Introduction
Following official handover in December 2025, Tuath Housing and Cairn Homes announced the completion of Whitehaven, a landmark residential development in Northwood, Santry, Dublin 9. The scheme provides 255 new homes across five buildings, alongside communal indoor areas, landscaped gardens and multiple play spaces.
Designed and constructed to Passive House standards, Whitehaven represents one of Ireland’s largest Passive House residential developments delivered by an Approved Housing Body.
Working in collaboration with Platt and Reilly, Partel supplied a complete integrated airtightness system designed to support the project’s demanding Passive House performance targets. With extensive experience delivering high performance building envelope systems across Ireland and the UK, Platt and Reilly implemented a coordinated airtightness strategy focused on consistency, sequencing and long term durability.
Project Overview
Located approximately 1 km southeast of the Ballymun M50 interchange and 4 km south of Dublin Airport, Whitehaven establishes a new benchmark for sustainable residential construction in Ireland.
Each apartment incorporates high performance insulation, mechanical ventilation with heat recovery and energy efficient hot water heat pumps, supporting improved indoor comfort, lower operational energy demand and reduced carbon emissions.
The development is expected to deliver substantial long term operational energy savings across the lifecycle of the scheme while supporting improved comfort and indoor air quality for residents.
Completed over a construction period of just over two years, the development addresses growing demand for sustainable housing with close access to Dublin City University, schools and local community infrastructure.
The project was developed by Tuath and Cairn Homes in partnership with Fingal County Council, with funding support provided through the Department of Housing, Local Government and Heritage under the Cost Rental Equity Loan (CREL) scheme alongside private finance through the Housing Finance Agency (HFA).
Airtightness and Passive House Standards
Passive House buildings require extremely high levels of airtightness to achieve energy efficiency, thermal comfort and long term building durability. The standard mandates a maximum air leakage rate of 0.6 air changes per hour at 50 Pascals.
Achieving this level of performance requires a continuous airtight layer throughout the building envelope, supported by correct sequencing, coordinated detailing and careful management of interfaces and penetrations.
In addition to specifying high performance airtightness materials, including Passive House certified components, successful delivery also depends on early engagement, installer education and ongoing technical guidance throughout construction.
Delivering airtightness at scale within apartment buildings introduces several additional challenges:
Multiple Junction Types
Apartment buildings contain a significantly higher number and variety of junctions compared to individual dwellings. Each junction introduces potential air leakage paths, making continuity of the airtight layer a critical design consideration.
Repetition Across Units
Repeated apartment layouts can support standardisation of successful details and installation methods. However, any design issue or installation inconsistency can also be replicated across the entire development. This increases the importance of quality assurance, technical guidance and consistent workmanship.
Interfaces Between Structural Elements
Interfaces between windows, floors, service penetrations and structural elements are often the most vulnerable locations for air leakage. Maintaining airtight continuity across these interfaces requires close coordination between multiple trades and accurate installation sequencing.
Product and System Selection
A robust airtightness strategy requires careful consideration of both product specification and installation methodology. Key considerations on projects targeting Passive House performance include:
- Minimum membrane overlap requirements
- Correct priming of porous substrates
- Immediate repair of membrane damage
- Proper activation of pressure sensitive tapes
- Protection of airtight layers during follow on trades
Partel worked closely with Platt and Reilly to develop a coordinated airtightness approach based on compatible products, repeatable detailing and long term performance.
Partel Product Specification
IZOPERM PLUS Airtight Membrane
IZOPERM PLUS was used as the primary internal airtight membrane throughout the development, providing a reliable airtight layer and vapour control solution compatible with conventional construction systems.
The membrane is Passive House Institute certified as a phA advanced component and features:
- Air permeance below 0.01 m³/(m²h)
- Sd value of 5 m
- W1 water resistance classification
Its durability and installation flexibility made it well suited to the demands of large scale apartment construction.
