TRUNK CLT setting standards in London

Benslow Lane by Truck CLT – WUFU analysis, Woodfibre insulation, Air and windtightness by Partel (Ampack/Schneider Holz)

Trunk CLT provided a full design, engineering, and supply and erection service for this detached house in Hertfordshire. Trunk CLT is headed by Mike Jacob and Jim Johnstone. Mike is a Chartered Construction Manager, and Certified Passivhaus Tradesperson, director at Trunk low energy and has worked in the emerging low energy construction sector for many years. Jim is a CLT and solid timber construction industry specialist. Jim has extensive experience delivering groundbreaking bespoke one off and multi-storey timber projects in London, Nationwide and abroad. It’s a positive blend of technical, practical and project management skills which ensures real quality of construction  together with passivhaus standards.


With extensive forward planning at each junction Truck CLT have been able minimise the heat losses from both a an air tightness and thermal bridging point of view. The building has a complete CLT structure with 180mm to 160mm of Schneider Holz wood fibre insulation, The building fabric is secured with a range of airtight tapes and high performance membranes all supplied by Partel.  This level of detail is consuming but where these points can slow down the project they are critical towards achieving long term efficiency and a safe building fabric. Also Truck CLT always makes up for this in other areas like for instance the projects principle structure was erected in just two days, admirable to say the least!

Project build-up

  • Highly insulated floor slab
  • Fully constructed CLT core framework
  • Internal Air tightness and vapour check layer DB90 from AMPACK
  • Externally insulated by Schneider best wood fibre natural breathable insulation
  • UV stable Monolithic TPU technology – Amapatop F Black from AMPACK
  • Counter batten and beautifully finished with a cedar cladding

​It’s one of the nicer, and technically solid projects we’ve been involved in recently. It’s also fantastic to see how the finishes can be exactly as desired.

Capture CLTCapture Schneider WF

Erection of first floor CLT with combination of Ampacoll XT60 providing a permanent air tight seal and continuing that redline of Schneider Wood fibre insulation.


IMG_0600 (1)

Both internal and external eye pleasing finishes.

WUFI Analysis of woodfibre insulation

WUFI analysis Woodfibre insulation

WUFI analysis Woodfibre insulation

St James

St James Hospital – Upgrade study using Epatherm Calcium Silicate Insulation

We have recently supplied Epatherm calcium silicate insulation to a large solid wall project in Dublin (St James Hospital).

St James Hospital

St James Hospital



These types of project are worth considering, not just because it is a hospital but because of the mixed solid wall construction and the challenges it brings.  There have been a number of research papers from noted academics over the past number of years which serve to highlight the issues, some of the myths and also to suggest actual solutions and guides. The most recent such paper is below from SDAR by Joseph Little and Benat Arregi in which they focus on a Dublin solid wall project where various measures are investigated and risks evaluated. 2016-09-28 16.33.33

Hygrothermal Risk Evaluation for the Retrofit of a Typical Solid-walled Dwelling

Another relevant paper is Historic Scotland paper 15 (By Joseph Little, Calina Ferraro & Beñat Arregi) in which various solutions are tested and analysed – this paper was particularly interesting as it highlights issues with what have become standard upgrade measures using vcls or ‘intelligent’ vcls. We have always had a particular issue with vcl’s in solid wall upgrades as it is rarely possible to have the installation to a a high enough level to avoid risk. We know technically its possible but we just haven’t seen it happen – floor junctions, services and real world issues just make it too difficult. Commercial conservation buildings also have higher humidity loads and as We like these papers as they use WUFI and dont rely on an outdated and risky assessment programme using the glazer method. (This method can have its uses but not for solid walls or flat roofs)

Technical Paper 15 – Assessing risks in insulation retrofits using hygrothermal software tools

If we take the existing solid wall – in a relatively poor condition and with areas exposed to driving rain this actually quickly rules out most types of insulation. Unless an independent consultant actually tests the wall using a Karsten tube, carries out Wufi analysis over 5-7 years using local climate data and with applicable PI insurance it is becoming clear that Calcium silicate insulation can be viewed as the most risk averse or safest solution.

Calcium silicate from Partel – Its the only ‘green light’ system in – graph from HS-15

We actually analysed this wall using WUFI with the following conclusion extracted from our formal report.

