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RJ Evans Flat Roofing Limited provides mastic asphalt balcony waterproofing and repair to prevent water ingress, restore damaged asphalt surfaces, and protect balconies and terraces from moisture deterioration. Asphalt balcony waterproofing is the process of applying mastic asphalt, a specialist waterproofing material, to the substrate of a balcony or terrace to create a seamless and durable waterproof barrier. The mastic asphalt prevents water from penetrating the balcony structure and protects the substrate from leaks, moisture damage, frost exposure, and continued deterioration. It also creates a smooth, even, and hard-wearing surface that can remain exposed or receive a compatible decorative finish.
Asphalt balcony repair is the process of repairing damage to a balcony or terrace surface that has been waterproofed with mastic asphalt. The repair process identifies and addresses cracks, holes, surface wear, and other forms of deterioration that have weakened the asphalt surface or interrupted its waterproofing function. Depending on the condition of the balcony, the damaged areas may be cleaned, prepared, patched, sealed, or resurfaced. Mastic asphalt balcony repairs restore the continuity of the waterproof barrier, prevent further water penetration, and help return the balcony to a watertight, safe, and functional condition. Repairing deterioration promptly protects the underlying substrate, preserves the surrounding asphalt, and extends the service life of the existing waterproofing system.
Mastic asphalt balcony waterproofing is the right solution when a balcony or terrace requires a continuous waterproof barrier and the existing structure remains suitable for preparation, repair, and installation. The system can be used on new balcony construction or to restore an existing balcony where water ingress, surface deterioration, or failed waterproofing is affecting performance.
Mastic asphalt should not be selected solely because the balcony is leaking. The condition of the substrate, drainage falls, outlets, perimeter details, thresholds, movement joints, previous repairs, and intended surface finish must first be assessed. This determines whether the balcony can receive mastic asphalt directly, requires corrective work before waterproofing, or needs a different repair or replacement strategy.
Mastic asphalt balcony waterproofing is appropriate in the following situations:
Stable balcony substrate → mastic asphalt can form a durable waterproofing layer.
The concrete deck, screed, timber deck, or other specified substrate must remain stable enough to support the waterproofing system. Minor surface deterioration may be repairable, but structural cracking, excessive movement, severe spalling, or unstable sections must be investigated and corrected before mastic asphalt is installed.
Failed or incomplete waterproofing → mastic asphalt can restore waterproofing continuity.
Mastic asphalt may be used where the existing balcony allows water to penetrate through cracks, joints, worn surfaces, or failed waterproofing details. Once the substrate and adjoining details have been prepared correctly, the asphalt creates a continuous barrier that protects the balcony structure and the occupied or enclosed areas below.
Effective balcony drainage → standing water and moisture pressure are reduced.
The balcony must direct water towards suitable outlets, gutters, or drainage channels. Where the existing surface is uneven or contains low points, corrective screeding or levelling may be required before waterproofing. Mastic asphalt can form part of a balcony build-up with properly designed falls, but the waterproofing layer should not be expected to compensate for unresolved drainage defects.
Repairable balcony defects → the surface can be stabilised before mastic asphalt is applied.
Cracks, holes, damaged edges, isolated areas of spalling, failed joints, and deteriorated sections do not always require complete balcony reconstruction. Where the damage is limited and the underlying structure remains viable, affected areas can be repaired and prepared before the new waterproofing system is installed.
Waterproofable balcony interfaces → the mastic asphalt system can maintain continuity at vulnerable details.
Balcony waterproofing must remain continuous around walls, door thresholds, outlets, balustrade supports, service penetrations, kerbs, and adjoining roof or façade elements. These interfaces must provide sufficient space and suitable surfaces for correctly formed waterproofing details. Defective or inaccessible junctions must be redesigned or repaired before installation.
Compatible use and finish requirements → the balcony can remain functional after waterproofing.
The proposed build-up must account for pedestrian use, maintenance access, slip resistance, finished levels, threshold heights, and any decorative covering. Depending on the specification, the mastic asphalt may remain as the exposed wearing surface or receive compatible promenade tiles, paving, protective coatings, or another approved finish.
A balcony or terrace may remain suitable for mastic asphalt waterproofing even when defects are present. However, any condition that could interrupt waterproofing continuity, prevent adhesion, restrict drainage, or allow continued structural deterioration must be corrected before the full system is installed.
Repairs may be required in the following situations:
Localised asphalt deterioration → damaged material must be cut out and reinstated.
Cracks, splits, blisters, worn areas, and surface breakdown can interrupt the waterproofing layer and allow water to reach the substrate. Where deterioration is confined, the affected asphalt can be removed back to stable material and repaired with a compatible mastic asphalt system. Widespread deterioration may require complete resurfacing rather than isolated patching.
