it’s also injected into the wall. Despite this, a chemical-enhanced mortar is used instead of liquids or creams. This is the most appropriate course of action when the property is constructed from rubble, resulting in structural gaps.

Last but not least is an electro osmotic damp proof course, which is employed when chemical use isn’t appropriate or approved. This involves the use of titanium and copper wiring, which provides the wall with a minor electric charge. Consequently, the polarity of the capillarity is reversed, and the rising damp is pulled below the DPC.

Do All Properties Have a Damp Proof Course?

As previously mentioned, DPCs became compulsory in 1875; however, this doesn’t necessarily mean that all structures built after this year are covered. As you can imagine, DPC technology has come a long way in the last 147 years. The original DPCs laid after 1875 may no longer serve their intended purpose.

Originally, lead, or slate barriers were fitted into the walls to create a DPC. Since then, DPCs evolved to include bitumen felt and eventually plastic. As a result, old DPCs may fall victim to bridging, damage, and deterioration, meaning that a new DPC may be required.

Upon noticing signs of rising damp, some homeowners invest in damp-proof paint and deem this an effective DPC. Despite this, damp-proof paint won’t provide your property with the protection it needs against rising damp. Instead, it may only temporarily mask the problem and perhaps offer you a short-term solution, but for complete protection, you need a suitable DPC.

What Causes Damp Walls

In order to solve your property’s damp issue, you must first identify where the moisture is coming from. Garratt’s Damp & Timber Ltd offers a free site survey, in which we can inspect your property in its entirety to identify the source of damp problems.

Some of the most common causes of damp issues include:

  • External flooding
  • Faulty drains
  • Plumbing leaks
  • Faulty DPC
  • Insufficient door and window pointing
  • Faulty cavity wall insulation
  • Condensation problems
  • Defective exterior masonry or render
  • Faulty downpipes, gutters, or roof coverings
  • Ground levels that have historically increased and bridged the physical DPC

If you believe that your home is suffering from damp, it’s vital that you get the diagnosis confirmed by a professional. Without this specialist confirmation, you may end up paying for unnecessary remedial work.

How to Identify Damp Walls

When identifying damp walls, inspect your property’s interior and exterior for any defects. If you notice any signs of damp, you might use a moisture meter, which can inform you whether your home’s moisture content is above average. Following this, you should always get in touch with a damp and timber specialist to assess and diagnose the issue.

Damp Proofing Cost

Unfortunately, it’s difficult to say how much damp proofing costs, as every property is unique and will have a different set of requirements.

What Next?

If you’re concerned about damp in your property, be sure to have your home surveyed by a professional. Get in touch with Garratt’s Damp & Timber Ltd. to arrange your free site survey and obtain a quote for any required work.

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