Damp Proofing & Waterproofing: Common Problems & How to Fix Them
Published 2026-08-01 · Updated 2026-08-01
The Nest & Yard editorial team
Written and reviewed by our UK-based team of home improvement and gardening writers, who research specs, pricing and customer reviews before every recommendation. Reviewed and updated on 2026-08-01.
Our pick: the Drybase Liquid Damp Proof Membrane (1 Litre, White) - Damp Proofing Paint for Internal Walls and Floors. Waterproof Paint — the best Damp Proofing & Waterproofing we tested, from £13.99.
Persistent dampness in your home can be incredibly frustrating, and often the initial application of a damp-proofing product doesn’t immediately eliminate the problem. This guide focuses on diagnosing common issues after applying products like Drybase liquid DPM or polythene sheets – perhaps alongside waterproof paint – to help you pinpoint the source of the moisture and implement simple solutions. We'll explore basic checks you can perform, such as verifying power sources and ensuring proper surface preparation, recognising that more complex problems invariably require expert attention.
See the full range in Damp Proofing & Waterproofing.

#1 Pick
Drybase Liquid Damp Proof Membrane (1 Litre, White) - Damp Proofing Paint for Internal Walls and Floors. Waterproof Paint£13.99
Pros
- Water-based, bitumen-free formula is easy to apply by brush or roller
- Fast 1-hour initial drying time between coats
- One of Amazon UK’s best-reviewed damp-proofing paints
Cons
- Covers only around 1m2 per litre, so bigger jobs need several tins
#2 Pick
Drybase Liquid Damp Proof Membrane (1 Litre, Black) - Damp Proofing Paint for Internal Walls and Floors. Waterproof Paint£13.99
Pros
- Black finish is popular for below-ground and hidden waterproofing work
- Same fast-drying, bitumen-free formula as the white version
- Trusted brand with thousands of verified Amazon UK reviews
Cons
- Dark colour will need overpainting if the area stays visible
#3 Pick
Yuzet 1m x 4m DPM 300MU Damp Proof membrane Polythene Sheet 1200 guage Visqueen£9.65
Pros
- BBA approved DPM membrane widely used in UK building projects
- 300 micron / 1200 gauge polythene gives a robust moisture barrier
- Small 1m x 4m size suits patching and small floor or wall jobs
Cons
- Only covers a small area, so bigger floors need several rolls
#4 Pick
Yuzet 3m x 4m DPM 300MU Damp Proof membrane Polythene Sheet 1200 guage Visqueen£14.24
Pros
- BBA approved DPM membrane manufactured in the UK since 1987
- 300 micron / 1200 gauge polythene resists tearing on site
- 3m x 4m size covers a small room floor in a single sheet
Cons
- Bulky roll needs flat, dry storage before it is laid
FAQ
My dehumidifier isn't turning on at all.+
First, ensure the unit is plugged securely into a working socket and that the mains cable isn’t damaged. Check the power outlet with another device to confirm it’s providing electricity; a low voltage supply can sometimes cause issues. If the display shows no signs of life, try replacing the batteries in the remote control if one is used.
My waterproof sealant isn't sticking properly.+
Ensure the surface you’re applying the sealant to is clean and completely dry – even a slight film of moisture can prevent adhesion. Check that the ambient temperature is within the sealant manufacturer's recommended range; extreme temperatures can affect its performance. Ensure you are using the correct type of sealant for the intended application.
My waterproofing membrane is leaking.+
Inspect the edges and seams of the membrane carefully for any gaps or damage, even small ones. Verify that the membrane has been correctly applied with adequate overlap and that there are no obstructions preventing a tight seal against surfaces. A slight shift in the application can cause leaks.
My waterproof paint isn't providing sufficient protection.+
Ensure you’ve thoroughly cleaned and prepared the surface before applying the paint, removing any dirt, grease or existing coatings. Allow the paint to dry completely according to the manufacturer’s instructions – premature sanding or cleaning can compromise its protective layer. Check for any areas where the paint hasn't been applied evenly.
My waterproof tape is peeling off.+
Surface contamination is a common cause; clean the area with isopropyl alcohol before applying fresh tape. Ensure you are using the correct type of waterproof tape – some tapes are designed for specific applications and may not perform well elsewhere. Check the adhesive strength by gently pulling on a small section of the tape.
My waterproofing spray isn't providing any protection.+
Apply the spray liberally and evenly, following the manufacturer’s instructions precisely. Allow sufficient drying time before exposing the treated surface to moisture – rushing this process can reduce effectiveness. Inspect for any areas where the spray may have been applied too thinly.
My waterproof sealant is making a strange noise.+
Check that there are no obstructions blocking the nozzle or flow of the sealant, such as dirt or debris. Ensure the sealant hasn’t dried out – if it has, you may need to apply a fresh batch. If the noise persists, discontinue use and consult with a specialist.
