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Can you break down the costs of a new build?
Can you break down the costs of self-building? What percentage should I allocate on each of the following build stages: foundations, drains and oversite; ground floor; second floor; the roof; first fix; plaster walls and ceilings; and second fix and finishings?
You are right to break the build up into six to seven stages. However, I would tend to put ground and second floors together into one stage, and to add an extra stage at the end to cover finishes and externals. Also, from a costing point of view, it’s not helpful to split electrics, plumbing and carpentry into first and second fix.
In reality, there is no ‘industry standard’ for breaking down build costs, but you won’t go far wrong if you work to a break down such as the following:
Groundworks and drainage: typically 15% (though it can be significantly more on difficult sites)
The shell, up to wallplate level: 30%
The roof structure and cover: 12-15%
Plumbing, heating and electrics: 12-15%
Plastering, wall finishes: 8-10%
Finishes (kitchens, floor covers, stairs, joinery plus externals): 20-25%
These proportions tend to keep in balance whatever the build size or quality. If you elect to build in timber frame or one of the other factory-built systems, you would place the supplied superstructure into a separate stage.
I don't think there are enough stages here: what about the cost of putting in gas, electric, water and data connections? These are not insubstantial. What about the cost of a driveway and other hard landscaping features like patios, paths and garden walls and fencing?
Also, although the other costs listed below don't usually fall under the heading of "construction costs", they are all tied up with getting the build done and are inescapable once you have bought the land, obtained planning permission and secured finance: what about building control inspections, your structural warranty (+ £5000 retained for two years in case of trouble), SAP and other design fees, sound transmission and air leakage testing, Phase 1 environmental surveys, a soil survey to guide the design of your foundations, an engineer's fees for any steelwork or if you're building on clay or near trees, and so on. These all add substantially to your "official" build costs and will quickly mount up and impact on your precious building funds, so you need to be prepared for them in your budgeting, otherwise you will find yourself running out of money and skimping when you get to the final crucial weeks of fitting-out.
2 answers
You are right to break the build up into six to seven stages. However, I would tend to put ground and second floors together into one stage, and to add an extra stage at the end to cover finishes and externals. Also, from a costing point of view, it’s not helpful to split electrics, plumbing and carpentry into first and second fix.
In reality, there is no ‘industry standard’ for breaking down build costs, but you won’t go far wrong if you work to a break down such as the following:
Groundworks and drainage: typically 15% (though it can be significantly more on difficult sites)
The shell, up to wallplate level: 30%
The roof structure and cover: 12-15%
Plumbing, heating and electrics: 12-15%
Plastering, wall finishes: 8-10%
Finishes (kitchens, floor covers, stairs, joinery plus externals): 20-25%
These proportions tend to keep in balance whatever the build size or quality. If you elect to build in timber frame or one of the other factory-built systems, you would place the supplied superstructure into a separate stage.
I don't think there are enough stages here: what about the cost of putting in gas, electric, water and data connections? These are not insubstantial. What about the cost of a driveway and other hard landscaping features like patios, paths and garden walls and fencing?
Also, although the other costs listed below don't usually fall under the heading of "construction costs", they are all tied up with getting the build done and are inescapable once you have bought the land, obtained planning permission and secured finance: what about building control inspections, your structural warranty (+ £5000 retained for two years in case of trouble), SAP and other design fees, sound transmission and air leakage testing, Phase 1 environmental surveys, a soil survey to guide the design of your foundations, an engineer's fees for any steelwork or if you're building on clay or near trees, and so on. These all add substantially to your "official" build costs and will quickly mount up and impact on your precious building funds, so you need to be prepared for them in your budgeting, otherwise you will find yourself running out of money and skimping when you get to the final crucial weeks of fitting-out.