Planning consent for a certified oak frame Passivhaus in Worcestershire

Written by David Bryan – a Certified Passive House Consultant

 

Andrew and Linda Burnett expressed an interest in Passivhaus at a very early stage of the design process, following their initial discussions with Tim Crump at an NEC exhibition back in 2015.

They were determined to create a build that met the Passivhaus standards, so with this in mind, we were able to work with them to develop their design holistically. The Burnetts were keen to have an upside-down interior layout to make the best views of their site, with the main living areas and an en-suite master bedroom which benefits from a walk-in dressing room, upstairs. Thinking of the future, the requirement to have space for a lift was also planned into their final design.

There was also the consideration that Andrew and Linda may want to operate a small Bed and Breakfast, so each bedroom on the ground floor was to be provided with an en-suite, rather than share a bathroom.

A drawing to show the front elevation of our clients' home, designed by David Bryan

Recognising the potential of the plot

We initially engaged with Andrew and Linda in 2015 on another site in Worcestershire, which turned out to be unsuitable for their needs. A number of non-starting sites later, Andrew and Linda found a plot, then known as ‘Redwood’.

The plot is situated in the Malvern Hills Area of Outstanding Natural Beauty (AONB) and therefore comes under more scrutiny than normal due to it being classed as ‘designated land’ in legislation covering planning permission. This designation also covers National Parks, the Broads, Conservation Areas and World Heritage Sites, and is intended to further protect these areas from harmful development.

Andrew and Linda purchased the site with extant planning permission attached for a traditional cottage to replace the existing bungalow. When we first viewed the site, the bungalow had been demolished and foundations were laid for the cottage by the vendor. In terms of designing a Passivhaus, the orientation of the extant permission wasn’t ideal being north/south, with the majority of glazing on the east and west elevations.

This drawing captures the vision for the rear elevation

The architectural design and planning application process

The initial requirement was to base the Burnetts’ new oak frame home design on having a largely south-facing principal façade to make best use of the solar gain, but we were also aware of incorporating aspects from the carefully considered brief I’d been given by Andrew and Linda, in terms of the internal rooms and their approximate positions.

Our vision for the building was to create something to look reasonably traditional but with a contemporary edge, without being overtly ‘boxy’ as is some people’s idea of a Passivhaus design. Andrew and Linda had a similar wish, which always makes the dialogue over concepts much easier!

The new proposal was both higher with more mass than the extant permission but was deemed allowable by the planning officer. This was due to the mitigating factors of the additional insulation, the denser wall and roof thicknesses and the high-level of sustainability offered by a Passivhaus dwelling.

The project included our internal post-and-beam structural oak frame, encapsulated with an enhanced version of our WrightWall and WrightRoof Natural system. This includes recycled cellulose wood-fibre insulation with an additional 60mm of wood fibre insulation externally (Gutex Ultratherm) to minimise cold bridging and provide the even further enhanced U-value performance for Passivhaus. Airtightness is an important consideration for all our builds; for our WrightWall Natural panels, the internal finish (behind the plasterboard and service void) is an airtight Smartply ProPassiv board, which is carefully taped to ensure exceptional airtightness, as born out in the results below!

Here is a photograph of the front elevation, featuring red bricks and bonding to remain sympathetic to the surroundings

Achieving Passivhaus certification

Construction began in April 2018 and was completed in 11 months. Andrew and Linda’s new oak framed home was assessed by WARM: Low Energy Building Practice, and passed the requirements of the Passive House Institute, being awarded the classification of Certified Passive House Classic on 16th September 2019. The Burnetts’ home achieved an overall space heating requirement of 13 kWh per m2 of living space per year (the maximum allowable being 15). A fantastic result all round!

 

Here at Oakwrights, we strive for accurate details and this system is ideally suited to the intricacies of using the Passive House Planning Package (PHPP) and the myriad of information that is included within it. Additionally, having control of both the architectural design, and the technical Passivhaus analysis allows for a deeper understanding of the cause and effect process of alterations to the design.

Within our Architectural Design team, we have in-house Passivhaus specialists: Dr Pegah Behinaein, a Certified Passive House Consultant, and Craig Alexander, a Chartered Architect, to advise and help you to evolve your ideas for your Passivhaus design. Please call 01432 353 353 or email enquiries@oakwrights.co.uk to discuss your ideas with us.

 

The team behind the design of this oak frame project:

  • Business Development Manager: Craig Holden
  • Architectural design: David Bryan
  • Planning and Building Regulations: David Bryan
  • Frame design: Sarah Connelly
  • Encapsulation design: Steve Laws
  • Estimating: Ellie Jude
  • Project Manager: Chris Mullis

 

Would you like to learn more about the Burnetts’ home building journey and unique Bed and Breakfast? Please see a link to their case study below.

Architecture, Encapsulation
29 Mar 2021

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