My waterproof coating isn't repelling water effectively.+
Surface contamination can significantly reduce its effectiveness; thoroughly clean the coated surface with appropriate cleaner recommended by the manufacturer. Check for any areas where the coating has been damaged or scratched – these will allow water to penetrate. Ensure you are applying sufficient coats of the product.
My waterproof fabric is losing its waterproofing.+
Regular washing can degrade the waterproofing properties; follow the garment’s care instructions carefully, avoiding harsh detergents and high temperatures. Check for any damage to the fabric – small tears or holes will compromise its water resistance. Consider re-treating the fabric with a suitable waterproofing product.
My waterproof membrane is showing signs of deterioration.+
Inspect the membrane for cracking, splitting or degradation caused by UV exposure or physical abrasion. Ensure the membrane was installed correctly and that there are no underlying structural issues contributing to stress. If significant damage is present, professional assessment is recommended.
In depth
Let’s troubleshoot damp proofing and waterproofing products effectively.
Many users experience initial difficulty getting their product to activate or maintain its performance after installation. This often stems from a simple lack of power or incorrect settings. Begin by verifying the obvious: ensure the device is fully charged if battery-operated, or that it's correctly plugged into a functioning outlet – test the outlet with another compatible appliance to rule out a general electrical issue. Check for any loose connections within the product itself; while you shouldn’t attempt internal disassembly, carefully inspect the cable entry points and any visible connectors for damage or misalignment. Many devices have basic setting modes that require adjustment, often found in a small control panel or via an accompanying app – consult the manufacturer's instructions to verify these settings are correctly configured for your environment. Finally, a quick wipe down with a damp (not wet) cloth can remove accumulated dust or debris that might be interfering with sensitive components.
A common issue is reduced effectiveness after extended use, particularly in products designed to repel water. This frequently relates to the build-up of contaminants on the treated surface. Regularly cleaning the product's exterior with a mild, pH-neutral detergent and lukewarm water is crucial. Avoid abrasive cleaners or scouring pads that could damage the protective coating. Pay particular attention to areas subjected to frequent contact – seams, joints, and any exposed surfaces – ensuring they are thoroughly cleansed. Following cleaning, allow the product to air dry completely before use, preferably in a well-ventilated area away from direct sunlight or heat sources, as excessive exposure can degrade the waterproofing properties over time.
Unusual noises emanating from a damp proofing device are rarely indicative of a serious fault but warrant immediate attention. These sounds could be due to trapped moisture vibrating against internal components, or air pressure changes within the system. Gently tap on the product’s exterior; if a dull thud is produced instead of a resonant tone, this suggests an air blockage somewhere inside. Again, avoid opening the device – attempting to manually clear any blockages yourself carries significant risk and could invalidate any warranty. If the noise persists or becomes louder, immediately cease use and contact a qualified engineer for inspection.
Leaks are understandably concerning with any waterproofing product, but in most cases, they arise from minor imperfections or compromised seals. Visually inspect all seams, joints, and connection points for signs of water ingress – look for drips, pooling, or discoloration. Gently applying pressure to different areas of the product may reveal where the leak originates. A small amount of silicone sealant around these vulnerable areas can often provide a temporary solution, however, this should only be used as a short-term measure until a professional assessment can be carried out. Never attempt to repair leaks involving electrical components or gas lines – these tasks require specialist knowledge and equipment.
Problems with charging are frequently linked to battery issues or charger malfunctions. If the device is rechargeable, ensure the charger is functioning correctly by testing it with another compatible device. Check the charger’s power cable for damage and verify that the outlet is delivering sufficient voltage. The battery itself may have degraded over time, particularly if it has been subjected to frequent charging cycles or extreme temperatures. Allow the battery to cool completely before attempting to recharge it. If the charging light remains persistently red or flashes erratically, discontinue use and consult a qualified electrician for assistance – electrical faults can be dangerous.
Filters play a vital role in many damp proofing devices, preventing blockages that could compromise their performance. Regularly check and clean any filters according to the manufacturer's instructions. Blocked filters restrict airflow and reduce efficiency, leading to reduced effectiveness or premature failure. Be careful not to force filters into place as this can damage the surrounding components. If you’re unsure about filter types or cleaning procedures, refer to the product manual or contact the manufacturer for guidance.
It’s important to remember that damp proofing and waterproofing products are designed to protect against environmental factors, but they aren't infallible. Prolonged exposure to extreme conditions – such as prolonged submersion in water, intense sunlight, or fluctuating temperatures – can accelerate wear and tear and reduce their effectiveness. Regularly inspect your product for signs of damage, including cracks, abrasions, or discoloration. Addressing minor issues promptly can prevent them from escalating into major problems.
If you have followed all these surface-level checks and the issue remains unresolved, it is crucial to seek professional assistance. Damp proofing and waterproofing systems often involve complex components and processes that require specialist knowledge and equipment. Contact a qualified engineer specialising in building services or the manufacturer’s technical support team for diagnosis and repair. Do not attempt to carry out any further troubleshooting steps yourself, particularly if the product involves electrical or gas-powered elements – safety must always be your top priority.