”It was interesting to note that in winter months the relative humidity increased to high 80% and will reach this figure annually for sustained periods. The highest recommended figures for Epatherm calcium silicate are actually much higher at 95%. This figure of 95% applies only if the system is fully bonded, capillary active, hygroscopic and alkaline. Equilibrium was reached 2-3 years in all cases with water content levels acceptable.

2016-08-16 09.42.46

Existing wall

There is considerable safety in choosing the EPATHERM system featuring all system parts as the simulated outputs have relative humidity below the 95% threshold.


Installation of Epatherm

A horizontal DPC would normally be recommended in such historic retrofits. There is an EPATHERM system part that would be recommended to be installed. A Chemical is injected at ground floor level to ‘create’ the dpc in the normal location thus reducing risks of moisture loads from rising damp. The Horizontal DPC by Epasit is Epasit MSP. In this case due to the existing vented basement we are satisfied that this will not be necessary in this instance.

The installation of a breathable external brick seal – Natural product – would further improve the position – if desired the product is Epasit IP237”


Insulation Guide –EPATHERM GENERAL

  1. Ensure existing Brick clean and dry and free of lose components. Use a Lime plaster (Epasit MPM1 or MPM 2) to level if required. Generally if brick in reasonable condition the system can be applied directly. Lime levelling coat is preferred in conservation projects. In is important that the wall be level before applying the system.
  2. Prime all sides of EPATHERM® etp with Primary coat EPATHERM® etg Use approximately 0.7L per m2, allow to react for 45 minutes before the next stage. Freshly sawn edges must be re primed.
  3. Apply board adhesive EPATHERM® etk with notched trowel, 4-5kg per sqm
  4. Paste and fix Indoor climate board EPATHERM® etp as closely as possible – avoid joints repositioning light switches as necessary.Avoid cross joints keeping 200mm staggered joints. 1000mm * 750mm in 30 or 50mm thickness as standard (20-160mm available on demand 20mm reveal boards available or wedge boards for floor connections) If surface is smooth use plastic mushrooms to affix boards in addition to adhesive. In all cases above 3m us 5 plastic mushrooms per board.
  5. Fill all joints and unevenness on the surface with EPATHERM® multi-eti also applying a base coat of plaster 4-5mm deep, 1-2kg per m2
  6. Insert EPATHERM® etw Alkali – resistant glass fibre fabric reinforcement mesh into Multi-eti (5)
  7. As the first layer dry’s apply a Finish coat of EPATHERM® multi-eti to desired finish.

The application is proposed as follows: -

  1. EPATHERM® etk Board Adhesive
  2. EPATHERM® etp Indoor climate board with Primed coat EPATHERM® etg
  3. EPATHERM® multi-eti also applying a base coat with EPATHERM® etw Alkali – resistant glass fibre fabric
  4. EPATHERM® multi-eti finish coat


Unique system advantages

  • Insulation and regulation of room air conditions
  • Optimal fire protection
  • No health risks – purely mineral composition
  • High alkalinity prevents mould growth
  • Easy and flexible application
LUNOS Silvento extract fan

Refurbishment in Portobello – LUNOS Ventilation in conservation

Garden view

Garden view

We were delighted to be contacted by Diarmaid Brophy Architects – A forward thinking architectural practice with obvious architectural talent but balanced with a good knowledge of how buildings work.

The project involves the full refurbishment of this Protected Structure – a mid-19th terrace single storey over basement property with a 2 storey return to the rear. While the property retained much original fabric, it was in a poor state and was fully refurbished to create a modern comfortable home, while retaining its authentic character.

LUNOS Silvento extract fan

LUNOS Silvento extract fan

Our task – working with the architectural team was to address the ventilation so that the indoor air quality would match that of the rest of the building. As the building is protected and of solid brick construction the exterior grills had to be sympathetic to the buildings character. This can be accommodated either through the provision of pre coloured grills or bespoke grills provided by the builder.

The builder in this project was Principal Construction – a heritage and grant listed contractor who brought things together onsite and actually installed the LUNOS system. DMB0915HS10

Dooroge Woods

A-Rated Dooroge Woods development opts for LUNOS & Ampack

Build tight Ventilate right is often mentioned but not always adhered to. Not so with the exclusive Dooroge woods housing development in Dublin. The main contractors are Greyfields developments who have a history of high quality developments via Marhan construction.

