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Damp Proofing

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Damp Proofing

Our damp proofing guide has been designed to help you identify and repair damp issues before they turn into major problems that require expensive treatment to rectify.

If you feel that you would benefit from professional damp proofing advice to diagnose the issue and create a custom treatment plan to leave your home fresh, safe, and dry, then you can talk to our fully trained and qualified specialists by clicking the button below.

Rising Damp Survey

What is Damp Proofing?

Damp proofing is a general term that covers methods and treatments used to prevent water or moisture being absorbed through walls or floors into the interior of a property.

The method of treatment you require varies depending on the underlying cause of your issues, whether that is rising damp, penetrating damp, condensation, or even water ingress in a basement or cellar.

If you are unsure if your home may need professional help, you may want to consider requesting a professional damp survey to accurately diagnose the problem and create a treatment plan for you.

What are the Signs of Damp?

Damp problems can vary in appearance and severity,  so it can be difficult to identify exactly what is causing the stains and patches on your walls. We would recommend getting any signs of dampness checked out by a professional, particularly if you notice any of the following:

  • Wet and damaged plaster.
  • Wallpaper peeling from the wall.
  • Musty/mouldy odours.
  • Black mould on the walls and windowsills.
  • Damp stains rising from the ground floor to about one metre in height.
  • Walls that feel damp to the touch.

What Causes Damp Walls

Most properties are built with a polythene sheet or bitumen slate damp proof course pre-installed to prevent rising damp problems. This can often be seen a few inches above ground level in the brickwork of your property, and the breakdown, degradation or failure of this course is one of the most common causes of rising damp.

Damage to other parts of your property that control humidity and ventilation or water management such as air bricks, gutters and drainage can also lead to problems like penetrating damp and condensation on walls.

Different Types of Damp Explained

The problems and signs listed above are caused by either water ingress from an external source, groundwater rising into the wall through capillary action or inadequate ventilation.

Our guide will now go on to look at those different types of damp to help you identify the cause of damp walls in your home and if you need a professional damp survey to accurately diagnose the problem and create a treatment plan for you.

How to Spot Rising Damp

Rising damp will only occur when an existing damp proof course (DPC) has been bridged or damaged in some way. This allows rainwater in the ground to seep into the building through bricks and mortar by a process called capillary action.

It is important to note that it will only ever affects the ground floor, and symptoms on internal walls include:

  • Damp walls and a ‘tide stain’ above the skirting board
  • Evidence of salt deposits left on the wall
  • Damaged or rotting skirting boards, plaster and wallpaper

Penetrating Damp

Water leaking in from outside the property is the main cause of penetrating damp. This will usually manifest as localised damp patches on a wall or ceiling.

Broken downpipes and gutters, cracks, faulty joints and corroded seals are all contributing factors. Leaks from inside can cause problems too, and wet rot or related issues like woodworm can often accompany damp from faulty plumbing or leaking washing machines and showers.

The signs of penetrating damp are:

  • Visible damp or even moss growth on external walls
  • Walls and ceilings with damp above the first floor
  • Wet plaster (if over 1m high)

Condensation on Internal Walls

Condensation is caused by excess humidity and poor ventilation. It also creates ideal conditions for black mould to grow.

Look out for excessive moisture or water droplets and black spot mould around:

  • Walls, ceilings and attics
  • On furniture, curtains and other soft furnishings
  • ‘Hotpoints’ like bathrooms and on or around windows

How to Damp Proof your House

Now that our guide has helped you to spot the signs  and identify which is present in your home, we will now look at the various types of damp treatment and which one is right for you.

Install a Remedial Damp Proof Course

Most properties should have evidence of a Damp Proof Course about 150mm (6inch) above ground level. This may be seen as a slightly thicker mortar course with evidence of a slate or bitumen sheet. These materials are fairly resilient, however, they can degrade, become damaged or bridged by modifications, leaving your home vulnerable to rising damp.

To damp proof properties affected by this, the most common solution is to inject a silicon remedial damp proof course which creates a waterproof barrier, effectively preventing moisture from seeping into, and damaging, affected walls. DPC injection is a fast-acting and permanent method of damp proofing and allows affected walls to be redecorated shortly after installation.

Damp Proofing External Walls

Naturally, the first step is to solve the issue that is allowing the water ingress in the first place. In some cases, this just requires a simple DIY solution to solve faults such as a damaged roof tile or crack in the external wall, although it may be the case that a professional restoration service is required.

Frequently the homeowner will be required to strip the affected area of the plaster and to install a layer of damp proof membrane in the wall before replastering.

Unfortunately, this type of damp has the potential to create more serious issues like wet or dry rot, so we would suggest that you should thoroughly investigate the property for signs of rot or associated damage before attempting to replaster the wall. Otherwise, you may install damp proofing measures required to fix the initial cause, while much worse issues continue to fester inside the property.

How to Treat Condensation Problems

The key to damp proofing properties affected by condensation is achieving consistent relative humidity. This can often be remedied with DIY or lifestyle changes, but in serious cases treatment will require a coating with anti-condensation paint or the installation of mechanical ventilation units.

Damp Proofing Basements and Cellars

Damp or flooding in an underground space like a basement or cellar usually comes under the heading of waterproofing rather than damp proofing.

At Rentokil Property Care we also provide a full suite of waterproofing treatments, including the application of basement tanking and cellar slurry, damp proof membranes and sump pump installation that you can read about on our basement waterproofing page.

How Much Does Damp Proofing Cost?

Due to the number of variables that have a direct impact on pricing, we cannot provide a damp proofing estimate without visiting the property.

To give you an accurate quotation, one of our CSRT and CSSW qualified surveyors will conduct an extensive survey of your property.

The list of factors that will contribute to the overall cost of damp proofing are:

  • The size and extent of the issue within your property
  •  The type of damp proofing treatment required will determine the overall costs of our services
  • Removal of plaster and subsequent replastering will also add to the cost of any damp proofing work

Do Our Damp Treatments Come With a Guarantee?

Inviting any expert into your home to conduct a damp survey or tradesperson to provide a damp proofing or damp treatment service requires that you can have absolute certainty that they will accurately identify and repair the issue so it will be fixed for good.

Our treatments are backed by 20-year guarantees and our long and established history in the industry dating back over 60 years enables you to have complete peace of mind and certainty that, in the unlikely event that something should go wrong and you find the problem returns, we will be able to send a damp proofing professional to repair your walls and return your home to its natural dry state at no extra cost.

For extra security we also offer a range of insurance policies for other property problems such as woodworm, dry rot or wet rot.

Certified Damp Proofing Surveyors and Technicians

All of our surveyors are highly trained professionals in remedial damp proofing for residential and commercial buildings. We are accredited by many trade associations, certifying us as one of the most reliable and effective property care experts in the UK.

Our specialists are not only able to provide an expert service; they also keep you in the loop throughout the whole restorative process – explaining the procedures to make sure you’re both completely on the same page.

Contact Your Local Damp Proofing Specialists

Our local branches of Rentokil Property Care are waiting to take your calls and online enquiries to provide all the guidance, advice and help you need to get started damp proofing your home.

Quite simply our long and distinguished record of success, long-lasting guarantees, and outstanding customer reviews mean that there is no better company out there for you to entrust the health of your home to. Contact your local branch today on 0800 0121 437 or click the button below to get a quote for a damp proofing survey.