What’s the difference between self-build vs custom build?


If you are looking to build your own home, there are generally two ways that you can go about doing so; self-build, or custom build. Most of us are familiar with self-build through Grand Designs, but what about custom build?


What’s the difference?

Put very simply, self-build is when you take on all the risks yourself. You also have the final say on everything.


With custom build homes, some of the development has been done already, which reduces your risk, but it does mean that some of the choices will have already been made.


Let’s look at both in more detail.



In a self-build project, as the name suggests, you are going it on your own. From finding the plot of land for sale, getting planning permission, to hiring architects, builders and other contractors. If anything goes wrong (and if you’re a Grand Designs fan, you’ll know that happens a lot!), then you are responsible for sorting it out.


A common misconception is that creating self-build housing means that you have to learn how to drive a digger and plumb a sink in. In fact only 8% of people* actually do some of the work themselves. Most self-builders either do the project management (and hire the entire team) or pay a company to do it all for them.



Custom build

Custom build comes in many forms, but, depending on where you are in the country, the main routes are the following:

  • A serviced plot
    This is where the developer has bought a larger plot of land and carved it into smaller plots. They will have run drains and other services to the plot along with roads and you will then take it on from there. The plots will have planning permission for either a detailed design or an outline design.
    If it is an outline design, you can use your own architect to design the rest of the home. You will probably have to adhere to a design code, eg., homes of a particular size, height or look. Make sure that you don’t buy a plot of land without planning permission unless you have had expert advice. Many people have lost thousands of pounds thinking that a plot of land in agricultural green belt can become a home. It very rarely can!
    You can rely on Custom builder developers who are members of NaCSBA as they have to adhere to a Code of practice and selling a plot with hope value is at best highly unethical and at worst illegal.
  • Shells
    This is where the developer has build a watertight structure. From the outside, a custom build shell will look finished. It’s only when you walk through the front door that you will find all of the inside missing!
    If you’ve ever witnessed a large renovation project, you’ll know that they often start with ripping all of the inside out to start again. A shell is essentially the same as that. There are also ‘warm shells’ where the developer has put some services in, eg. heating and electrical circuits. This leaves you with less to do, but warm shells will cost more than a standard shell.
  • Turnkey
    This means that you order what you want (within the menu of choices that the custom builder offers) and the developer delivers it. It’s very similar to ordering a new car. You choose colours, layouts, types of kitchen etc. This is a very convenient way to buy and self-build a house, but it will cost more than either of the other routes and your choices may be somewhat limited.

At Unboxed Homes, we specialise in custom build homes in London and the South East and we build shells. This means that we will have sourced and bought the land, got planning permission, and all other consents like party wall awards. We will also manage some of the trickier and riskier parts of the build like ground-works, foundations, and the structure.

So self-build vs custom build – what’s better?

The answer is of course, as always, it depends.
How much risk do you want to take?

Self-build tends to be best for people who have a healthy risk appetite, lots of time, or are happy to pay someone to do it for them. It tends to suit property professionals who know what they are doing, or people who want total control.


It’s also the best route for people who want to save the most amount of money on their new home as long as they don’t have a time constraint. It’s not uncommon for people who do a lot themselves to take ten years to build their own home.


Custom build helps clear some of these hurdles and opens up the path to building your own home to a wider group, which is why we think that the best option is to build our homes as shells.


It means our purchasers have the freedom and flexibility to choose layouts, finishes, and specifications, and create their own self-build designs, but takes away a lot of the risk, and also saves them time.


Our MD Gus spoke to SelfBuild & Design magazine for their March 2020 issue about the pros and cons of each route, and gives some good practical tips of how to go about building your own house.

If you’re looking for a plot of land:

“Serviced plots are a good option for people looking to build their own home from scratch but can’t find the land and don’t want the pain or risk of getting planning permission.”

And if you don’t have a lot of time:

“Time-poor buyers are probably best advised to consider a shell or a turnkey as these will be the quickest to complete. For those who don’t have a tight deadline, but don’t have much time day-to-day, hiring a builder or an independent project manager to deliver a self or custom build on a serviced plot is a good option, but this will cost more. ”

Read more about Gus’ thoughts below.

Have any more questions or comments? Let us know below!


* Source: NaCSBA research

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