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Comment PATHWAY TO PASSIVHAUS: LET’S CLEAR THE MISUNDERSTANDING By Allan Doris, Branch Manager at commercial roofing contractor BriggsAmasco. The requirement for Passivhaus-level performance in Scotland’s new-build homes from January 2025 is a welcome government initiative, as is the Passivhaus standard across the UK. In 2022, UK government figures revealed residential emissions accounted for 17% of the country’s CO 2 output, an issue that must be addressed if our net-zero ambition is to be met. But are stakeholders truly ‘across the detail’ when it comes to delivering Passivhaus standard for homes, schools, colleges and roofing projects throughout the commercial and industrial sector? If not, could we be storing up a host of costly retrofit issues in the drive to achieve optimal airtightness. There are plenty of positives to be taken from the Scottish Government’s introduction of Passivhaus legislation. It is claimed that constructing to the standard reduces a building’s heating demand by 90%, whilst the improved interior air temperature consistency enhances year-round occupant comfort and wellbeing. But do we have the necessary technology, tools, materials and understanding to deliver the Passivhaus building tolerance levels required? From my experience thus far, the answer to that question, is no. Tolerance discrepancy There are major obstacles to achieving construction tolerances being considered by Passivhaus consultants. For example, for a recent roofing project involving BriggsAmasco, the advocated machine-manufactured insulation had an either way 5mm tolerance. This was despite Passivhaus consultants stipulating a 1.5mm tolerance. This is not an uncommon discrepancy. But rather than engaging with project stakeholders to devise a solution to counteract the 3mm tolerance shortfall, the burden of Allan Doris responsibility is handed to the main contractor. In the case of the project involving BriggsAmasco, Passivhaus consultants floated the idea of craft trade tools being used as part of an onsite cutting process to achieve the 1.5mm tolerance, but with the best will in the world, that just wasn’t possible. As stated, there are many reasons to welcome the coming of new-build Passivhaus compliance, but currently the technology, tools and equipment are not available to make it happen. Therefore, I believe the time is ripe to create an open forum for building stakeholders to convince Passivhaus consultants of the need for greater consideration in respect of building material manufacturing tolerances. This is also important to debating whether craft trade tools regularly used onsite are capable of meeting the “In my opinion, the only way to Passivhaus success is through extremely close collaboration between all parties from the early project stages” standards described or set out by the Passivhaus Institute. Collaboration In my opinion, the only way to Passivhaus success is through extremely close collaboration between all parties from the early project stages. Although the Passivhaus standards are well written and informative, more focus is required on the practicality of meeting them on site. When additional products are required such as expanding foams – to fill gaps between insulation boards – the standards contain a lack of approved products and solutions that have been tested in Passivhaus applications for longevity and durability. Facing challenges As a proactive contractor, we are looking at trialling different materials to support the Passivhaus project requiring 1.5mm tolerances. But such research is time-consuming and costly, involving materials that our installers may not be familiar with. As a BriggsAmasco Branch Manager, I like to be aware of the technical challenges my site teams are likely to face. But in order to develop solutions to meet Passivhaus compliance, contractors such as ourselves are 28 TC MAY <strong>2024</strong>
sailing into unchartered territory. Again, the issue would not be as acute if Passivhaus consultants, aware of the tight tolerances we were having to work with, supported us by highlighting a range of materials and ancillary products that could help achieve compliance. However, the onus remains with the specialist contractor. Demonstrating concerns In terms of additional proactive measures taken to highlight our concerns regarding building tolerance compliance, in August we invited Passivhaus Trust representatives to a demonstration day. It was held at BriggsAmasco’s regional Cumbernauld offices and involved our technical teams creating a builtup roofing system within a controlled warehouse environment. Despite there being no exposure to external elements, foot traffic or building movements, we were unable to achieve 1.5mm tolerance compliance. A representative from a “The time is ripe to create an open forum for building stakeholders to convince Passivhaus consultants of the need for greater consideration in respect of building material manufacturing tolerances” leading roofing membrane manufacturer was also in attendance. We have supplied Passivhaus consultants with our optimal tolerance outcomes. Realistic ambitions Until technology progresses to significantly improve onsite cutting efficiencies, I believe consultants must be more realistic with their desired outcomes for Passivhaus compliance. Many variables provide a barrier to even the most skilled operators achieving 1.5mm tolerances: human error, manufacturing tolerances, materials being damaged en route to a roof. Hence, the level of cross-party cooperation and product evolution is yet to keep pace with Passivhaus ambitions. The challenge now for building stakeholders is to make Passivhaus compliance achievable, regardless of how tight the required tolerances. It’s why I’m imploring all interested parties from designers, manufacturers and contractors through to structural engineers and Passivhaus consultants to bring their thoughts, ideas and concerns to the table. It will be crucial to the UK’s homes, schools and roofing projects, commercial and industrial, being built with airtight efficiency. Contact BriggsAmasco briggsamasco.co.uk For further r inform ation or a hire quotation call 01858 412 100 Email: sales@cookerhire.com www.cookerhire.com
Page 1 and 2: MAY 2024 >>> RETENTIONS UPDATE •
Page 3 and 4: Editor’s Intro MATT DOWNS EDITORI
Page 5 and 6: REGULARS 12 NFRC ROOFING TALK James
Page 7 and 8: It’s a Wrap. When it comes to max
Page 9 and 10: Maximum reliability. Minimum fuss.
Page 11 and 12: LEARN MORE You may just see a roof.
Page 13 and 14: TAKE YOUR ROOFING BUSINESS TO THE N
Page 15 and 16: e worth the investment. The success
Page 17 and 18: WestWood Liquid Technologies Limite
Page 19 and 20: ISOLINE LOW LINE is our easy to ins
Page 21 and 22: “CCPI forms part of the bigger pi
Page 23 and 24: oofs poses a challenge for designer
Page 26 and 27: Ventilation ROOM TO BREATHE: HOW TO
Page 30 and 31: Total Talk: Pete Hollingworth “TH
Page 32: Total Talk: Pete Hollingworth Conti
Page 36 and 37: Article Metal Cladding and Roofs WI
Page 38 and 39: Product Focus FOCUS ON THERMAL PERF
Page 40 and 41: Cladding & Facades Updates TRIPLE B
Page 42 and 43: Comment HOW PRACTICAL IS A NET ZERO
Page 44: Knauf Insulation Tech Talk TAKING H
Page 47 and 48: accumulating in the stone or brick
Page 49 and 50: 40V XGT 2 PIECE KIT: BRUSHLESS COMB
Page 51 and 52: Nail it down with confidence DON’

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