The brief
Planning the extension
The clients needed a guest room, WC and storage in place of the existing conservatory. Layout options considered the garden, access and thermal performance before the design was agreed.
Fabric first
Performance and construction
SIP panels and continuous insulation form the building envelope, supported on ground-screw foundations. The table compares this project's wall, roof and floor build-ups with the conventional alternative considered during design.
| Element | Eco-extension | UK standard | Difference |
|---|---|---|---|
| External wall thermal performance | 0.14 W/m²K | 0.18 W/m²K maximum | 22% better than the wall requirement. |
| External wall thickness | 260 mm | 320–335 mm | 20% thinner than a standard brick-and-block cavity wall. |
| Roof | 0.13 W/m²K | 0.15 W/m²K maximum | 13% better than the roof requirement. |
| Floor | 0.15 W/m²K | 0.18 W/m²K maximum | 17% better than the floor requirement. |
| Overall performance | The eco-extension performs 17–18% better than the relevant UK standards. | ||
| Construction cost | The eco-extension costs 7% less than the standard equivalent construction. | ||
The transformation
From conservatory to extension
The render, windows and roof finishes relate to the existing house. These views show the original conservatory, the proposed design and the completed extension.
The result
The completed extension
The finished guest room has direct access to the garden, with a WC and storage incorporated into the layout. The photographs show the interior and the extension's relationship to the house.
The client’s experience
“Gate5 were very conscious of the environmental concerns we had with our garden and suggested the SIP panel build as a way of keeping within budget while still getting the space we needed.”Sarah & Mickey · Brislington, Bristol
Planning a home extension?
Tell us about the property, what you want to change and whether you need design, technical drawings or construction. We can discuss the next steps.