Airtightness
A clear airtightness strategy must remain continuous across every junction. Careful workmanship, protection of completed layers & close coordination between trades are essential.
High-Performance Residential Construction
Passivhaus Builder in Somerset
Benjamin Henry delivers Passivhaus & high-performance homes across Somerset & the South West, combining precise construction, traditional craftsmanship & modern building science.
From bespoke new homes to deep-energy renovation, our team understands that exceptional building performance depends on every part of the project working together — structure, insulation, airtightness, windows, ventilation, heating, electrical systems & renewable technology.
The Building Fabric
Building High-Performance Homes Properly
Passivhaus is not simply a matter of adding more insulation. A high-performance home is only as good as its weakest detail.
Low energy demand, stable indoor temperatures & excellent air quality depend on continuous insulation, airtightness, thermal-bridge control, high-performance windows, controlled ventilation, careful detailing & coordinated services.
Benjamin Henry brings together construction experience, specialist trades & building-performance knowledge to translate a considered design accurately into the finished building. Testing & sequencing between trades are treated as part of construction quality, not checks left until the end.
What We Deliver
High-Performance Construction From Fabric to Services
Thermal Bridge Control
Junctions around foundations, structure, roofs & openings are built carefully so localised heat loss does not undermine the wider envelope.
Insulation Continuity
Insulation performs as a complete layer. Gaps, compression & poorly coordinated interfaces are avoided through considered sequencing & inspection.
High-Performance Windows & Doors
Specification is only part of the answer. Positioning, support, sealing & integration with the insulation and airtight layers determine how each opening performs.
MVHR
Mechanical Ventilation with Heat Recovery provides controlled fresh air while retaining much of the warmth from outgoing air. Its design, duct routes & commissioning need early coordination.
Heating Systems
Low-energy homes may suit heat pumps, underfloor heating or other carefully selected systems. The right solution depends on the design, heat demand & intended use.
Solar & Battery Storage
Renewable generation & battery storage can be integrated where appropriate, with roof, electrical & plant requirements considered within the wider programme.
Electrical & Smart Home Systems
Our wider in-house capability supports coordinated electrical installations, architectural lighting, EV charging & smart-home technology without treating services as an afterthought.
Not every technology is appropriate for every home. The objective is a coherent strategy in which the fabric & services are selected, detailed & coordinated for the individual project.
Why Benjamin Henry
Craftsmanship guided by building science
Whole-Building Understanding
We understand how structure, fabric, finishes & services affect one another, and why decisions cannot be made in isolation.
Integrated Trades
Construction, joinery & electrical capability within the wider business supports clearer sequencing and fewer gaps between packages.
Traditional Craftsmanship
Modern performance still relies on patient, accurate workmanship. The same care applied to visible finishes is required in every concealed junction.
Modern Building Science
Practical site knowledge is combined with the principles of airtightness, thermal continuity, moisture control & measured quality assurance.
Complex Residential Projects
Our work is centred on substantial, architect-designed homes, conversions & renovations requiring close collaboration across the project team.
Heritage & Performance
Older buildings require a different response. Breathability, moisture movement & historic fabric must inform any improvement strategy.
New Build
Passivhaus & High-Performance New Homes
We deliver architect-designed new homes built around Passivhaus or comparable high-performance principles. Construction planning considers foundations & thermal continuity, airtightness, structural junctions, window installation, testing, services, renewables, finishes & quality control as one coordinated programme.
Explore our bespoke new homesExisting Buildings
High-Performance Retrofit & EnerPHit
Retrofit is fundamentally different from new construction. Existing fabric, breathability, moisture movement, thermal bridges, windows, ventilation, modern services & heritage constraints must be understood together. Passivhaus-style retrofit is not automatically suitable for every historic property; the correct approach depends on the building.
Explore our heritage & listed-building workRelevant Experience
High-Performance Projects
Somerset · EnerPHit Retrofit
The Rectory
A large Victorian property reconfigured & renovated towards the EnerPHit standard, with insulation upgrades, triple-glazed Passivhaus-certified windows, airtightness detailing & underfloor heating.
View Project →Coming shortly…
New-Build Passivhaus
Mill Bank
Benjamin Henry’s first full new-build Passivhaus project, bringing together careful envelope construction, airtightness detailing & coordinated building services.
Read the Passivhaus article →Integrated Building Services
Performance depends on coordination
Ventilation, heating, electrical infrastructure & renewables all pass through or connect with the building fabric. Early coordination protects the airtight layer, creates practical service routes & helps systems work as intended.
Benjamin Henry’s wider electrical capability covers architectural lighting, smart-home technology, solar, battery storage & EV charging where those systems suit the project.
Explore Benjamin Henry Electrics
Our Approach
From Design to Completion
Early Project Review
Understanding the brief, design, performance targets & the particular constraints of the site and building.
Pre-Construction Coordination
Reviewing construction details, sequencing, services & the interfaces where different trades and systems meet.
Building Fabric
Delivering the structure, insulation, airtight layer & critical junctions with disciplined workmanship on site.
Services Integration
Coordinating ventilation, heating, electrical & renewable systems with the fabric and interior programme.
Testing & Quality Control
Supporting appropriate inspections, testing & quality checks as work progresses, while details remain accessible.
Completion
Finishing the home to Benjamin Henry’s usual craftsmanship standards while protecting the performance strategy established during construction.
Experience & Accreditation
Evidence behind the detail
Certified Passive House Tradesperson
Benjamin Cavaghan is listed in the Passivhaus Institute directory as a Certified Passive House Tradesperson, record H10140.
View directory record
Established Residential Contractor
Federation of Master Builders membership, substantial architect-led residential work & LABC South West 2025 recognition for Church Barn support a wider record of construction quality.
Integrated Capability
In-house joinery & electrical capability, alongside experienced construction trades & specialist consultants, help the project team coordinate critical interfaces.
Frequently Asked Questions
Passivhaus, clearly explained
For a broader introduction, read our Passivhaus guide.
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Planning a High-Performance Home?
If you are planning a Passivhaus, low-energy new build or substantial high-performance renovation in Somerset or the South West, speak to the Benjamin Henry team about your project.