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Damp Proofing Guide: How to Prevent Moisture Problems in Your Home
Our comprehensive damp proofing guide is designed to help you identify and address damp issues before they develop into costly problems.
By following our expert advice, you can prevent long-term damage to your property and ensure your home remains dry, safe, and protected from dampness. Finding and preventing the source of moisture is key to protecting your property. If you need professional damp proofing advice, our fully trained and qualified specialists can diagnose the issue in a detailed report backed by evidence and recommend a treatment plan if any work is necessary.
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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 (DPC) 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. These damp proof courses can be bridged by external cladding, flowerbeds pushed up against the brickwork or through heightened ground levels.
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.
Condensation is the most common cause of damp walls as warm moist air condenses on cold surfaces, such as bathroom mirrors. However moisture can condense on walls if the surface is cold enough. Increased ventilation helps remove this excess moisture, and there are ways to improve the thermal temperature of a wall.
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 Treatment Services
How Much Does Damp Proofing Cost?
Damp proofing is unique to the property its effecting, meaning there can be many variables that have an effect on the price of work being carried out.
The first step to understanding the issue is to get a trained and qualified professional to conduct an extensive survey of your property. They will be able to diagnose the problem and correctly identify the type of damp with recommendations for work, if necessary. You should always use a qualified professional and avoid companies who are willing to give you a price without fully understanding the extent of the problem.
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?
When you invite a tradesperson into your home to conduct a damp survey or treatment you want the peace of mind that the issue is diagnosed correctly, and fixed for good.
Our treatments are backed by 30-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.
Frequently Asked Questions
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What is the difference between damp proofing and waterproofing?
Damp proofing prevents moisture from entering a building typically through a wall or floor, while waterproofing is used for below-ground spaces such as basements to protect them from hydrostatic pressure, moisture vapour and ground moisture.
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Can I treat damp problems myself?
Minor damp issues like condensation can often be addressed with DIY methods. However, for more serious issues such as rising damp and penetrating damp, it’s best to consult a professional to correctly diagnose and treat the problem.
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How long does damp proofing treatment take?
The duration depends on the size and complexity of the problem. Typically, a DPC injection takes one to two days, while more extensive treatments like membrane installation may take longer.
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 by clicking the button below to get a quote for a damp proofing survey.
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