CASE STUDY 3: Norbury Court, Staffordshire
Project brief: To be affordable and insulation. U-value of 0.20W/ sq unit extra in terms of build costs
sustainable with the hope that m K to meet the requirements of code
they would make a real difference level 3
to people’s lives and the local Floor: Proprietary concrete beam
community construction with polystyrene Sales value: About £135,000
infill and concrete screed. U-value or c.£1,688 per square metre
Development type: Nine terraced 0.21W/ sq m K compared to sales prices in the
units – seven three bedroom local area for existing stock of about
houses, one two-bedroom house Windows/doors: Double glazed, £125,000 or £1,563 per square
and one three-bedroom dormer low-e windows U-value of 1.20W/ metre
bungalow sq m K. Doors average U-value was
2.0W/ sq m K. Lessons learnt:
Build system: Factory fabricated • Use a good Code for Sustainable
timber frame construction with Air-permeability: The final air- Homes assessor and work with
particle board sheathing and brick permeability tested was 5.63 cu them from the start of the project
cladding m /@50pa for the first complete • Achieving code level 3 or above
dwelling means extra costs for renewable
Key sustainability features: Solar associated with the installation of energy technologies such as solar
thermal water heating, passive solar Insulation: Phenolic foam was the renewable energy systems and thermal water heating
design, low flow rate sanitary ware, injected into the external wall panel energy reduction measures • Not all renewable energy
rainwater recycling for garden, low void, supplemented with cut block • Meeting the low water use technologies will be appropriate for
energy lighting foam insulation in remaining sanitaryware criteria because the all sites
voids that could not be filled in supply chains for the equipment • Supply chains for some items
External fabric: Timber frame with this manner. The floors were were not adequately established at required to achieve code level 3
cement particle board sheathing constructed from a concrete beam the time of construction and above are sometimes still in
and phenolic foam insulation. system using polystyrene infill with development
U-value of 0.29W/ sq m K concrete screed Build costs: £950 per square metre,
excluding land costs and fees. Buyer/occupant feedback: All
Roof: Timber frame with timber Key problems: The developer estimated that the positive, with lower energy and
strand board and cut block foam • Site construction complications development cost about £7,500 per water bills reported
CASE STUDY 4: Mid-Street, South Nutfield, Surrey
Air-permeability: Design air- efficiency before drafting initial
permeability test targets were designs
3 cu m/h@50pa. Final tests provided • Construction details need to
results of 4.9 cu m/h@50pa be produced early in the design
process – remedial work is not as
Insulation: The SIPS system has effective as achieving low levels of air-
a sandwich of mineral wool and permeability on the first attempt
expanded polystyrene insulation • Mechanical Ventilation with Heat
Recovery can offer key advantages
Key problems: The biomass boiler in reducing energy requirements if
needs maintenance or attention correctly specified and installed
roughly every one to two weeks, plus • Local planning constraints may
Project brief: Initially planned to be FSC timber, and MVHR six-monthly servicing. This has created limit the available design options
code level 3, the scheme went on a series of additional call outs to • For small dwellings in rural
to become the first publicly funded External fabric: Structural Insulated service the boiler, causing significantly locations wood pellet boilers can be
social housing development in the Panel System (SIPS) with 50mm of greater maintenance costs an attractive option
UK to achieve code level 5 external insulation. U-value of 0.14W/ • Shared heating systems can be a
sq m K Build costs: About £1,850 per square practical and cost-effective solution
Development type: Two two- metre, excluding land costs and fees • A good relationship and
bedroom flats Roof: Timber frame with concrete – an uplift of about 20 per cent over understanding with the site manager
tiles and 400mm mineral wool standard build costs is necessary for a design to be
Build system: Structural Insulated insulation. U-value of 0.13W/sq m K realised
Panel System (SIPS) and beam-and- Sales value: Between £175,000 to • Heating, ventilation and renewable
block flooring with mineral wool and Floor: Beam-and-block with £200,000, or c. £2,857 per square energy systems specified in a project
expanded polystyrene insulation additional 75mm insulation. U-value metre, roughly equal to or above sale need to be demonstrated to the
0.14W/sq m K values for equivalent properties in the occupants. Clear written guidance on
Key sustainability features: Passive local area their use also needs to be provided
solar design, low flow rate sanitary Windows/doors: Windows were triple-
ware, rainwater recycling, low energy glazed, low–e windows uPVC. U-value Lessons learnt: Buyer/occupant feedback: Generally
lighting, PV array, biomass pellet of 0.80W/ sq m K. Doors were fully • It is important to involve a code satisfied but the erratic working of the
boiler, low energy rated white goods, insulated. U-value of 1.2W/ sq m K assessor with experience in energy boiler caused irritation
30 CIBSE Journal August 2009 www.cibsejournal.com
CIBSEaug09 pp26-31 Homes.indd 30 23/7/09 14:53:38
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