Dooroge woods is a development of 37 luxury 3, 4 and 5 bedroom detached homes close to swords in Dublin. The aim of the developers was to deliver a high performance development that would deliver in terms of quality in all aspects, not just a A2 rated property.
2016-03-11 10.03.36Impressive airtightness was demanded and so Ramstown Timber frame were appointed together with the Ampack Airtightness range. Nicky Stafford of Ramstown timber frame is experienced in passive house building and airtightness and was an interesting choice have worked in ‘one off’ housing most recently.

The quality control procedure from passive house single dwellings is welcomed in multi-unit development and has seen the development meet or exceed the brief where airtightness is considered. 

Greyfield developments as modern developers are acutely aware of the air quality issues and are keen to continue to develop a long term reputation for high standards.

Accordingly we were brought in to present LUNOS decentralised ventilation systems. The issue of quality control with ducting installation and future cleaning was  a factor when LUNOS were appointed. Dooroge LUNOS

The chosen LUNOS demand controlled ventilation system (DCMEV) operate on a completely decentralised system – Ducting is right through the wall via pressure controlled inlets and intelligent extracts that adjust automatically relative to time temperature and humidity. LUNOS fans have expected lifespans of over 30 years and can cost €5.00 per year to run for the overall system. With this system indoor air quality is assured for decades.


LUNOS Silvento smart extract fan


LUNOS Silvento complete




LUNOS ALDR fresh air inlet


Ampack Ampatex DB90

Ampack Ampatex DB90

Lester Naughton 1

”Barn House” features Ampack Air and windtight systems.

Lester Naughton 2New Zealand born Galway based Architect Lester Naughton delivered this unusual and beautifully designed ‘barrel roof” passive level dwelling in a coastal location in Galway. You could be forgiven for initially thinking the design is unsympathetic to the area but the design closely reflects the typical barn or shed common to the area. This type of roof also reduces the building height by up to 1.5m. The building is a split level with coastal views.

The building appears uncomplicated but achieving such clean lines, finishes and the hidden low energy precision requires a builder with an impressive skillset. Greentec Eco homes were selected and again delivered to the usual high standards.

A comment from Lenni Antonelli at sums up Lester Naughton and Niall Dolan of Greentec.

       I ask Naughton if hitting the passive house airtightness target of 0.6 air changes per hour was straightforward. “With this guy,” he says, pointing to builder Niall Dolan, “yeah, it was.” Dolan in turn praises the quality and detail of Naughton’s design drawings. 

Lester Naughton 3

We’d like to think the tapes and membranes from Ampack helped then along the way ! In this project Niall and Lester used Ampacks DB90 & DB2 membranes internally and externally Protecta and Aero. This essentially applies the market leading 10 year system warranty of Ampack to the high performance timberframe.


fig_ampatex_db90_p1_FA fig_ampatex_db2_p2_FA





Ambitious Pat Doran Enerphit features compaCFoam

Enerphit-upgrade-Dublin-home-03 Enerphit-upgrade-Dublin-home-04 pat_doran_logo_green

Pat Doran construction were chosen to upgrade this south Dublin residence. The project had been proposed as Enerphit but suggested additional costs had brought this into doubt before the involvement of Father and Son team Pat and Paul Doran. “We said it might be possible to do Enerphit without it costing more, “From our experience and knowledge we were able to say that the budget was sufficient, that the house had a good orientation and form factor for passive house” says Paul Doran.

Pat Doran construction specialise in Passive house, Enerphit and NZEB (NEZB) building and through experience and specialist training are offering real low energy building expertise at reasonable prices.

Enerphit-upgrade-Dublin-home-05 Enerphit projects are more challenging as details must accommodate the existing building and find ways to sympathetically upgrade the junctions to appropriate levels. The importance of having either an experienced or extremely knowledgeable contractor and design team is important. This skillset enables cost effective solutions for these difficult junctions. Airtightness and thermal bridging detailing are often the most challenging issues.


