Insulating the panels onsite and airtightness

After, the team installed the roof and wall panels, they started to insert the Eco-beads which are little insulated beads that are locked into tightly packed honeycomb matrix with a water based adhesive. The job of the beads is that they make our homes warm and comfortable to live in.  By insulating on site one the panels have been put into position, means that these can easily flow all around the new frame and means there are no gaps or joints where heat can escape.



The team fitted airtightness tape around the new windows and doors and penetrations, it is aluminium foil tape providing a vapour seal join. Next, the Wraptite Membrane was sealed onto the insulated panels; it is a barrier that stops unwanted ventilation heat loss. After all jobs were done the team cleared the whole area outside the building.


The week began with team placing timber battens outside the homes onto the wall panels, they are strips of wood (but could be made of other materials such as: metal, plastic or fiberglass,) that are used to fix siding materials such as tile or shingles. The team then, fixed plastic skirting onto the bottom of the wall panels. Finally, they put in the roof tiles which are to block rain and are made from terracotta or slate.

Over the past couple weeks, (while this was happening) the process did not cause any distractions or disruptions. During this time the site manager informed us about the progress of the project, it is all going very smoothly.

Erecting the TCosy panels

The team begun by taking down the old porch which they will replace with the new one.  They drilled into the wall to create holes for the Mechanical Ventilation and Heat Recovery system which will help to create a good indoor air quality and a comfortable draught free environment. Following this the Beattie Passive team erected the steel frame which will help to support the new roof and walls panels. During this work, the site manager informed both of us about the work and the progress. He explained to us what they are going to do and kept us updated about the work each day.


MVHR Holes Drilled

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Steel Frame Erected

After drilling the walls for both houses the team stripped down the roof and installed new timber frames which will support the TCosy panels. As the week neared to the end, we can see the project has moved forward a lot, all the external building area has been tied up and there is no disruption.

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As the work progressed and the TCosy panels and crane arrived on the site, the team continued working so hard with the preparation of how they will install the panels. They removed all the old windows for both houses which will be replaced with new triple glazed windows. During every step of the installation, they keep us and the neighbors informed about the noise and any disruption. The team installed all Beattie Passive wall panels which came together with triple glazed windows.

At this point, we are so happy because the project is moving forward quickly and we are delighted to be part of it.

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Retrofit Plus Insights by Prof Lubo Jankovic, Birmingham City University


Retrofit Plus project transforms existing poorly performing buildings into Passivhaus standard buildings. The retrofit is carried out by Beattie Passive using their TCosy system. BCU are providing research for this project to assist the design team with the retrofit strategy.

At the start of the project the objective was to go for full zero carbon retrofit. Half way through the project a national scheme called Green Deal was discontinued and the funding for renewable energy in Retrofit Plus disappeared as result. Our revised objective was to put the buildings to be retrofitted onto a trajectory to zero carbon so that full zero carbon performance can be achieved at a later date.

The buildings to be retrofitted were provided to the project by Birmingham City Council (Figure 1).


Figure 1 Two semi-detached houses to be retrofitted

Establishing pre-retrofit base case

 A 3D laser scan was carried out by the University, in order to create a model that can be used for off-site measurements by the project lead industrial partner Beattie Passive, in order to manufacture the retrofit system in their factory. Eight different laser scans were taken, one high resolution and one low resolution from each of the corners of the buildings, and the scans were ‘stitched-up’ to create a unified model (Figure 2).


Figure 2 Unified point cloud from multiple 3D laser scans for off-site analysis and measurements

Subsequently, BCU staff delivered training to Beattie Passive to enable their staff to use the 3D scan for off site measurements. This minimised the travel for Beattie Passive from their base in Norfolk to the retrofit site in Birmingham.

A team of surveyors was brought in to establish details about construction types, such as materials, layers, thicknesses, condition of the constructions etc. The buildings were identified as Wimpey No-Fines type, characterised with concrete construction – concrete without the sand fraction. This building type was constructed with concrete cast in situ and was not fitted with any thermal insulation. Over 300,000 buildings of this type have been constructed in the UK, and most of them require urgent retrofit.

