The cost of basement construction depends on several factors, including the size of the basement, the ground conditions, the intended use of the space, and the waterproofing system required. Every project is unique, so we recommend arranging a professional survey, where one of our experienced surveyors can assess your property and provide a detailed, no-obligation quotation tailored to your requirements.
Emergency Waterproofing
Urgent Help for Basement Flooding, Leaks and Water Ingress
Request a call
Emergency Waterproofing London
Our experienced specialists will assess where the water is entering, identify the likely cause and recommend the work required to bring the problem under control and protect the property against further damage.
Do not wait for water ingress to become more extensive. Call our waterproofing team now to discuss the problem and the earliest available assessment.
Call 020 3795 4900
or
Request an Urgent Waterproofing Assessment.
Need Urgent Help With Basement Water Ingress?
Basement and cellar water ingress can happen suddenly, particularly during periods of heavy rainfall, groundwater pressure, drainage failure or pump failure. In other cases, a minor damp patch or occasional leak may gradually develop into a more serious problem.
Because basements are below ground, water can enter through walls, floors, construction joints, service openings and defects in an existing waterproofing system. Removing the visible water may provide temporary relief, but it does not resolve the underlying cause.
Our waterproofing specialists can investigate problems including:
Active water entering a basement or cellar
Basement flooding following heavy rainfall
Water rising through the basement floor
Leaks through basement walls
Water entering at wall-to-floor joints
Failed cellar tanking systems
Damaged or blocked cavity drainage systems
Failed sump pumps or pump alarms
Unexpected damp, mould or standing water
Water ingress affecting plant rooms or commercial premises
If you can see active water ingress, call us on 020 3795 4900 and explain what is happening. Our team will advise you about the earliest available assessment.
What to Do When Water Is Entering Your Basement
Your immediate priority should be the safety of everyone in the property.
Keep children, pets and other occupants away from the affected area.
Do not enter standing water if electrical sockets, appliances or wiring may be affected.
Do not touch electrical equipment while standing in water.
If it is safe to do so, move valuable or water-sensitive belongings away from the affected area.
Take photographs or videos of the water ingress and any visible damage.
Check whether an installed sump pump is operating, but do not dismantle electrical equipment.
Contact the emergency services or relevant utility provider if there is an immediate danger to people or the property.
Call a specialist waterproofing company to investigate the source of the water.
Never put yourself at risk to inspect or remove water from a flooded basement.
What Causes Sudden Basement Flooding?
Water ingress can have several causes. Correctly identifying the source is essential because the visible location of a leak is not necessarily where the water first entered the structure.
Heavy Rainfall and Groundwater Pressure
Prolonged or intense rainfall can increase the amount of water in the surrounding ground. This creates hydrostatic pressure against basement walls and floors, forcing water through cracks, joints and weak points in the structure.
Failed Sump Pump
Type C cavity drain membrane systems often direct water towards a sump and pump. A mechanical fault, loss of power, blocked pipe or overwhelmed pump can allow water to accumulate within the basement.
Blocked or Damaged Drainage
Blocked channels, damaged drainage pipes or inadequate discharge routes can prevent water from being carried safely away from the property.
Failed Tanking or Waterproofing
Older tanking systems can fail because of movement, poor preparation, deterioration or increased water pressure. Water may then enter through cracks or weaknesses in the waterproof barrier.
Cracks and Construction Joints
Water can penetrate through cracks in concrete or masonry, wall-to-floor junctions, movement joints and openings created for pipes or other services.
External Defects
Defective gutters, downpipes, drainage, external ground levels and damaged building materials can direct additional water towards the basement structure.
Our surveyors inspect the affected area and consider the wider building and drainage conditions before recommending a repair.
Our Emergency Waterproofing Assessment
1. Discuss the Immediate Problem
When you contact us, tell us where the water is entering, when the problem started and whether there is active flooding, standing water or an installed pump system.
2. Inspect the Affected Area
Our waterproofing specialist will inspect the basement or cellar, assess the extent of the water ingress and look for signs that may indicate its source.
3. Identify the Likely Cause
We examine the walls, floor, joints, drainage, pump equipment and any existing waterproofing installation to determine why the system or structure is allowing water to enter.
4. Recommend Immediate and Long-Term Work
Where appropriate, we will explain any work needed to control the immediate problem and the permanent waterproofing measures required to reduce the risk of it happening again.