An example of one such junction was the large steel posts which while internal were connected to the new foundation. Pat Doran construction opted to use compaCFoam to support the steel. compaCFoam is possibly the highest performing thermal isolation material with thermal conductivities as low as 0.038. It is available in different density classes from CF 100 to CF400. CF 100 is typically used for thresholds and CF400 for point loads. CF400 is shown in the above photo.

Just how strong is compaCFoam ? Its surprisingly so – there is a  Datasheet  here but to get a visual – you can build on it, drive on – pretty much whatever you need to do depending on the load and density class.

compacfoam loading 4

compacfoam loading 2 compacfoam loading 3

compacfoam loading

 Photos – from

Is Mechanical Ventilation needed?

Modern homes and buildings are achieving greater levels air tightness with and have requirements for substantial levels of insulation. This dramatically affects how the building performs from a humidity, moisture management and fresh air point of view. The number of studies carried out on existing buildings are limited but generally conclusive. Natural ventilation can be demonstrated to comply from a regulatory point of view but real life testing conflicts.

There are many ventilation options on the market at the moment from centralised to decentralised heat recovery to demand controlled, positive pressure ventilation, passive stack ventilation, natural ventilation, trickle vents and purge ventilation. Studies tend to prove that without adequate mechanical ventilation in the appropriate locations it can  lead to moisture build up and condensation issues. This follows on to mould growth and poor indoor air quality.

In renovation projects increased insulation in walls and roofs is called for to increase building performance. If naturally follows that airtightness is improved in upgrades. Prior to the renovation the ‘leaky’ building fabric provides enough unplanned fresh air to maintain air quality – comfort and heating costs are sacrificed in this scenario. The safe solution is, to install an adequate mechanical ventilation system that best suits you and your house. These could be any of the options below

  1. MEV – Mechanical Extract Ventilation. Manually controlled Extracts  to wetrooms and fresh air supplies to living rooms – LUNOS Silvento ec + ALDR
  2. DMEV -Time, Temperature and humidity controlled Extract Ventilation controlled Extracts  to wetrooms and fresh air supplies to living rooms – LUNOS Silvento FK + ALDR
  3. Hybrid Systems-  Timed Extracts to wetrooms and Heat recovery to living rooms – LUNOS Silvento ec + E2 +Nexxt
  4. MVHR Systems Timed Extracts to wetrooms and Heat recovery to living rooms – LUNOS EGO + E2 + Nexxt

Some relevant topics that need to be noted and discussed when choosing a ventilation system are not only the cost.

  • SFP specific fan power or energy consumption, this can fluctuate depending on the system
  • CE marking-  have they been tested and references of where they have been used?
  • Noise level or db level and at what distance is that measured away from the fan. LUNOS measure at 1m, where most supplies measure at 3m.
  • Pressure difference. Is it capable of maintain the extraction rate regardless of external conditions or meeting the air extract demand of a dwelling eg. Wind, exposed area, coastal region. LUNOS radial fans are superb in this area.
  • Warranty with the system, are parts easily replaced if something breaks
  • How often do filters need to be changed or cleaned
  • Efficiency of the system
  • If it is a heat recovery system how much heat does it recover summer ventilation mode
  • Can the system be upgraded

One of the largest general studies was carried out in Germany- 5530 units!. Building standards are higher there and yet 21.9% of apartments had visible moisture damage. Visible damage is a sign of serious issues but health can be affected much earlier and so it is likely that up to 50% of said dwellings have issues. 

IEMP 2003 Causes are poor ventilation, high moisture/humidity and thermal bridging. Solutions would start with non user controlled ventilation.




The following study ”Evaluation of the Impact of Retrofitting a Mid-terrace 1950’s House in Dublin on Indoor Air Quality” in 2010 *concludes in a monitored test environment that good indoor air quality is not assured when complying with building regulations through the input of intermittent vents and fresh air supplies. .

LUNOS ventilation study


Natural ventilation is flawed for many reasons but the uncontrolled fresh air supply on cold days or exposed houses often mean that said vents are blocked. The actual extract would normally create the demand for fresh air intakes but if the extract fans are not running constantly at a minimum speed fresh air will not be maintained.