A number of thermal images of the building were taken, and these corroborate the absence of thermal insulation in walls (figure 3). Brighter colours in this Figure indicate areas of high heat loss to the outside that coincide with the internal positions of central heating radiators.


Figure 3 Thermal image of the building with bright colours indicating high heat losses from central heating radiators

As result of the high heat losses identified through the survey, building occupants spend more energy to keep warm. Even with higher energy bills it is harder to be comfortable in a house where most of the heat disappears through un-insulated walls.

A University PhD student carried out a detailed internal survey in order to create CAD drawings of the building.  These helped to create a series of computer models that will be used for design analysis (Figure 4).


Figure 4 computer model development from IES Virtual Environment (top left) via DesignBuilder (top right) to EnergyPlus (bottom right) and JEPus+EA (bottom left)

This computer modeling path was chosen to enable initial student input in IES VE to be transferred to a modeling tool capable of calibration and design optimization (JEPlus+EA).

Finally, the computer model of the building was calibrated with gas and electricity data obtained from the house occupants for the past two years. The results of the calibration determined the parameters of the model that resulted in the minimum error between computer simulated energy consumption and actual energy consumption recorded in the energy bills. The errors of the calibrated model were 0.17% in respect of electricity consumption and 0.33% in respect of gas consumption, meaning that the model was 99.83% accurate in respect of electricity consumption and 99.67% accurate in respect of gas consumption.

The model calibration was the final stage of establishing the pre-retrofit base case, and it resulted in an accurate computer model for design analysis.

Design analysis

The pre-retrofit base case in the previous step created an accurate computer model that can be ‘pushed and poked’ to see what happens with different design interventions. Unlike the most of design projects in which up to half a dozen model variations are investigated, we adopted a multi-objective approach in which several thousand design options were to be investigated.

The technical parameters for optimisation were:

  • three different thicknesses of TCosy wall insulation: 150mm, 200mm and 225mm, combined in pairs with the identical TCosy roof insulation thicknesses;
  • infiltration air changes per hour;
  • fuel type (gas or biomass);
  • lighting power density; and
  • two different PV arrays (East side of the roof only, and East and West side combined).

The user behaviour parameters for optimisation were:

  • room set temperature and
  • clothing level.

The objectives of the optimisation analysis were to minimise CO2 emissions and maximise thermal comfort. A total of 4860 simulation cases were investigated in order to select a subset of best cases to be considered for final design.

The results of design analysis are shown in Figure 5, where a trajectory from a minimum intervention to zero carbon retrofit is plotted using the results of individual design simulations.


Figure 5 Trajectory to zero carbon

The trajectory in Figure 5 starts with a minimum intervention in point 1: 150mm wall and roof insulation TCosy system is added, whilst using the existing gas boiler, keeping the infiltration rate high, and without adding any PV. The resultant room set temperature is low (16 oC); the level of occupant clothing is high (1.4 clo), indicating the use of clothing levels higher than woolly pullovers; and carbon emissions are high: 2,565 kgCO2 per year. As we progress from point 1 via point 2 to point 3, which is based on TCosy 225mm insulation, the room set temperature increases to 21oC, the clothing level reduces to 0.8 clo (a shirt instead of a pullover) and carbon emissions are reduced to -336 kgCO2 per year with the application of renewable energy. The overall reduction of energy consumption is estimated to be significant, well over 80%.

These results indicate that deep retrofit does not only result in energy consumption reduction and carbon emission reduction, but it also creates opportunities for improvements of occupants’ wellbeing.

Prof Lubo Jankovic, Birmingham City University

Preparation for Retrofit Panels

As ground work is nearing the end, the team started with finishing the drainage work for Catherine’s house, they installed new pipes for her kitchen and toilet and are moving the old drainage for a new one.

They also finished preparing the external area for both houses where they dug trenches and built the foundations where new outhouses will be. At the end, they cleared the remaining rubble and kept the slabs which they removed from front parking at the safe place. Foundation Brackets have been fixed to our houses these will be used to fix the new panels to the wall.

The project is moving forward and the new Beattie Passive team has arrived, they are very polite to both of us. The explained to us about what are they going to do and keep us informed about the work. They started by installing plastic lining membrane to the outbuildings wall which will help to prevent the damp for both houses. Also, Scaffolding has been installed to the whole outside building to support and help the builders and their work.  At the end of this week all the ground work has been done and we are very happy because most of the structure work has been done for outbuildings and there are not any disruptions.










