From accidental landlords to our first self build home development project UK

From accidental landlords to our first development project

HW Property's UK self build home case study

After becoming accidental landlords, we started to see property differently.

What started as circumstance gradually became intention. We had learned through refurbishment, through managing a rental ourselves, and through navigating planning processes for extensions.

So, when an opportunity presented itself to think bigger - not just about improving a house, but about a the possibility of a self build home, we were ready to explore it.

This is the story of our first self build home development in the UK – a three-bedroom detached home arranged over three floors.

Where it began

This project didn’t begin with the intention of becoming developers.

We’d bought a modest three-bedroom semi as our new home. We’d moved to allow Dan’s mum to live closer to us, but it took time to find something suitable in the area we wanted. Nothing felt quite right. So, like many buyers, we widened the scope and made a few concessions.

What caught our attention wasn’t the house itself, it was the garden and its potential. Proportionally large for the plot, it immediately sparked the idea of extending the kitchen and living space.

We started with a single rear extension to improve the downstairs layout. During that process, our builder at the time floated a bigger idea: rather than extending further, could we potentially secure planning permission for a separate dwelling at the side?

That idea was a revelation to us, but we parked it for a couple of years as work, life and becoming parents understandably took priority. But the thought never quite went away. Eventually, we decided to explore it properly.

Testing the idea

After some serious consideration, we went through a pre-planning process to assess viability. The response was positive, so we progressed to a full planning application and were successful.

It wasn’t without friction. Some neighbours were supportive, others less so. There were clipboard rounds and objection conversations. But ultimately, planning was granted.

Working with a friend who is an architect, we then developed the detailed design drawings. From pre-planning to breaking ground took nearly two years - juggling careers, parenting and life alongside a development project is not a fast process.

We also had to secure a self-build mortgage, which was a learning curve in itself. The amount of documentation, cost breakdowns, staged payment schedules and technical detail required was substantial. Running the project ourselves meant we needed to understand everything.

With a mixture of excitement and the need to keep builder schedules aligned, we began some early works before the finance was fully in place. That led to a few uncomfortable months juggling supplier payments and timelines. It became tighter than we would have liked at one stage, but fortunately we managed to get everything over the line.

By March 2022, we finally had spades in the ground.

Preparation and early challenges

Before building could begin, we had to:

• Demolish the side garage

• Carry out internal works to the existing property

• Build brick outhouses for both properties for additional storage

• Split the property title (We learned that the new title couldn’t have the same people on as the existing one, so only one of us could be on the new-build title)

• Undertake drainage testing and soakaway calculations

The drainage testing required digging an enormous hole in the garden to measure ground absorption. The resulting soakaway alone was so substantial that we needed a tractor to install it.

We also made a significant design change during this stage, switching from gas central heating to an air source heat pump with underfloor heating. This meant rethinking utilities and slab preparation, but we believe it was the right long-term decision.

All of this planning phase happened in the backdrop of COVID, supply chain issues and rising material prices.

The build: learning as we went

Dan’s close friend Matt, who runs his own building company, agreed to take on the project. While he had delivered large extensions and renovations before and was very knowledgeable, this was his first full new-build - so we were learning together.

In fact, two years earlier, Dan had jokingly bought Matt a brick trowel for his 40th birthday and told him he’d build us a house one day. At the time, he didn’t really believe it.

Foundations

We knew the ground was unstable from our earlier extension, so piling was expected. But the scale surprised us.

The new house required 23 foundation piles, some going as deep as nine metres. At one stage during groundwork, the boundary wall began to collapse - just as next door were celebrating their own redevelopment with fish and chips. There was a brief but memorable moment of panic while emergency concrete was ordered, and the wall was shored up.

Structure and brickwork

Once we were out of the ground, things moved more quickly. There were still moments of stress though:

• A ground floor wall was 3cm out, testing beam tolerances. A quick call to the beam supplier confirmed that although 50mm bearing was available at each end, 10mm was structurally sufficient - panic over.

• Some brick deliveries didn’t match, so the whole lot had to be reordered

• Architectural and structural drawings required careful interpretation, particularly technical notations.

• Part M accessibility requirements were something we initially underestimated in importance

The brickwork moved quickly thanks to a brilliant (if occasionally window-forgetting) bricklayer.

We also had a crane complication when newly installed BT cables meant we couldn’t lift roof trusses in one go - forcing a manual workaround. The team had to separate all the trestles and manually lift them one by one onto the structure and then reassemble.

There were lighter moments too. Our daughter became a regular site visitor, fascinated by the process - and by the builder’s dog. And our cat Harry developed a habit of using sand deliveries as a personal litter tray, much to the builders’ amusement and frustration.

Completion and sign-off

Once complete, there were still processes to navigate:

• Building Regulations sign-off

• Final inspections and structural warranty documentation

• EPC certification

• A substantial VAT reclaim process

As a new build, the project qualified for zero-rated VAT, allowing us to reclaim the VAT paid on eligible costs. The process required meticulous documentation and strict compliance with HMRC guidelines. It took time to compile and submit, but we successfully reclaimed nearly £20,000.

The original build cost estimate was approximately £220,000 including contingency. Final costs came in at around £240,000, largely due to post-COVID material increases and supplier volatility. We learned quickly to bulk-buy materials where possible to mitigate further price rises.

The property was valued at £420,000 and ultimately sold for £380,000, delivering a strong uplift on build cost, reflecting disciplined budgeting and execution.

While we could have held out for a higher sale price, the project had always been intended as a stepping stone into further projects rather than a long-term hold. With mortgage rates rising sharply at the time, and the property sitting in our personal names rather than a company structure, retaining it didn’t align with our wider plans. Recycling capital and protecting margin supported our longer-term strategy more effectively.

What we learned

This was our first full self-build and development on this scale, and it taught us a significant amount. We learned:

• Planning takes longer than you think

• Finance processes are detailed and demanding – systems matter

• Ground conditions can change everything and often carry the greatest unknown risk.

• You must question drawings and interrogate every structural drawing notation

• Cash flow management is critical

• Prices can shift quickly - contingency really matters

• And above all, the relationships with your builder and contractors matter enormously

It wasn’t a smooth, linear process. There were challenges, unexpected issues and plenty of on-the-spot decisions, but each one deepened our understanding and strengthened our confidence.

But it proved that with the right preparation, resilience and long-term thinking, a project like this is possible while juggling work, parenting and life.

And for us, it marked the point where we stepped beyond refurbishment and into development. It gave us the confidence and systems to approach future projects - whether refurbishments, BRR opportunities or developments - with greater commercial understanding and experience.