the penthouse specification & prices

specifications

  Penthouse 150 Penthouse 100 Bdg regs standards¹ Typical Garden Office/Room
  Thickness U value² Wm-²/K Thickness U value² Wm-²/K U value² Wm-²/K Thickness U value² Wm-²/K
Roof insulation 153mm 0.14 128mm 0.17 0.16 - 0.25 45mm 0.57
Wall insulation 128mm 0.17 78mm 0.28 0.30 - 0.35 45mm 0.57
Floor insulation 100mm 0.22 100mm 0.22 0.22 - 0.25 0 1.20
Windows/doors - 1.15 pane - 1.15 pane 1.8 - 2.0 - -
  - 1.80 frame - 1.80 frame - - 1.90 frame

¹ Building Regulations Part L 2002
² U value calculation: BRE U value calculation version 1.08. Calculation method: BS EN ISO 6946

insulation

Insulation is HCFC free Polyurethane foam zero rated for ozone depletion. For a garden office of approximately 10m², the difference in heating costs between the Penthouse 100 and Penthouse 150 garden offices will be approximately £30 a year. The difference in heating costs between the Penthouse 150 and a typical garden office specification will be approximately £200 a year. All figures depend on set temperature and fuel source. Figures based on set temperature of 19°C and electric underfloor heating.

windows and doors

The standard specification for windows and doors is double glazing of 4mm separated by a 16mm, Argon filled gap. A heat reflecting coating is used on the inner surface of the glass. Safety glass is used where Building Regulations demand it and can be used elsewhere. Triple as well as double glazed windows and doors are also now available.

heating

Heating options are unlimited but we recommend electric underfloor heating. Thermostatically controlled and programmable, this system provides a very even heat and ensures the office is warm first thing in the morning but doesn't waste energy heating the space during the evenings and weekends.

surfaces and finishes

External cladding choices are many and varied but would typically be 18mm Cedar, Larch or Douglas Fir fitted with stainless steel screws to prevent unsightly staining. Rendered external surfaces are also possible to match existing buildings. Internal surface finishes include plasterboard or Oriented Strand Board finished with paint or plaster. Almost any type of floor covering can be fitted. Please call for options and prices.

prices

Penthouse 150 Penthouse 100
Internal area (m²) Pitched roof Flat roof Pitched roof Flat roof
Small 4.25 £7,790 £7,290 £6,825 -
Medium 10.5 £13,240 £12,420 £11,820 £11,170
Large 19.0 £20,900 £19,400 £17,980 £16,740

All prices exclude VAT. Prices include foundations but exclude electrical plus other connections from the house. Delivery and installation included within Hertfordshire, Essex, Bedfordshire and Buckinghamshire.