Defective balcony substrate → structural and surface repairs must be completed first.
Loose concrete, damaged screed, exposed reinforcement, open cracks, and unstable deck areas cannot be concealed beneath a new waterproofing layer. Unsound material must be removed, the cause of the deterioration investigated, and the substrate repaired before mastic asphalt is applied.
Inadequate perimeter details → waterproofing terminations must be corrected.
Water can enter where the balcony waterproofing meets walls, door openings, kerbs, parapets, or exposed edges. Damaged upstands, insufficient termination heights, open joints, and poorly formed thresholds must be corrected so the mastic asphalt can terminate securely and maintain a continuous barrier.
Restricted or misdirected drainage → water movement must be corrected before waterproofing.
Blocked outlets, deteriorated gutters, inadequate falls, and localised low points can cause water to remain on the balcony. These defects should be corrected through cleaning, outlet repair, localised levelling, or formation of suitable falls before the waterproofing system is completed.
Vulnerable moving or interrupted details → compatible detailing must be installed.
Movement joints, balustrade supports, pipes, drainage components, and other penetrations interrupt the main balcony surface. Failed seals or rigid repairs around these locations must be replaced with details capable of maintaining waterproofing continuity while accommodating the expected movement of the adjoining components.
Unstable existing materials → unsuitable layers must be removed or isolated.
Previous repair compounds, paints, adhesives, tiles, coatings, and patch materials may prevent the new system from bonding or behaving consistently. Loose or incompatible materials must be removed, and retained surfaces must be tested and prepared in accordance with the selected waterproofing specification.
All necessary repairs must be completed before the new mastic asphalt waterproofing layer is installed. The system should protect a stable, correctly drained, and properly prepared balcony rather than cover unresolved defects that could continue to cause water ingress or premature waterproofing failure.
Mastic asphalt balcony waterproofing is not appropriate where the balcony structure, substrate, drainage arrangement, or construction details cannot support a reliable waterproofing system. In these situations, structural repair, balcony reconstruction, substrate replacement, or an alternative waterproofing specification may be required.
Mastic asphalt balcony waterproofing may not be appropriate in the following situations:
Structural instability → waterproofing should not proceed until the balcony is stabilised.
Mastic asphalt cannot correct structural movement, deflection, failed supports, or unstable balcony connections. Where structural defects are suspected, the balcony must be assessed and repaired before any surface waterproofing system is considered.
Extensive substrate deterioration → broader repair or reconstruction is required.
Where deterioration affects large areas of concrete, screed, timber, or another supporting substrate, isolated patching will not provide a dependable base for waterproofing. The damaged build-up may need to be removed and reconstructed before a new system is installed.
Unrelated or concealed water source → the source of ingress must be identified first.
Moisture may enter through façades, door assemblies, cavity details, service penetrations, adjoining roofs, or internal plumbing rather than through the balcony surface. Applying mastic asphalt without identifying the source can leave the original leak unresolved and may conceal continued deterioration.
Unresolvable drainage or level constraints → the proposed waterproofing build-up must be reconsidered.
A balcony system must direct water to suitable outlets while maintaining acceptable levels at doors, thresholds, edges, and adjoining finishes. Where the available construction depth cannot accommodate the required waterproofing, drainage, and surface finish, an alternative design may be necessary.
Unsuitable or contaminated substrate → reliable installation cannot be achieved.
Loose material, persistent contamination, incompatible coatings, trapped moisture, or inaccessible areas may prevent proper preparation. Mastic asphalt should not be installed until the substrate can provide a stable and suitable base for the complete waterproofing specification.
Incompatible balcony design requirements → a different system or construction build-up may be needed.
The waterproofing system must be compatible with available threshold heights, structural loading, pedestrian use, accessibility requirements, drainage components, and the proposed finish. Where these requirements cannot be reconciled, the balcony design should be revised before installation proceeds.
Mastic asphalt is used for balcony and terrace waterproofing because it combines waterproofing continuity with a durable surface capable of supporting regular pedestrian use. When installed over a suitable substrate and detailed correctly at outlets, perimeters, thresholds, and penetrations, it protects the balcony structure from water penetration and continued moisture-related deterioration.
The principal benefits of mastic asphalt balcony waterproofing include:
Continuous mastic asphalt layer → joints and vulnerable surface areas remain protected.
Mastic asphalt is applied to form a continuous waterproofing layer across the balcony or terrace. Correct detailing at perimeters, outlets, penetrations, and adjoining construction prevents isolated weak points from interrupting the main waterproof barrier.
Durable waterproofing surface → the balcony can withstand regular use and environmental exposure.
A correctly specified mastic asphalt system provides a robust surface for balconies, terraces, walkways, and other pedestrian areas. The completed build-up can resist normal foot traffic while continuing to protect the substrate from rainfall, frost, and repeated wetting.
