Basement of a house being damp proofed

How to Damp Proof A Basement?

Key Takeaways

Importance of Basement Maintenance: Basements are prone to water seepage and damp issues, posing a risk to the entire property if not well-maintained. Signs like cracks, mold, or pipeline leaks should be addressed promptly.

When Damp Proofing is Required: Damp proofing is needed when constructing a new basement or when the previous damp proofing has eroded. Frequent reapplication may be required in regions with higher soil moisture.

Methods of Damp Proofing: Damp proofing involves various methods such as membranes, foundation tar, protective sprays, bitumen dam-proofing, cavity drain membrane systems, paints, and sealing cracks. Each method has specific applications and considerations, such as membrane placement, spray-on chemicals, and bituminous substances.

The basement is the area of the house that is most prone to water seeping and damp issues. For this reason, you have to take all the preventative measures that you can. Once damp hits the ground in the basement, it becomes challenging to get rid of it.

Also, treating damp in the basement or cellar area costs a lot of money and can also consume more time. The basement is like the base foundation of the property, and if it is not well-maintained, you are risking the entire property.

So, make sure the basement of the property is clean from potential damp-promoting factors and does not show any signs of damage. There must be no cracks, mould, or pipeline leaks in the basement. Another thing that can be done is the damp proofing of the cellar walls.

Let’s see how you can do all of that.

Peeling of paint work due to rising damp

When is Damp Proofing of Basement Required?

Because many damp proofing treatments are transient, frequent reapplication may be required over the course of several years. The use of a damp proofing system is prevalent in regions characterized by having higher soil moisture, making it an adequate measure in such climatic conditions.

Here’s more on when damp proofing might actually be required:

When Constructing a New Basement

When constructing a new home, the builder will apply damp proofing to prevent structural damage for many years.

When the Previous Damp Proofing Has Eroded

Even in new buildings, damp proofing may deteriorate over time. Some resourceful homeowners choose to do it themselves, as it’s a relatively simple skill to learn. However, it is not recommended for DIY as it has more technical aspects of its own.

Bubbling of plaster on a wall due to damp

How is Damp Proofing of a Basement Done?

Damp Proofing Membranes and Courses

Membranes, well-known for their effectiveness in damp-proofing walls, include strategically placing a water-repellent concrete barrier between the foundation sensitive to soil moisture and the foundation adjacent to the issue zone or an exterior basement wall.

Also, a damp-proof course is applied either horizontally or vertically to waterproof basement, depending on the specific needs of the circumstance. This procedure is generally applicable to basements and crawlspaces, the latter of which is popularly referred to as tanking.

Use of Foundation Tar

Foundation tar is a popular solution for improving the damp-proofing qualities of outside foundation walls. It performs the function of forming an impenetrable waterproof covering, preventing moisture entry.

Its applicability is especially relevant in inhospitable locations, such as crawlspaces. Notably, foundation tar, in addition to its functional function, lends a visually distinct black tint to the foundation, adding to an improved aesthetic appeal in these structural elements.

Damp moisture on a wall

Protective Sprays

Using a spray-on chemical application is quite effective in reinforcing brick and stone walls by imparting an extra layer of moisture-resistant coating, protecting against the adverse effects of residual moisture. It is important to note, however, that this approach fails when exposed to pressured moisture conditions.

The solution sprayed into the pores of the wall contains a broad assortment of water-repellent chemicals that have been precisely selected to prevent any water intrusion into the basic structure.

To guarantee the best efficacy, however, careful consideration of the chemical composition used is required, as is strict adherence to exact application methods.

Bitumen Dam-Proofing

Bituminous damp proofing is an approach for preserving the structural integrity of your home’s foundation.

This method comprises the use of substances, such as bitumen or asphalt, which have an inherent feature of excellent stickiness and profound resistance to moisture infiltration.

This damp proofing method, widely praised for its adhesive power, has a predisposition to readily stick to various foundation materials, consequently strengthening the overall robustness of the fundamental structure.

Cavity Drain Membrane Systems

Using a side cavity drain system or membrane system is another method to damp-proof the basement, which involves fixing a membrane to the walls that allows water to drain into a cavity or channel. This system directs water to a sump pump or drainage system, effectively managing water ingress.


Applying damp-proof paints to the interior walls of the cellar or basement also helps against damp. These products create a water-resistant barrier on the surface, preventing moisture from penetrating.

However, before using this method, one must make sure that the walls are properly prepared and that any existing damp or efflorescence is addressed before applying these coatings.

Seal Cracks and Gaps

To perfectly damp-proof the basement, you can also seal any cracks, holes or gaps in the basement walls using appropriate sealants. It prevents water from seeping through these openings. Addressing these small openings is crucial for effective damp-proofing.

Ceiling affected due to penetrating damp

Who Performs Damp Proofing?

Damp-proofing specialists handle damp proofing when it comes to the construction of a new basement. They address damp proofing in new builds while also taking it when existing structures face issues.

Since damp-proofing is crucial for a home’s foundation, homeowners often choose licensed damp-proofing specialists over DIY methods for their damp-proofing and waterproofing requirements.

