TECHNICAL ARTICLES
With a substantial share of Istanbul’s building stock constructed in or before 2000, projects on narrow and access-constrained sites are expected to become increasingly common.
These conditions require foundation and basement wall waterproofing to be approached differently from conventional applications.
Why Does Waterproofing Require a Different Approach on Adjoining Sites?
In detached developments, waterproofing can usually be applied to the external face of reinforced concrete walls before backfilling. On adjoining sites, however, property boundaries, neighbouring buildings, and earth-retaining systems may restrict or completely eliminate external access.
In such cases, waterproofing must be planned before reinforced concrete construction begins. Turkey’s Regulation on Waterproofing in Buildings also highlights the importance of suitable application surfaces, continuity between foundations and basement walls, and protection against hydrostatic pressure where structures are located below groundwater level.
The challenge on restricted sites is therefore not only to save space, but also to maintain continuous and reliable waterproofing in areas where future access is limited.
Why Are Single-Sided Wall Applications Important?
Single-sided wall systems provide an effective solution where external access will not be possible after construction.
The waterproofing layer is installed before the concrete is poured, allowing the reinforced concrete wall to be formed directly against the membrane. Pre-applied membranes that bond to fresh concrete create a continuous connection between the waterproofing layer and the structure, helping restrict lateral water migration in the event of localised damage.
This is particularly important in basement areas where future intervention is difficult. Limiting water and moisture exposure also helps reduce the risk of reinforcement corrosion and supports long-term structural durability.
Bonus Membran Proof for Restricted Sites
Bonus Membran Proof is an elastomeric SBS-modified waterproofing membrane reinforced with polyester felt and developed for foundation and single-sided wall applications.
Bonus Membran Proof EP300 V bonds directly to freshly poured concrete, creating strong integration between the membrane and the concrete surface. This fully bonded structure helps limit water migration between the waterproofing layer and the structure.
Its single-layer application eliminates the need for primer, protective concrete, and geotextile felt, helping simplify installation and reduce labour on space-constrained sites. Self-adhesive overlap sections also support faster application and continuous waterproofing performance.
The system can be installed directly in front of the earth-retaining structure, reducing the need for additional external working space and allowing foundation and basement wall waterproofing to be completed within the available building footprint.
The Right Detailing for Long-Term Performance
In urban transformation projects, every square metre matters. However, efficient use of space should not compromise waterproofing continuity, particularly at foundation level.
Because foundations and basement walls are among the most difficult areas to access after construction, waterproofing should be considered from the design stage rather than treated as a later application.
For narrow and adjoining urban sites, Bonus Membran Proof provides a high-performance solution that supports efficient use of space, installation efficiency, and long-term structural protection
Single-Sided Wall Waterproofing Solutions for Restricted Urban Sites
As urban transformation accelerates across Istanbul, construction projects are increasingly shaped by the physical constraints of the existing urban fabric. Small plots, adjoining buildings, neighbouring structures, and excavations close to property boundaries can significantly limit available working space.With a substantial share of Istanbul’s building stock constructed in or before 2000, projects on narrow and access-constrained sites are expected to become increasingly common.
These conditions require foundation and basement wall waterproofing to be approached differently from conventional applications.
Why Does Waterproofing Require a Different Approach on Adjoining Sites?
In detached developments, waterproofing can usually be applied to the external face of reinforced concrete walls before backfilling. On adjoining sites, however, property boundaries, neighbouring buildings, and earth-retaining systems may restrict or completely eliminate external access.
In such cases, waterproofing must be planned before reinforced concrete construction begins. Turkey’s Regulation on Waterproofing in Buildings also highlights the importance of suitable application surfaces, continuity between foundations and basement walls, and protection against hydrostatic pressure where structures are located below groundwater level.
The challenge on restricted sites is therefore not only to save space, but also to maintain continuous and reliable waterproofing in areas where future access is limited.
Why Are Single-Sided Wall Applications Important?
Single-sided wall systems provide an effective solution where external access will not be possible after construction.
The waterproofing layer is installed before the concrete is poured, allowing the reinforced concrete wall to be formed directly against the membrane. Pre-applied membranes that bond to fresh concrete create a continuous connection between the waterproofing layer and the structure, helping restrict lateral water migration in the event of localised damage.
This is particularly important in basement areas where future intervention is difficult. Limiting water and moisture exposure also helps reduce the risk of reinforcement corrosion and supports long-term structural durability.
Bonus Membran Proof for Restricted Sites
Bonus Membran Proof is an elastomeric SBS-modified waterproofing membrane reinforced with polyester felt and developed for foundation and single-sided wall applications.
Bonus Membran Proof EP300 V bonds directly to freshly poured concrete, creating strong integration between the membrane and the concrete surface. This fully bonded structure helps limit water migration between the waterproofing layer and the structure.
Its single-layer application eliminates the need for primer, protective concrete, and geotextile felt, helping simplify installation and reduce labour on space-constrained sites. Self-adhesive overlap sections also support faster application and continuous waterproofing performance.
The system can be installed directly in front of the earth-retaining structure, reducing the need for additional external working space and allowing foundation and basement wall waterproofing to be completed within the available building footprint.
The Right Detailing for Long-Term Performance
In urban transformation projects, every square metre matters. However, efficient use of space should not compromise waterproofing continuity, particularly at foundation level.
Because foundations and basement walls are among the most difficult areas to access after construction, waterproofing should be considered from the design stage rather than treated as a later application.
For narrow and adjoining urban sites, Bonus Membran Proof provides a high-performance solution that supports efficient use of space, installation efficiency, and long-term structural protection