Repairable waterproofing material → isolated defects can be reinstated locally.
Where damage is confined to a specific area, the affected mastic asphalt can usually be cut out to stable material and remade using a compatible repair specification. This allows waterproofing continuity to be restored without automatically removing unaffected areas of the balcony system.
Correctly formed balcony falls → water is directed towards outlets and drainage channels.
Mastic asphalt waterproofing can be combined with a suitable screed or levelling build-up where falls need to be formed or corrected. This helps prevent low points and supports controlled water movement across the completed balcony surface.
Compatible balcony finishes → waterproofing and appearance can be addressed within one system design.
Depending on the specification, mastic asphalt may remain exposed or be covered with promenade tiles, paving, a compatible coating, or another approved finish. The selected finish must be compatible with the waterproofing layer, drainage design, intended use, and available construction depth.
Reduced water penetration → moisture-related deterioration of the balcony substrate is controlled.
By preventing water from passing through the balcony surface, mastic asphalt helps protect concrete, screed, reinforcement, timber, and adjoining building components from continued moisture exposure. This supports the long-term watertightness and serviceability of the balcony or terrace.
RJ Evans Flat Roofing Limited selects mastic asphalt balcony waterproofing according to the condition of the substrate, the cause of water ingress, drainage performance, perimeter detailing, intended use, and required surface finish. Where the balcony remains structurally viable and can be repaired and prepared correctly, mastic asphalt provides a continuous, durable, and maintainable waterproofing solution. Where the substrate or balcony design cannot support the system, corrective construction work or an alternative waterproofing approach is specified instead.
Mastic asphalt stands as a premier choice for balcony waterproofing, renowned for its exceptional durability, waterproofing capabilities, and environmental friendliness. Mastic asphalt, often hailed as “The King of Waterproofing” offers a blend of long-term protection, cost-effectiveness, and aesthetic versatility for any balcony. The following overview highlights the numerous advantages of choosing mastic asphalt for balcony waterproofing, underscoring its significance in enhancing the longevity, functionality, and appearance of outdoor living spaces.
Mastic asphalt's superior waterproofing capabilities ensure that it creates a seamless and impervious barrier against water penetration. This characteristic is crucial for balconies, which are exposed to the elements, as it prevents water from seeping into the building structure, thereby avoiding the potential for moisture-related damage such as concrete spalling and corrosion of reinforcement bars.
As the only carbon zero rated waterproofing system in the construction industry, mastic asphalt stands out for its minimal environmental impact. This rating signifies that its production and application process has a net-zero carbon footprint, making it an ideal choice for projects aiming for sustainability and eco-friendliness.
Mastic asphalt's robust composition ensures a long service life, often exceeding 50 years with proper care and maintenance. This durability is due to its resistance to weathering, temperature fluctuations, and mechanical wear, which are critical for outdoor applications like balconies where exposure to the elements is constant.
The initial investment in mastic asphalt for balcony waterproofing pays off in the long term through its durability and low maintenance needs. Unlike other materials that may require frequent repairs or replacements, mastic asphalt's longevity and ease of repair work make it a financially viable option, offering significant savings over the lifespan of the balcony.
In the event of damage, mastic asphalt can be easily repaired by a skilled asphalter who can cut out the damaged section and seamlessly replace it. This ease of repair minimizes downtime and reduces the cost and complexity associated with maintenance, ensuring the balcony remains in top condition with minimal effort.
Beyond its practical benefits, mastic asphalt allows for aesthetic customisation through various finishing options. Balconies can be enhanced with promenade tiles for a decorative touch or coated with solar reflective paint to achieve an attractive and protective light grey finish. These options offer flexibility in design while ensuring the balcony's surface remains protected and visually appealing.
The application of solar reflective paint over mastic asphalt not only enhances the balcony's appearance but also provides a protective layer against UV radiation. This is particularly beneficial for southward-facing balconies, which are more susceptible to sun damage. The reflective properties of the paint extend the life of the balcony by preventing the asphalt from degrading under intense sunlight.
The widespread use of mastic asphalt for balcony waterproofing in densely populated cities like London demonstrates its reliability and effectiveness across various architectural styles and building types. Its popularity in urban settings is a testament to its versatility, durability, and the trust placed in it by construction professionals and property owners alike.
Mastic asphalt balcony repair is a specialised process aimed at restoring the integrity and waterproofing capabilities of balconies that have been damaged or have deteriorated over time. This repair method involves the application of mastic asphalt, a highly durable and waterproof material, to the surface of the balcony to seal cracks, level uneven areas, and create a seamless protective layer. The process typically starts with a thorough assessment of the balcony to identify all areas of concern, followed by surface preparation, which may include cleaning, removing loose materials, and repairing significant structural damage.
