Twin Wall (Passive) System

Stylish Design Features
High levels of comfort
90% less energy
If you’re considering a PASSIVE build

Take a look at our Twin Wall System

For many, the dream of designing and building their own Passive House is the culmination of years of planning and exciting thinking. With MBC Timber Frame, the reality of a Passive House, bringing together all of the design features and high levels of comfort associated with this approach, is now not only a possibility but an incredibly cost effective possibility.

A Passive House is a precisely engineered and detailed structure that is highly insulated, cold bridge free and requires 90% less energy for space heating or cooling. Building a Passive House does not cost extra in the long term as there is no need to install a complex heating system. Finances saved are invested into essential Passive House Elements, the cost of which is quickly recouped within a few years of building completion

A Passive House is fitted with a variety of non structural high performance essential elements, which include:

  • Triple gazed windows
  • Thermal Insulation barrier
  • Airtight membrane and tapes
  • Mechanical Ventilation and Heat Recovery (MVHR)



Passive House Components


The MBC Passive Foundation

MBC’s passive foundation is a PassiveHaus certified system, designed to thermally encase the foundation in high performance expanded polystyrene (EPS)…

The MBC Passive Wall

Delivering a U-Value of 0.12W/m2K and designed to perform to its optimum level when used in tandem with our Passive Foundation system…

The MBC Passive Roof

400mm thickness of Cellulose Roof Insulation is precision fitted to overlap with the 300mm Cellulose Insulation of the Passive Twin Wall System…

Airtight System

Air tightness is achieved with the careful application of an internal airtight membrane sheeting, which overlaps at joints and junctions, and is sealed with airtight tape…

Passive House Technical detail

View a detailed cross section diagram of our Passive House Twin Wall system…

Understanding the Thermal Envelope

Information about the “thermal envelope” and “thermal bridging”…

Passiv House Blower Door Test

Information about the Passive House Blower Door Test…

Heat Recovery Ventilation

Understanding “MVHR” – Mechanical Ventilation and Heat Recovery…

What you Get

Passive House Essential Elements


Non Structural Elements of our Passive Homes

Thermal insulation

All opaque building components of the exterior envelope of the house must be very well-insulated. This means a heat transfer coefficient (U-value) of 0.15 W/(m²K) at the most, i.e. a maximum of 0.15 watts per degree of temperature difference and per square metre of exterior surface are lost.

Passive House windows

The window frames must be well insulated and fitted with low-e glazings filled with argon or krypton to prevent heat transfer. This is achieved by a U-value of 0.80 W/(m²K) or less, with g-values around 50% (g-value= total solar transmittance, proportion of the solar energy available for the room).

Ventilation heat recovery

Efficient heat recovery ventilation is key, allowing for a good indoor air quality and saving energy. In Passive House, at least 75% of the heat from the exhaust air is transferred to the fresh air again by means of a heat exchanger.

Airtightness of the building

Uncontrolled leakage through gaps must be smaller than 0.6 of the total house volume per hour during a pressure test at 50 Pascal (both pressurised and depressurised).

Structural Elements of our Passive Homes

Absence of thermal bridges

All edges, corners, connections and penetrations must be planned and executed with great care, so that thermal bridges can be avoided. Thermal bridges which cannot be avoided must be minimised as far as possible.

MBC Passive Foundation & Slab System
Our passive foundation and slab is a PassiveHaus certified system, designed to thermally encase the foundation in high performance expanded polystyrene (EPS) insulation, which delivers the lowest U-Vaule currently available at 0.105W/m2K.
MBC Passive Wall System
The MBC Passive Wall system delivers a U-Value of 0.12W/m2K and is designed to perform to its optimum level when used in tandem with our Passive Foundation & Slab system.
MBC Passive Roof System
The MBC Passive Roof system delivers a U-Value of 0.10W/m2K and is suitable for all roof designs (flat, pitch, barrel vault, etc), ensuring your desired building design remains unchanged.

Discuss your project with us

MBC specialise in the production of Timber Frame Passive Houses and High Thermal Efficiency Timber Frame Houses throughout the UK, for people looking to benefit from huge energy savings and reduce their heating demands by up to 90%.

MBC Timber frame


Having planned our house build for 3 years and finally deciding to go modern contemporary, it became obvious that we should consider a “ passive build” and being environmentally friendly.
The team at MBC provided us with good old fashioned honest advise, quotations and drawings that we could understand. One of the main benefits of MBC was they literally carried out everything from the passive slab, UFH and the frame thus easy to manage.

We worked very closely with the MBC team, and found them friendly, conscientious and very fair at all times. Every build has hiccups” we did and they were all resolved quickly and without any issue. I have recommended MBc many times and will continue to do so.

Hopefully we will build again and as such look forward to working with you again.

Peter Worthy

MBC provided a quality timber frame with the added guarantee of reaching excellent air tightness levels, when I compared with local builders the standards, items included and costs MBC were ahead on all fronts.
Wayne Maguire

Dealing with MBC has been a real pleasure from start to finish. “Nothing’s a problem” seems to be their motto, lots of help and useful suggestions when discussing the plans, to the standard of workmanship and helpful attitude of the site team. The MBC foundation and build part was the most stress free part of the whole build, fantastic, thank you.
Peter and Sue Purslow
Peter and Sue Purslow

We chose MBC to build our house as part of a tendering process. They scored very well on price and also supplied a passive-grade slab foundation. Throughout the design and build phases we found the whole team to be extremely skilful and very accommodating, particularly when it came to small changes due to our own oversights in the design stages. Nothing was ever a problem. Other contractors we had on the build praised the team for their workmanship and attention to detail. Were we to do it all again, we’d have no hesitation in choosing MBC.
Tony Haddon

A super insulated, timber frame house, providing exceptional energy efficiency

Designed and engineered in accordance with current building regulations

Manufactured in a controlled factory environment, ensuring superior quality craftsmanship

An affordable, competitively priced building option

Erected on site at an unparalleled rate when compared to conventional block construction

An environmentally conscious and forward thinking sustainable approach