Lunos have three main types of system solutions,

LUNOS- Demand Controlled Ventilation system or decentralised MEV as it is noted under the SEAI DEAP software. This performs very well in practice and in DEAP software.  The SFP is only 0.35 W/l/s for the RA 15-60 . This is a cost effective solution which can be upgraded to heat recovery in the future as it also uses the LUNOS 160 series sleeves. Air supply is attenuated for sound, air flow and is also filtered. The sound difference from inside to outside is quite high of 55db. Filters are of a high grate G2 filter class which can be washed dried and reused. The system is uncomplicated to install as  air supply vents are non mechanical while extractor fans in the wet areas can be wall or ceiling mounted, humidity sensors can controls the speed of the fan boosting or slowing the fan depending on the humidity in the air.


Lunos – MVHR decentralised mechanical ventilation with heat recovery has one of the highest heat recovery efficiency on the market has an average heat recovery of 90.6% for the e2 and incredibly low SFP generally but the lowest reading is for the LUNOS e2neo model with 0.54W/l/s. There are three types of fan units for the Lunos MVHR system – e2 Nexxt and ego. The e2 is for all the habitable rooms and the ego are used for all the wet rooms, The Nexxt unit is larger and can ventilate large areas. E2 operate in pairs they are made up of a honey comb designed ceramic core element making up the majority of the unit, internally the unit has a fan which alternates direction from extract to supply every 70 seconds. While the fan operating in extract the hot air is charging the ceramic core heating the unit and then after 70 seconds the fan changes direct and supplies fresh air. While the new fresh air is passed though this now heated ceramic core element it heats up and ventilates through the house. 


Lunos – Hybrid decentralised heat recovery ventilation incorporates both types of Lunos systems together MVHR and DCV. This is system would have an approximate efficiency of >80%. It consists of e2 units in all the habitable areas and extractor fans on timer delay modules in the wet areas. The extractor fans would be wired to operate to come on every 4hr for 15mins and can be manually operated also. The majority of the ventilation would be by the e2 units.  


* Source – ”Evaluation of the Impact of Retrofitting a Mid-terrace 1950’s House in Dublin on Indoor Air Quality” by Aereco  


LUNOS Launch in Scotland

We would like to welcome Ken Todd and Phil Slater to the LUNOS network. Together they operate  MGO  - Sip systems throughout the UK and bring a wealth of experience to an exciting line of product development from LUNOS. They will be available for sales, design assistance,  product demonstrations and CPD’s for Scotland.

Ken has been involved in offsite construction and property management/development and brings a keen understanding of the requirements and issues with ventilation in new and old properties.  Phil is technically focused, innovative and creative – a natural fit for LUNOS decentralised ventilation systems.

LUNOS are market leaders in the German decentralised ventilation market and pioneers of decentralised heat recovery ventilation. Decentralised heat recovery has continued to grow in Germany (The most developed MVHR market worldwide) where centralised MVHR had a decline of approximately 8%. The decentralised ventilation market is becoming more important worldwide and LUNOS as market leaders are continuing to develop incredibly efficient systems while maintaining customer a focused design ethos. This is particularly evident in the new Nexxt unit which is available of this week.

To contact the team please visit LUNOS UK here

MGO SIP Systems

Suite 195, Station Square,
Inverness IV1 1LD
01381 620708

Partel LUNOS Scotland

Flat roof option 1

Flat roof construction – an expert guide to moisture management

Interstitial condensation : – Can all flat roofs be treated in the same way ?

It’s a question we get asked quiet often – is there a rule that I can apply in general terms too all flat roofs? Unfortunately there isn’t due to the mix of factors that affect moisture. This is an area we specialise in and can provide a market leading system warrantied flat roof constructions. Read more about our unique warranty here

  • Orientation – North facing roofs have lower solar gain and therefore receive less heat and will have lower levels of back drying.
  • Colour of outer membrane – Light coloured membranes reflect more sunlight and therefore have lower levels of heat transfer to the roof than the same roof with a dark membrane.
  • Insulation location – Is it above the Deck , within the deck, under it or a mix of both !

We have below provided 4 solutions that can cater for all types of flat roofs providing an option for safe solutions. Insulation is neutral (Can be by any manufacturer)


Un-ventilated construction -Insulation on top of the supporting structure.