EXOPERM MONO SA 250 Breather Membrane
EXOPERM MONO SA 250 was installed to the external wall assemblies as a self adhered airtight and vapour permeable breather membrane based on monolithic membrane technology.
The membrane was selected for its ability to provide:
- Airtightness
- Vapour permeability
- External weather protection
- Durable adhesion across multiple substrates
Its integrated self adhesive layer supported efficient installation while integrated reinforcement enhanced robustness during construction.
EXOPERM MONO SA 250 was applied across substrates including timber, CLT elements, OSB, steel, concrete and masonry.
With an Sd value of 0.26 m, the membrane supports high vapour permeability and effective moisture management within the wall assembly.
CONEXO MULTISEAL Tape
CONEXO MULTISEAL Tape was used at membrane junctions, window corners and interface connections throughout the project.
Suitable for use with IZOPERM PLUS as part of a complete airtightness system, the tape provides permanent airtight and windtight sealing of membrane overlaps and junctions.
The tape offers:
- Solvent free formulation
- Airtightness performance to DIN 4108-11
- Strong ageing resistance
- Low VOC content
VARA SEAL Tape
VARA SEAL Tape was applied at floor expansion joints, concrete pillars and threshold interfaces where durable airtight continuity was critical.
The tape features a humidity variable Sd value alongside a high performance moisture resistant acrylic adhesive designed for demanding construction interfaces.
Its application helped maintain continuity of the airtight layer from basement to upper floor levels.
ACRAPRIME
ACRAPRIME primer, supplied in both spray and liquid formats, was used to prepare porous substrates including concrete, plaster, masonry, timber and fibreboard surfaces prior to tape installation.
Used in combination with VARA SEAL and CONEXO MULTISEAL tapes, the primer provided improved adhesion reliability and long term durability of airtight connections throughout the project.
Benchmark Inspection
As part of the project delivery process, a benchmark inspection was carried out during the construction phase in February 2025 with representatives from Partel, Cairn Homes, Platt and Reilly and MosArt, who were overseeing Passive House consultancy and certification for the development.
The inspection formed part of the project’s onsite quality assurance process, assessing installation quality, sequencing and detailing to ensure the development remained on track to achieve its targeted Passive House airtightness performance.
The benchmark review validated that previous technical guidance and installation procedures had been implemented correctly, including:
- Correct substrate preparation and priming
- Consistent membrane overlaps and tape application
- Accurate detailing at penetrations and critical junctions
Importantly, the inspection also demonstrated the effectiveness of repeatable installation methodologies across multiple apartment units.
The combination of standardised detailing, coordinated sequencing and ongoing technical support helped reduce installation variability and improve quality assurance throughout the project.
Outcome
Through close collaboration between Partel, Platt and Reilly and the wider project team, Whitehaven successfully implemented a coordinated airtightness strategy aligned with Passive House performance requirements.
The project demonstrates how repeatable detailing, installer training and integrated system specification can support the successful delivery of large scale Passive House residential developments.
Executives from Tuath Housing and Cairn Homes described Whitehaven as a milestone project for collaborative sustainable housing delivery and a model for future energy efficient residential construction across Ireland.
Martin Loughran, Chief Commercial Officer at Tuath Housing, stated:
“This project showcases what can be achieved when innovation, collaboration and environmental responsibility come together.”
“By providing homes that set a new benchmark for energy efficiency, comfort and affordability, we are not just building for today, we are building a more sustainable future for our residents and communities.”
References
https://irishconstruction.com/a-milestone-for-sustainability/
https://mosartgroup.com/projects/whitehaven/
https://www.pleanala.ie/en-ie/case/313317
https://www.irishtimes.com/business/2023/04/03/developer-cosgrave-gets-green-light-to-build-255-apartments-in-santry/
https://constructionnews.ie/cairn-passive-house-project-largest-in-europe/
https://www.buildinginfo.com/project/e59m-whitehaven-shd-in-co-dublin/