Foundations and trenches

As the ground work continue, the team started with finishing the drainage work for my house, they installed new pipes for both kitchen and toilet. Also, they prepared Catherine’s external area and dug trenches around her external building as well as moving the old drainage for a new one where the TCosy will be.

Both of our outbuildings have been prepared ready for foundation and all the rubbles been cleared too and very safe to go in and out.

I found this week not difficult for both of us, as we are very happy because most of work has been done outside the house and doesn’t affect us, no dust inside our home and we hardly hear any noise.

To be honest, we are delighted as the project is moving forward very fast and soon everything will be done.






First week – preparing the homes for retrofit

The project begun on Monday 26th September at 8am, we communicated very well with the contractor and his team. They let us know about the work and what needs to be done for the week. They are very nice and polite to all of us and they helped Catherine to remove all of her unwanted stuff before they begun the work.

They started with clearing the external area of our homes then dug trenches around the building. Our utilities were located and drainage is currently being moved outside of the where the TCosy will be. Both of our outbuildings have been demolished and rubble being carted away. It is great that the outbuildings are being replaced as they are so damp and cold – not a nice space at all to use.  As well as this the electrics were made safe in the outbuilding and building surveyed for future electric installation. All in all a busy week.

I found the whole process not difficult for us as most of work has been done outside the house and doesn’t affect our daily life routine and now I am very happy that the project is moving forward. Not long to a new home!


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Introduction to the project

The Retrofit Plus Research Project is a collaboration between Beattie Passive, Birmingham City University, InteSys and iZdesign under the Innovate UK initiative for ‘Scaling up retrofit of the nation’s homes. The project is retrofitting two houses to achieve EnerPHit performance. The project aims to drive innovation in energy retrofit of homes that achieve up to 100% carbon emissions reduction, drawing upon academic, technology start-up and private sector expertise.

Beattie Passive TCosy™ are using their innovative system to transform two semi-detached houses (owned by Birmingham City Council), using their highly insulated offsite system. Using Passivhaus comfort and energy efficiency principles, the TCosy™ system transforms houses and delivers dramatic cost, time saving, health and environmental benefits.

The TCosy™ delivers the following benefits for the council and their tenants:

  • 2 houses retrofitted to Passivhaus standard – TCosy™ achieves Passivhaus standards of build and incorporates Passivhaus Certified windows and doors and a Mechanical Heat Recovery and Ventilation system. This delivers a high performance, high quality home
  • Fast on-site build – the Passive Panel system will be installed onsite in a few weeks
  • Limited disturbance – residents can remain in their homes for the duration of the retrofit
  • Lift tenants out of fuel poverty – reduces heating requirements and energy bills by up to 85%
  • Creates healthier, more comfortable homes to live in
  • A new look home – we work with the council to design a completely new external façade
  • Regular engagement with your tenants to ensure they understand the process and benefits of the Retrofit
  • Increased Asset Value of you housing stock

Retrofit Plus Partners

Project websiteRetrofit Plus

Meet the residents of the next Beattie Passive TCosy Project

Elisabeth and Catherine will be sharing their thoughts and experiences throughout the retrofit process. 

Keep up to date with the project through their regular posts. 

Insights from Elisabeth:

My daughter and I have lived in the house in Birmingham for five years now.

In the summer, our house is hot\warm as well as comfortable to live in. However, sometimes the floor is quite cold and there is lots of dust but apart from that our house is a great building to live in during summer. In the winter, it is a different story, our house is uncomfortable to live in because the house is too cold and damp. We can’t live without switching on central heating on all the time and still the house is not warm enough, for that reason I spend a lot of money to pay energy bills and sometimes I can’t afford it.

From our discussions with the team at Beattie Passive, after the retrofit, we are expecting to have an external new building with new triple glazed windows and new doors, a much warmer house during winter and comfotable during summer. We are hoping to save money which I spend on gas and electricity bills as well as being able to save energy and reduce carbon emission. Another great thing is that by having a ventilation system we will live in a dust free house and much healthier lifestyle. Can’t wait!