Quality of application and blower door testing is critical towards achieving results.
Flat roof option 1

Construction structure from the inside to the outside

  1. Supporting structure
  2. Air sealing / vapour barrier – SD >100- AMPACK CENTO
  3. Insulation
  4. Closed roof system part – Possibly Slip / separating layer
  5. Closed roof system part – Sealing the gap ≥ 1.5%
  6. Closed roof system part – Extensive protective layer
  7. Final outer roof covering


Ventilated construction:

Quality of application and blower door testing is critical towards achieving results. The air layer should be larger than currently accustomed to at 100mm to allow satisfactory airflow.

 2. Ventilated Construction

  1. Final ceiling
  2. Cross battens
  3. a)Air sealing / vapour barrier or - AMPACK DB90 or AMPACK VARIANO b) Airtight supporting structure,
  4. supporting structure
  5. Insulation
  7. Slope layer (battens)
  8. Air layer – **NB recommended 100mm for adequate air flow.  
  9. Supporting structure for sealing
  10. Closed roof system part – Possibly Slip / separating layer
  11. Closed roof system part – Sealing the gap ≥ 1.5%
  12. Closed roof system part – Extensive protective layer
  13. Final outer roof covering


Un-ventilated construction -Insulation within and on top of the supporting structure.

Quality of application and blower door testing is critical towards achieving results. Vapour control layers for construction 3 should always allow for backdrying  and have an SD of less than 10- ideally variable – see AMPACK VARIANO. The Glaser method will fail to calculate this system accurately and therefore always recommend a  site specific WUFI analysis.

This construction has a minimum rule of thumb between the insulations – 2/3 to 1/3 with a  minimum of 1/3 of insulation above and 2/3 below. The upper part can be above 1/3 which improves the situation. This buildup can mitigate for light membranes and colder roofs due to shading.

2. un ventilated Construction 2 layers of insulation


  1. Final ceiling
  2. Cross battens
  3. a -Air sealing / vapour barrier or - AMPACK VARIANO b- Airtight supporting structure,
  4. supporting structure
  5. Insulation
  6. Construction waterproofing – Not for building physics AMPACK AERO
  7. **Additional Insulation – Minimum 40mm**
  8. Closed roof system part – Sealing the gap ≥ 1.5%
  9. Closed roof system part – Extensive protective layer
  10. Final outer roof covering

We simulated this buildup in WUFI using a  worst case scenario – North facing and a lightly coloured membrane. We allowed for a stressed situation using a q50 of 5 (Air infiltration) at the plywood bord)

WUFI analysis
Total water content


Plywood board


Mineral wool


RH and temperature


We have been asked to simulate this buildup without the inner insulation but still with the variable – Ampack Variano membrane  - We know it not to be a recommended buildup but are able to demonstrate in WUFI that the water content % in the air layer or batten space ranges is not ideal. The medium is the difference here- Air/Insulation and the buffering capacities.

Batten space moisture content

When compared with the same space when full filled the water content is between 0.5% and 2%. (Average 1kgm3)

Mineral wool moisture content


Unventilated construction -Only in special cases – insulation within the structure

Non vented structures have a lower tolerance for error. Quality of application and blower door testing is critical towards achieving results. Vapour control layers for construction 4 should always allow for backdrying  and have an SD of less than 10- ideally variable – see AMPACK VARIANO. The Glaser method will fail to calculate this system accurately and therefore always recommend a  site specific WUFI analysis.

4. insulation in structure

  1. Final ceiling
  2. Cross battens
  3. a-Air sealing / vapor barrier or - AMPACK CENTO b-Airtight  supporting structure,
  4. supporting structure
  5. Insulation
  6. Closed roof system part – Possibly Slip / separating layer
  7. Closed roof system part – Sealing the gap ≥ 1.5%
  8. Closed roof system part – Extensive protective layer
  9. Gravel Protection layer

References : reference

Architectural or Engineering Technician – Position Vacant

Job Description

We currently have an opportunity in the area of Technical Sales. We are preferable to someone with a background in architecture, engineering or construction.

The job would entail learning and training in passive house principles, low energy building, building physics including WUFI software, airtightness and thermal bridging solutions.

In addition the successful applicant would be required to manage and develop existing and new sales.


Skills and experience

Architectural or Engineering Technician with 2 years experience in construction related activities.


If interested, please forward your CV to