Building your own home is one of the most rewarding projects you can take on, and Cornwall is a place where plenty of people dream of doing it. It's also a project with a lot of moving parts: land, planning, design, finance, Building Regulations and the build itself. This guide walks through the self-build process step by step, with the Cornwall-specific points worth knowing before you commit to a plot.
What counts as a self-build?
"Self-build" covers more than laying every block yourself. Most self-builders in Cornwall commission a home rather than physically build it. Common routes include:
Main contractor route. You buy the plot and get the design and planning in place, then appoint one builder to deliver the whole house.
Project-managed route. You (or a project manager) appoint and coordinate individual trades. This can save money but takes much more time and carries more risk.
Custom build. A developer provides a serviced plot and you choose or adapt the design.
The route you choose affects your budget, your workload and how your mortgage lender and warranty provider see the project.
Step 1: Find and assess a plot
Plots in Cornwall are in short supply, especially near the coast. When you find one, look beyond the view:
Planning status. Does it have outline or full planning permission, and what conditions are attached? A plot without permission is a gamble.
Access and services. Narrow lanes, visibility splays, and the cost of bringing in water, electricity and drainage can add a lot. Many rural plots have no mains sewer, so you may need a treatment plant.
Ground conditions. Sloping sites, rock, made ground and old mine workings all affect foundations. A mining search is sensible in many parts of Cornwall.
Designations. Plots in the Cornwall National Landscape (formerly the AONB) or a conservation area will face closer design scrutiny.
Getting a builder or surveyor to look at a plot before you buy can flag costly surprises early. Our groundworks and foundations work starts with exactly this kind of assessment.
Step 2: Design and planning permission
An architect or designer will turn your brief into drawings that suit the site and local planning policy. Cornwall Council will assess the application against the Cornwall Local Plan and any neighbourhood plan for the parish, which can include policies on design, size or occupancy. Pre-application advice from the council can be useful on less straightforward sites.
It's also worth joining Cornwall Council's self-build and custom housebuilding register, which councils use to understand local demand. For a wider overview of applications, see our guide to planning permission in Cornwall.
Step 3: Budget, finance and tax
As general guidance only, UK self-build costs often fall somewhere around £2,000 to £3,500 or more per square metre for the build itself, depending on specification, site and design. Coastal and rural Cornish sites can push costs up through access, groundworks and weather-proofing. On top of the build, allow for:
Plot purchase, legal fees and surveys
Design, structural engineering and planning fees
Building Control fees and a structural warranty
Service connections and drainage
A contingency of around 10 to 15 percent
Self-build mortgages usually release money in stages as the build progresses, so it helps to have a clear programme agreed with your builder.
Two tax points are worth checking early:
Community Infrastructure Levy (CIL). Cornwall charges CIL on new homes, but self-builders can usually claim an exemption. It must be applied for and confirmed before work starts on site, otherwise you can lose it.
VAT. Building a new home is generally zero-rated for VAT, and self-builders can reclaim eligible VAT on materials through HMRC's DIY housebuilders scheme. There are time limits for claims after completion, so keep every invoice.
These rules can change, so confirm the details with the council, HMRC or your accountant.
Step 4: Building Regulations and warranty
Planning permission and Building Regulations approval are separate. Your design will need Building Regulations approval covering structure, fire safety, energy efficiency, ventilation, drainage and more, through Cornwall Council's Building Control or a registered building control approver. Most lenders will also expect a structural warranty or an architect's certificate, so arrange this before you start.
Step 5: Choosing a builder and the build itself
The right builder makes the biggest difference to how smoothly a self-build goes. Look for:
Experience of new builds on similar sites
A clear, itemised quote and a written contract
A realistic programme that allows for Cornish winter weather
Good communication and a single point of contact
A typical build moves through groundworks and foundations, the structure and roof (getting it watertight), first fix services, plastering, second fix, and finishes. Our new builds in Cornwall page explains how we manage this, and our project management and QS services can help keep costs and trades on track. If you're interested in a low-energy home, see our sustainable building and eco homes page.
Self-build FAQs
How long does a self-build take in Cornwall?
It varies widely. Finding a plot and getting planning can take many months on its own. The build itself commonly takes around 9 to 18 months depending on size, method and weather.
Do I need planning permission for a self-build?
Yes. A new dwelling needs full planning permission (or reserved matters approval following outline permission) from Cornwall Council, plus Building Regulations approval.
Can I live on site in a caravan during the build?
Sometimes, but it may need permission of its own. Check with Cornwall Council before you rely on it.
Is a timber frame or block build better?
Both work well in Cornwall. Timber frame can be quicker to make watertight; masonry is familiar and robust. The best choice depends on your site, design, budget and energy goals.
Talk to us about your self-build
If you're weighing up a plot or getting ready to build, we're happy to talk it through. Call Cornish Building Company on 01208 816991 or get in touch through our contact page.
