Signing up to a single contract for the supply and construction of the shell of your new home can make it easier to manage your budget and reduce stress, says Mike Hardwick

Mike Hardwick

MBC Timber Frame provided the kit and insulated foundations for this 230m2 Passivhausstandard self build project, including assuming responsibility for the airtightness of the finished shell

ALISTAIR NICHOLLS

Choosing the best way to deliver your project – ie how the scheme will be organised on the ground – often comes down to your budget. If you’re lucky enough to have plenty of spending power, it can make sense to put the onus on your builder or package house supplier to complete the work on a turnkey or custom build model. This will remove some of the stress and uncertainty for you, but the level of responsibility (aka the risk) they’re taking on will increase the costs. At the other end of the scale, those working with a tight budget many be tempted to save money by self project managing the scheme; ie hiring and coordinating the individual trades (and possibly buying in materials) themselves.

Somewhere in between these points is a sweet spot that works very effectively for many self builders, whereby the experts take on the hard bits of constructing the foundations, facilitating essential services and building the superstructure correctly to wind and watertight stage. This leaves you to simply manage the follow-on trades up to completion. This is known as shell building, and this month I’m looking at whether it could work for your project.

Building routes & risk

In all of the models, the overriding factor driving costs is risk. Under a turnkey arrangement, you get to pick the design and the builder delivers it to your specification – so they take on the risk of the construction process and will be expected to address any problems that arise. Assuming they’ve been hired on a fixed-price contract, they’ll have factored these risks on top of their project margin, which is why it costs more (especially on complex projects). The same principle applies if you’re working with a custom build developer: you agree the price, and that’s what you should end up paying.