5. Provide a Clear Scope and Quotation
You will receive a clear recommendation describing the proposed repairs or replacement waterproofing system and the work involved.
6. Complete and Document the Installation
Our trained technicians install the agreed system using proven waterproofing products. Completed qualifying installations are inspected, documented and supported by our warranty.
Emergency Repairs and Long-Term Waterproofing Solutions
The right solution will depend on the source of the water, the construction of the building and whether an existing waterproofing system is already installed.
Recommended work may include:
Investigation of active water ingress
Repairs to failed waterproofing systems
Repair or replacement of cavity drain membranes
Drainage channel inspection and remedial work
Sump pump and associated system assessment
Crack, joint and penetration sealing
Cementitious tanking and barrier protection
Type C cavity drain membrane installation
Combined waterproofing systems for higher-risk properties
Removal and replacement of damaged internal finishes
Complete basement waterproofing and refurbishment
We install established waterproofing systems from manufacturers including Delta, KÖSTER and Sika.
Waterproofing Designed for the Property
Emergency attendance should not result in a rushed or unsuitable waterproofing specification. Once the immediate situation has been assessed, the permanent solution must be designed around the construction, condition and intended use of the property.
Depending on the findings, we may recommend:
Type A Barrier Protection
A waterproof barrier applied directly to the walls and floor to resist water passing through the basement structure.
Type C Cavity Drain Protection
A cavity drain membrane system that controls water entering through the structure and directs it towards a suitable drainage point or sump and pump.
Combined Protection
Where the property faces a higher risk of water ingress, more than one form of protection may be recommended to provide additional resilience.
Our surveyors design waterproofing recommendations in accordance with the principles of BS 8102 for the protection of below-ground structures against water ingress.
Why Choose Universal Basement Waterproofing?
Universal Basement Waterproofing has the technical knowledge and construction experience needed to investigate water ingress and provide a properly designed long-term solution.
More than 50 years of construction and waterproofing experience
Delta Membrane Systems approved installers
Experienced waterproofing surveyors and technicians
BS 8102-compliant waterproofing recommendations
Domestic and commercial waterproofing expertise
Solutions using Delta, KÖSTER and Sika systems
Detailed recommendations and clear scopes of work
Complete waterproofing and refurbishment available
Free 10-year installation and product warranty on qualifying work
Optional insurance-backed warranty protection
We investigate why the water is entering before recommending how the property should be repaired and protected.
Emergency Waterproofing for Homes and Commercial Properties
We investigate urgent water ingress affecting domestic and commercial properties, including:
Residential basements and cellars
Converted basement accommodation
Victorian and period properties
Commercial basements
Offices and retail premises
Plant and equipment rooms
Underground storage areas
Vaults and below-ground structures
New basement construction
Existing waterproofing installations
From isolated domestic leaks to complex commercial water ingress, our team can assess the problem and recommend the appropriate remedial work.
Emergency Waterproofing Across London and the South East
We provide urgent waterproofing assessments throughout London, Kent, Surrey, Essex, Sussex and surrounding areas.
Appointments and attendance times are subject to location and availability. Call our team as soon as possible so we can understand the situation and advise you about the earliest available assessment.
Call
020 3795 4900
or email
info@unbw.co.uk.
Emergency Waterproofing Frequently Asked Questions
Who should I call if my basement is flooding?
If there is an immediate danger to people, the building or its electrical supply, contact the emergency services or relevant utility provider first. For investigation of the water ingress and the waterproofing system, call Universal Basement Waterproofing on 020 3795 4900.
Do you provide 24-hour emergency waterproofing?
Availability depends on the time, location and nature of the problem. Call us to explain what is happening, and our team will advise you about the earliest available assessment. The page should not be taken as a guaranteed 24-hour call-out service.
Can you stop water entering immediately?
This depends on the cause and severity of the ingress. Some problems may be controlled with targeted remedial work, while others require drainage, pumping or a replacement waterproofing system. An inspection is needed before the correct action can be confirmed.
Why has my basement suddenly flooded?
Sudden flooding may be caused by heavy rainfall, rising groundwater, drainage failure, pump failure, cracks or defects in an existing waterproofing system. The visible water alone may not reveal the original entry point, so a professional inspection is important.
What should I do if electrics are near the water?
