Appendix A: Cost Breakdown
211. The developed costs are based on the expert view of Currie & Brown’s cost specialists, drawing on evidence from their internal cost datasets, recent published cost data and information provided by suppliers.
212. The cost analysis is intended to reflect typical national costs from Q1 2020 that might be incurred by a public or private developer with reasonably efficient supply chain, design development and construction processes. However, costs incurred by individual organisations will vary according to their design, procurement strategies, the location of their activity (e.g. costs will be higher in more remote locations such as the Western Isles than in the Central Belt) and the detail of their project. These variations design, location and delivery method could result in a cost range of +/- c.30% or more (see Section 0). Notwithstanding these variations, the proportional uplifts associated with moving from one specification to another are likely to be relatively similar across different market segments.
213. To provide context to the cost variations assessed in the study an indicative overall build cost (£ per m2) for each building archetype was estimated using Currie & Brown internal data. This figure is indicative of the level of cost that might be expected for a building built in accordance with the requirements of Section 6 2015. The build cost should be taken as indicative only as it is sensitive to a wide range of design and specification variables in addition to the economies of scale and regional variations discussed previously.
214. Base costs for future years are those for the 2020 price year, and subject to adjustments for learning for technologies that have not yet reached a mature market position. It should be noted that construction costs can vary considerably and rapidly with market conditions, particularly where activity levels result in a change in the availability of skills and materials. In these situations, it is not unusual to see quite large (several percentage points) change in overall costs over a period of months.
215. Table 89 includes details of the cost information used for each specification option, including any variations between building type, costs are only shown for those specifications that vary between the considered specification options.
|Element||Specification||Unit||New cost (£ per unit)||Annual maintenance costs (£ per unit)*||Average life expectancy|
|External Wall – steel framed construction with mineral wool||0.23 W/m².K||m²||£365||£0||60|
|External Wall – masonry construction with mineral wool||0.23 W/m².K||m²||£235||£0||60|
|Ground / Exposed Floor (concrete slab, rigid insulation and screed)||0.22 W/m².K||m²||£61-70||£0||60|
|Raised exposed Floor (concrete deck, rigid insulation and screed)||0.20 W/m².K||m²||£42||£0||60|
|Flat roof – warm deck||0.18 W/m².K||m²||£214||£0||60|
|Warehouse roof||0.18 W/m².K||m²||£53||£0||60|
|Windows uPVC||1.8 W/m².K||m²||£570||£0||30|
|Gas boiler (incl flue, pump and controls)||91%||kW||£40||£0.5||15|
|Biomass boiler||incl flue and fuel store||kW||£598||£0.6||15|
|Buffer tank||10 l per kW||Ltr||£1||£0||15|
|Radiant gas panels||m² GIFA||£22||£0||20|
|Radiators||Low temp||m² GIFA||£27||£0||20|
|Lighting - office||60 Lln/W||m² GIFA||£59||£0||15|
|Lighting - warehouse||60 Lln/W||m² GIFA||£53||£0||15|
|Lighting - display||22 Lln/W||m² lit area||£45||£0||15|
|Display light controls||Time switch||m² lit area||£2.5||£0||20|
|Roof mounted - photovoltaic panels||Variable costs for systems >4kWp||Per kWp installed||£1,100||£12||25|
|AHU Heat recovery unit||70% efficient||m³/s||£7000||£0.70||25|