Treehouse ProjectSEED Homes at a glance

A simple way to build sustainable and affordable houses.

We have developed a way of using native soft wood to produce super-insulated structural panels. We can build quickly and with low embodied energy by using sustainable, local materials. We have now built a full size prototype, a 3 bedroom house and a school boarding house.

Our experience building the 3 bedroom house allows us to make the following claims:

  • Carbon emissions are 73% lower than for a standard house
  • It uses 50 % less water.
  • Most of the materials are locally sourced and 98% of them can be recycled.
  • Minimal synthetics, chemicals and adhesives used.
  • Manufacturing and construction has all used local labour.
  • This is still all for the Local Govt. price of an affordable home.

Certification and Standards:

Code for Sustainable Homes: Level 4 (69 points TBC)
BS standard: Currently in testing
Building Regulations: Exceeded.


Insulated wall panel: U Value 0.13 W/m²k
Glazing: U value 1.8 W/m²k    
Energy use: Predicted SAP rating 81 (out of 100, very good!)
Water use:

Grey water from rainwater harvesting throughout
74 litres per person (50% better than Building Regulations)

Heating: Underfloor heating from District Bio-mass system
Ventilation: All natural (non-mechanical stack)
Recyclability: 98%
Carbon Footprint: -16 tonnes
Dwelling emission rate: 72.91% better than Building Regulations



Timber: Welsh Spruce C 16 Grade dried to 20% moisture
Insulation: Warmcell 500 recycled cellulose – 60kg p/m3, manufactured in Wales
Steel nail plates: Wolf System, Coventry
Base: Insulated Cemex eco-concrete floor
Roo: Corus 32/1000 profiled steel
Glazing: Pilkington Low E double glazed K units
Window & Door Frames: Welsh FSC softwood.


Construction time:

Fabrication: Fforest Timber Engineering, Swansea: 2 days
Groundworks: Brownfield site works: 12 weeks
Erection of panels: 2 days
Fitting out and completion: 20 weeks

Full building price: < £1,300 p/m2

 -- SEED Homes, February 2010