Do not enter the water or touch electrical equipment. Keep everyone away from the area and contact the emergency services or your electricity provider if there is an immediate electrical risk.
Can you repair a failed cellar tanking system?
Yes, depending on the condition and type of the existing system. We will inspect the installation, identify the likely failure and determine whether a localised repair, additional protection or complete replacement is required.
Can you repair or replace a failed sump pump?
We can assess the pump as part of the waterproofing and drainage system and recommend the appropriate remedial work. Do not dismantle or handle electrical pump equipment while the area is flooded.
Will the repair be guaranteed?
Qualifying commercial and domestic waterproofing installations receive our free 10-year installation and product warranty. The applicable guarantee will depend on the work and system installed and will be explained before the project begins.
How much does emergency waterproofing cost?
The cost depends on the source and extent of the water ingress, the damage caused and the remedial system required. After inspecting the property, we will explain the recommended work and provide a detailed quotation.
Speak to a Waterproofing Specialist Now
If water is entering your basement or cellar, contact us as soon as possible. Tell us what has happened, where the water is entering and whether there is active flooding or standing water.
Our team will discuss the situation and advise you about the earliest available professional assessment.
Urgent water ingress assessment
Identification of the likely cause
Immediate and long-term recommendations
Clear scope of work and quotation
Guaranteed qualifying waterproofing installations
Alternatively,
request an urgent waterproofing assessment online.
Email:
info@unbw.co.uk
Book Your Basement Survey Now
One of our waterproofing specialists will inspect your basement, discuss the most suitable waterproofing system and provide expert recommendations with no obligation.
Case Studies
Ready to Transform Your Basement?
Whether you’re planning a new basement or need to stop persistent damp and water ingress, our experienced surveyors can recommend the right waterproofing solution.
✔ Professional Survey
✔ Fully Guaranteed Work
✔ 50+ Years Experience
Frequently Asked Questions
In many cases, basement waterproofing alone does not require planning permission. However, basement construction, excavation, or significant structural alterations may require planning approval and Building Regulations compliance, particularly in certain London boroughs or conservation areas. We can advise you during your survey and help you understand any permissions your project may require.
The duration of a basement waterproofing project depends on the size and complexity of the work. Smaller waterproofing installations can often be completed within a few days, while larger basement construction or full structural waterproofing projects may take several weeks. Following your survey, we’ll provide a clear project schedule so you know exactly what to expect.
There is no single waterproofing system that is suitable for every property. The most effective solution depends on factors such as the construction of the building, ground conditions, water ingress risk, and how you intend to use the basement. Our experienced surveyors will assess your property and recommend the most appropriate BS8102-compliant waterproofing system, whether that’s a Type A (barrier protection), Type C (cavity drain membrane), or a combined system for maximum protection. We only install proven products from leading manufacturers, including Delta, KÖSTER, and Sika.
Yes. We install high-quality waterproofing systems from leading manufacturers such as Delta, KÖSTER, and Sika, following BS8102 standards for below-ground waterproofing. Our waterproofing systems are fully guaranteed, giving you confidence that your basement will remain dry and protected for years to come. We’ll explain the guarantees available during your survey.
We provide basement construction and structural waterproofing services throughout London, Kent, Surrey, Essex, Sussex, and the surrounding areas. If you’re unsure whether we cover your location, simply get in touch and our team will be happy to help.
Yes. We regularly waterproof existing basements, cellars, and vaults, whether they’re affected by damp, water ingress, or you’re planning to convert the space into a dry, usable room. Every property is different, so we carry out a professional survey to identify the cause of the problem before recommending the most suitable waterproofing solution. Our systems are designed to provide long-term protection while complying with BS8102 standards for below-ground structures.
With over 50 years of experience, Universal Basement Waterproofing has designed and installed waterproofing systems for properties across London and the South East. Our experienced surveyors design BS8102-compliant waterproofing solutions using trusted systems from Delta, KÖSTER, and Sika. From initial survey through to installation, we focus on delivering long-lasting, fully guaranteed waterproofing solutions tailored to every property.
We aim to arrange surveys as quickly as possible, subject to availability. During your survey, one of our experienced waterproofing specialists will assess your basement, discuss your requirements, identify any issues with damp or water ingress, and recommend the most suitable waterproofing solution. You’ll then receive a detailed, no-obligation quotation for the work required.