National Self Build & Renovation Centre Logo close Menu
Book Free Now

Damian & Claire Le Gresley

Damian & Claire recently completed an extension and re-modelling of their existing house in Wiltshire, using SIPs for the walls and roof to create their bespoke, modern & more energy-efficient home.

Could you tell us any interesting facts or remarkable features about your project?

We wanted to use a Structural Insulated Panel System (SIPs) to give us a water-tight shell quickly after the disruption of the demolition and steel work in the existing house, which had to be done before the extension was erected. We also knew that SIPs would give us a highly insulated and air-tight structure that would help minimise additional heating requirements.

Damian & Claire's Experience at the National Self Build & Renovation Centre

How many times have you visited The National Self Build and Renovation Centre before? 4-5 times.

What would you say is the most helpful feature or resource at the NSBRC? The talks which helped us learn a lot about relevant technologies and techniques, plus the ‘Ask the architect’ feature where we met Kevin Slack from Greenspace Architects who designed our extension.

Did you use any other exhibitors at the NSBRC? If so, who? ecoHaus Internorm, FMB, Nu-Heat and Velfac.

What did you enjoy most about your visit to the NSBRC? Having under one roof so much expertise to inspire us and help us make our home aspirations a reality.

Would you recommend the NSBRC to a friend, and if so, what aspects of the Centre would you recommend and why? Yes, we have recommended it - the show talks have been inspirational and sustainability is a constant theme across the exhibition.

Existing Drawings

All proposed drawings

3D Drawings

Information compiled & published in March 2023.

Damian & Claire's Self Build Experience

What first inspired you to undertake project – what did you hope to achieve? To replace our aging cold/hot conservatory with a year-round space that could be the main living room, and with a bigger kitchen, but much more in contact with our view and garden.

We wanted to do all this as sustainably as possible, to continue the low energy improvements we had already made over 15 years. The house’s orientation and layout still caused poor natural light to much of the ground floor and the design process sought to address this. We had also realised the house was under-ventilated after previous improvements, so we took the opportunity to upgrade to a whole house MHVR system during the remodel and install solar PV.


What was the cost & size of the land? We already owned the land in our back garden.


Did you have any issues getting your planning permission granted or with building control? No, our architect and main contractor ensured these were plain sailing.


Why did you choose your method of construction? For sustainability we wanted to use a modern method and of construction and having also researched insulated concrete formwork and timber frame we favoured structural insulated panels. SIPs seemed most practical given the poor access to the rear of our property, the unusual shape of the footprint and roof plus, it being fabricated off-site, it would deliver the airtight and well-insulated walls and roof quickly. Eventually we found a SIPs company, Bentley SIP Systems, who were willing to take on our relatively small, “awkward” project and they designed, manufactured, delivered and erected the superstructure.


Did you use a project manager, or did you choose to self project manage? We directly contracted with the architect, SIPs company and structural engineer and also ordered doors, roof windows, cladding, and the heating and ventilation systems. JMW Carpentry & Builders were our main contractors and project managers including groundworks, demolition, masonry, steelwork, carpentry, plumbing, electrics, roofing, flooring and plastering. We were hands-on ourselves where we could; installing the MVHR system, laying underfloor heating pipework, decorating, and applying airtight tape everywhere.


What was your budget and were you able to stick to it? We were hoping to spend under £240k but ended up spending £265k.


If you didn’t stick to your budget, what was the main reason for the overspend? Materials prices increased rapidly from late 2021 when we were estimating the project, to spring/summer 2022, when the majority of materials were actually purchased. We helped offset some of the increases by re-using materials such as the bricks to rebuild the rear wall which we cleaned of mortar and selling salvaged items on eBay.


What is the value of the property now? Unknown, but we have no plans to move so have not had a valuation. We hope to have added similar value to our property as we spent on the works.


Did you reclaim the VAT, and if so, how much were you able to reclaim? No, unfortunately as it was an extension and re-modelling project it was not possible to reclaim any VAT.


What aspects of the process did you find stressful? Synchronising between our SIP company, sliding door company and our main builders was quite stressful as it was a complex design to lay out onsite and we had to align the long lead times of the panels and door with the shorter but less predictable lead times of groundworks and bricklaying. We managed to get the timings and foundations layout correct but when the door opening was measured just before fitting it was too small due to a misunderstanding on sill heights. Fortunately, our carpenter saved the day by trimming down the glulam above the doorway to allow the door to fit perfectly – it made us glad we had opted for glulams rather than steels in the extension structure!


Do you have any tips on how to avoid the pitfalls you encountered? Our tips are to check and double-check that your contractors are on the same page, and speaking the same language, and dimensions understood and agreed by all parties. Don’t underestimate the time and care it takes not to trip up when the jigsaw pieces are being made in parallel and by different people away from and on the site.


What did you find most enjoyable about working on your project? Problem solving – working with all our trades to link the old and new areas of the house seamlessly. It was satisfying to be able to work on some parts of the projects ourselves, in partnership with the professionals.


What is one of your favourite features about your project? The bright, colourful, social kitchen/dining/lounging space with huge sliding doors onto the garden and tree-filled panorama.


How did you tailor your home to suit your lifestyle? We integrated smart lighting, electric blinds and audio-visual systems, and carefully designed our new kitchen island with induction hob, extractor, boiling water tap and ergonomic storage and seating.


Is there a possibility you would ever undertake another project in the future? Probably nothing on this scale on this plot - it’s a forever home for us. We do want to do some internal improvements to the upstairs perhaps also making the switch to a heat pump at that time.


What would your top tip be for other NSBRC Visitors about to embark on their first self build or home improvement journey?

Do your research and immerse yourself in all the possibilities - go to the shows and listen to the experts! Employ people you can get on with and who are as passionate about your build and your expectations for it as you are.