Once the surface is prepared, a new layer of mastic asphalt is applied, often by skilled professionals who ensure that the material is evenly spread and fully adheres to the underlying surface. Mastic asphalt not only re-establishes the balcony’s waterproof barrier but also enhances its appearance and usability. Given its excellent adherence properties and flexibility, mastic asphalt can accommodate slight movements of the building without cracking, making it an ideal solution for balcony repair. Additionally, this type of repair can extend the lifespan of the balcony, prevent future water ingress, and protect the building’s structure from further damage. The effectiveness of mastic asphalt in balcony repair lies in its ability to provide a durable, long-lasting, and aesthetically pleasing surface that withstands the rigours of weather and usage.
A well-maintained balcony not only adds value and aesthetic appeal to your property but also provides a safe, outdoor space for relaxation and entertainment. However, the waterproofing integrity of your balcony is crucial in preserving its condition and functionality. Failure in the waterproofing system can lead to significant damage, necessitating costly repairs. Recognising the early signs of such failures can be instrumental in taking timely action to mitigate further damage and ensure the safety and longevity of your balcony. Here are the key indicators of balcony waterproofing failure:
A leaking balcony clearly signals a failure in the waterproofing barrier, most noticeable after rain when water finds its way through cracks and gaps, compromising the structure below. This issue goes beyond structural damage; it creates an environment conducive to mould and mildew growth, posing health risks and potentially ruining interior finishes and furnishings. The persistent dampness can weaken the concrete or wood, accelerating the degradation process and necessitating urgent repairs to prevent further damage.
Water that remains on a balcony surface well after a rainfall event is a telltale sign of inadequate drainage or compromised waterproofing. Such standing water indicates that the designed slopes or drainage systems are not functioning correctly, possibly blocked or insufficient, leading to water accumulation. This stagnation not only poses a slip hazard but also serves as a catalyst for further waterproofing breaches, progressively damaging the balcony structure and encouraging the development of efflorescence and algae.
Visible splits and cracks on a balcony act as direct channels for moisture entry, undermining the integrity of the waterproof membrane. Continuous exposure to water through these breaches not only facilitates the ingress of moisture into the structural and interior spaces but also weakens the balcony's overall structural integrity by eroding the construction materials, potentially leading to significant repair needs.
The presence of moss and lichen on the balcony surface signals constant moisture presence and insufficient waterproofing. These organisms deteriorate the balcony's surface over time, allowing more moisture to penetrate and further compromise the structure. Their growth can etch into surfaces, making them slippery and unsafe while accelerating the wear and tear on the waterproofing layer.
Blows, or blistering, on the balcony surface are indicative of trapped moisture or air beneath the waterproofing membrane, a definite sign of membrane failure. The trapped moisture not only signals existing leaks but also foretells the rapid deterioration of the structure beneath, as the expanding moisture can cause delamination and further separation of the waterproofing layers from the substrate.
When asphalt begins to pull away from coping stones, it highlights a failure in the adhesive bond integral to the waterproofing system. This detachment forms gaps that allow water to penetrate the balcony's edges, undermining the comprehensive seal intended to keep water out and compromising the structural integrity of the balcony edge and the building façade.
A discoloured, worn-out appearance on the balcony's surface often points to the aging and deterioration of the waterproofing material. Beyond aesthetics, this signals a weakening in the material's ability to repel water, making the balcony susceptible to leaks and water damage, and indicating the need for reapplication or repair of the waterproofing system.
Slumping or an uneven surface on the balcony suggests underlying structural or material degradation, exacerbated by failed waterproofing. This unevenness disrupts proper drainage, pooling water in low areas, and placing additional stress on the already compromised waterproofing system, further endangering the balcony's structural components.
Addressing these signs of waterproofing failure with a thorough assessment and professional repair is crucial for maintaining the safety, functionality, and longevity of the balcony. Delaying repairs can lead to more extensive and expensive damage, highlighting the importance of regular inspections and maintenance to safeguard the integrity of outdoor living spaces.
At RJ Evans we have our own Asphalt Mixer this means a flame free laying of the mastic asphalt. Better consistency in the asphalt mixture meaning a more efficient installation process with a better overall finish.
• Vastly experienced asphalt team. We have operatives with more than 40 years’ experience.
• We provide a range of FREE quotations and solutions for all projects.
• Insurance Backed Guarantees.
• Excellent Customer Support throughout project.
• Rated 5 out of 5 from our previous customers.
If you need a quote or further details about our asphalt balcony waterproofing and repair services, we’re here to help. Simply fill out our contact form or give us a call on 01277 375 511, and one of our knowledgeable team members will be happy to assist you. Don’t hesitate to reach out, we’re ready to help.
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