The design and construction of a retirement village in Solihull achieved a BREEAM Very Good rating, thanks to Accredited Professional services offered by Darren Evans. The assessment offered unique challenges, which were met as a result of working on the scheme from pre-assessment all the way to post-construction review.
The project, delivered for the ExtraCare Charitable Trust by Vistry Partnerships West Midlands, also benefited from thermal modelling and compliance calculations. Value engineering of the building fabric specification ensured that performance targets were met alongside the BREEAM rating, without over-specifying.
ExtraCare retirement villages provide a range of facilities to offer residents comfortable living with a full and diverse selection of social and leisure opportunities. Solihull ExtraCare featured 300 homes, and a village centre that included a gym, bar, restaurant and retail units.
The mix of residential and non-residential space meant juggling separate workloads in terms of compliance.
The residential portion required Standard Assessment Procedure (SAP) calculations to demonstrate compliance with Part L of the Building Regulations and produce an Energy Performance Certificate (EPC). Calculations using the Simplified Building Energy Model (SBEM) methodology were carried out for the commercial portion, and to issue a Commercial EPC.
Site constraints meant that the building fabric specification - especially the U-values and insulation specification - had to be as tight as possible while still achieving compliance.
“Meeting thermal and acoustic requirements, especially between residential and non-residential areas, is a challenge,” explained Matthew Curry, Design Co-ordinator at Vistry Partnerships West Midlands.
“Darren Evans helped us with the energy assessment and compliance calculations. They carried out very detailed value engineering, working on the thermal model to optimise the insulation specification and meet the requirements of the Building Regulations.”
Based on the experience of previous ExtraCare projects, Vistry Partnerships West Midlands engaged Darren Evans for other essential compliance services. A Low and Zero Carbon (LZC) feasibility report, for example, looked at whether solar photovoltaics or other renewable technology could support carbon reductions on the scheme.
“Most services were briefed in from the start,” said Michael Brogden of Darren Evans. “Getting us involved on a project at the earliest possible stage meant we could make sure everything was accounted for, avoiding costly design changes later on.”
Psi value calculations assessed the thermal performance of junction details in the building fabric. The SAP and SBEM methodologies penalise specifications where the actual performance of thermal bridging details is not entered into the software.
Calculating the details not only avoided adding insulation elsewhere as a compensatory approach, it meant that the constructed details on site would reduce excessive heat loss, creating a more comfortable internal environment for residents.
A thermal comfort model, or overheating assessment, was also carried out to ensure the indoor temperature would not exceed a comfortable limit for the occupants. Credits for this were claimed as part of the BREEAM assessment.
Towards the end of the project, commercial and residential air testing was also carried out by Darren Evans. “This service was added later on. It was easier to arrange through us when we were effectively acting as a ‘one stop shop’ for sustainability services,” added Michael Brogden.
Late on in the project, the NHBC’s Building Control Service identified an issue with the construction of a junction detail in the ground floor area.
“The main challenge that Darren Evans helped us with was our bespoke facade construction,” said Matthew Curry. “NHBC said that the junction detail didn’t comply with their standards, but Darren Evans demonstrated that the detailing met the requirements, even though the design wasn’t explicitly covered by the wording of the standards.”
“The Building Control Service asked for the junction detail to be redone,” said Michael Brogden. “This would have meant taking off the brickwork and changing the detail. We carried out a surface condensation check and liaised directly with NHBC to resolve the issue. By showing that the construction on site didn’t need to be changed we helped to save around £50,000 in extra costs.”
A requirement of the contract between ExtraCare Charitable Trust and Vistry Partnerships West Midlands was that the Solihull scheme achieve a Very Good rating in an assessment against the BREEAM New Construction technical standard.
A BREEAM assessment adopts a wider definition of sustainability than just meeting the energy performance requirements of the Building Regulations. The commercial and residential aspects of the scheme were assessed together, so it was important to make sure that changing something in one area didn’t negatively affect another area of the assessment.
As Michael Brogden explained: “We carried out a BREEAM Pre-Assessment, which looks at previous projects. Based on other ExtraCare schemes we assumed credits would be available under the Ene01 energy category. When we finished the SAP and SBEM compliance modelling, however, we discovered that the specification constraints meant there were no credits to be claimed. It was a surprise!”
Matthew Curry agreed that the assessment was not straightforward. “The project was a challenge from the start. Larger sites have more space for landscaping, meaning it’s possible to claim credits for Ecology. There was hardly any landscaping on this site, so it was very close as to whether we could get the credits for the assessment overall. Michael and his team worked as hard as possible to get all the credits possible.”
“We had to be extra supportive through our BREEAM Accredited Professional service to get the final rating,” said Michael. “Some lateral thinking meant we were able to gather evidence that isn’t usually required. For example, by obtaining confirmations that pre-demolition audits were not required, we were able to claim additional credits in the Waste category.”
About Darren Evans
At Darren Evans, we work with you to create buildings and spaces that are more sustainable and energy efficient, creating comfortable environments in which people can be the best version of themselves.
Using our in-depth knowledge of building regulations and current technology, we can provide a range of services and solutions that are tailored to the needs of the project. We can work with you from setting the design brief through to completion on site, analysing and quantifying carbon and energy reductions to achieve your compliance and assessment goals.
To find out more about exceeding energy performance and sustainability requirements without excessive costs, contact us.