Rising damp and moisture on a wall

Can Damp-Proofing of a Basement Be Done DIY?

Because damp-proofing is so simple, many homeowners prefer to install it themselves, employing a large amount of available damp-proof mixtures and kits mainly intended for this purpose.

For individuals with handyman abilities, doing this work on their own appears to be the most practical and realistic alternative. However, someone who does not know much about it must hire a damp-proofing specialist to get it done.

House surveyor surveying a house

What are the Benefits of Damp-Proofing a Basement?

Damp-proofing a basement offers several advantages for the overall well-being and durability of a building. Here are the key benefits:

Structural Protection

Damp-proofing prevents moisture from entering basement walls and floors, reducing the risk of structural damage like wood decay, metal corrosion, and masonry deterioration.

Mold and Mildew Prevention

By lowering moisture levels, damp-proofing helps prevent the growth of mould and mildew, ensuring better indoor air quality and reducing the risk of respiratory issues.

Increased Property Value

Well-maintained, moisture-free basements enhance property value, making it more attractive to potential buyers and avoiding liabilities associated with damp problems during transactions.

Energy Efficiency

Damp-proofing contributes to improved energy efficiency by retaining insulation effectiveness, making it easier to maintain a comfortable and energy-efficient temperature within the building.

Odor Prevention

Damp-proofing reduces moisture, preventing the musty and unpleasant odours often associated with damp conditions in basements.

Penetrating damp and mould on interior of the roof

When to Call a Damp-Proofing Professional?

If you are unsure about your understanding of the full scope of water-related issues in your home and your ability to adequately address them on your own, consider hiring a seasoned professional specializing in damp-proofing.

Many damp-proofing service providers provide free evaluations to determine the extent of the damage and provide an estimate of the costs involved with repair work.

Also, you can hire a damp surveyor first to decide whether the basement floor requires damp-proofing or not.

Should their inspection find significant basement leaks resulting in structural compromise or a pressing need for fundamental repair, it would be essential to get the assistance of a competent professional to complete the necessary fixes.

Black mould spots on a wall

How do I stop my basement from being damp?

To keep your basement dry, fix leaks, maintain good drainage, use a sump pump, apply waterproof sealant, enhance ventilation, and repair cracks with moisture-resistant materials.

How do you damp proof basement walls from the inside?

To damp-proof basement walls from the inside, clean and prep the walls by removing paint and contaminants. Apply a top-notch waterproofing sealer or membrane, and consider using specialized waterproof paint or cementitious coatings. Keep the basement well-ventilated during and after application, following the product instructions for optimal results.

Can I waterproof my basement myself?

You can waterproof your basement on your own if the work is not too extensive. Simple tasks like fixing small leaks, using waterproof sealants, and improving drainage can be done by homeowners. However, for more complicated issues, like major foundation repairs or advanced waterproofing systems, it’s recommended to seek help from professionals. Before beginning any DIY waterproofing project, make sure to research methods and products thoroughly, and follow safety guidelines.

How do I keep moisture out of my basement walls?

To prevent basement walls from getting damp, take steps both externally and internally. Outside, focus on grading, gutters, and downspouts to divert water away. Apply waterproof sealants to outer walls. Inside, use dehumidifiers, add a vapor barrier, and fix any cracks promptly. Opt for moisture-resistant materials when finishing or remodeling your basement for better protection against dampness.

Table of Contents

Picture of Sam Fitzgerald – CSRT Damp Surveyor

Sam Fitzgerald – CSRT Damp Surveyor

Author – CSRT Damp Surveyor
Sam is a highly qualified and seasoned damp surveyor with over ten years of specialised experience. With a strong academic foundation in building surveying and numerous professional certifications, Sam has established himself as an authority in the field of damp diagnosis and remediation.

At Damp Surveyors Ltd, Sam applies his extensive knowledge to help homeowners across the UK address and solve their damp issues effectively. His approach combines cutting-edge techniques with a commitment to honest, client-focused service, ensuring that every survey and recommendation is tailored to the specific needs of the property.

As a thought leader, Sam’s insights into damp prevention and treatment have been featured in industry publications, underscoring his role as a trusted expert dedicated to maintaining the integrity and comfort of your home.

Testing device for measuring dampness in a house


At Damp Surveyors Ltd, we stand out as your premier choice for damp survey services in the UK. Our commitment to excellence and customer satisfaction sets us apart. Here’s why you should choose us:

  • Exclusive 3 Free Quotes: We offer a one-of-a-kind optional service where you not only get our top-notch damp survey but also receive 3 free quotes from vetted local companies, giving you peace of mind by saving you thousands on getting the most competitive quotes, and also time researching and contacting other reputable companies.
  • Knowledge and Experience: We provide unmatched knowledge to every survey we conduct thanks to our team of seasoned professionals and years of industry experience. This guarantees accurate assessments and practical solutions.
  • Nationwide Coverage: Whether you’re in a bustling city or a rural area, our services extend across the UK, making us accessible wherever your property is located. Choose us for nationwide reliability and excellence.

Choose Damp Surveyors Ltd as your reliable partner for all-inclusive survey needs. Our top concerns are the health and safety of your property, and we are committed to providing outcomes you can trust.

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