Join MTBO
[49] The Fixed-Price Bournemouth Penthouse
Map data: Google, SIO, NOAA, U.S. Navy, NGA, GEBCO - Image: Landsat / Copernicus

Location

  • South West England

Build Start

  • 2005

Architect

  • Rod Mathieson

Total Floor Area

  • 188 m²
  • [Source: EPC ]
A redundant rooftop solarium gave James and Katrin Gray access to a coastal plot few self-builders could find. But an unresolved brief, constant variations and the decision to build without a temporary roof turned a 16-week programme into ten months of disruption, showing how quickly a fixed-price contract loses its protection when the design keeps changing.

Site Purchase Price

  • £ 695,800

Site Area

  • 1,669m²

Site Cost Per m²

  • £ 417

Initial Budget

  • £ 314,400

Total Spend

  • £ 1,167,300

Budget Overspend

  • 49.97%

Cost Per m²

  • £ 2,508

Site Coverage

  • 19.81%

Plot Ratio

  • 11.26%

Land V Build Costs

Land 60%
Build 40%
All Figures Indexed To
  • 01 Jan 2026

Construction Type

  • Steel Frame, Timber Frame

Materials

  • Steel, Wood

Features

  • Balcony, Flat Roof, Renovation, Sea/Loch/Lake Views, Views

A redundant rooftop solarium gave James and Katrin Gray access to a coastal plot few self-builders could find. But an unresolved brief, constant variations and the decision to build without a temporary roof turned a 16-week programme into ten months of disruption, showing how quickly a fixed-price contract loses its protection when the design keeps changing.

Become a (free) member to keep reading

To help protect my work from web scraping, I've placed it behind this membership wall. Join today to get access to all content for free.

Already an MTBO Member? Log in to MTBO

Grand Review

  • 49

Lesson Learned

  • 1
Thorough Planning Is Crucial

Invest ample time in the planning phase, including design and logistics. Rushing this stage often leads to costly and time-consuming changes later on.

  • Planning Permission, Time Management

Grand Review

  • 49

Lesson Learned

  • 2
Consider Hiring An Architect

While working with a building engineer can save costs, an architect adds creativity and expertise that can result in a more functional and aesthetically pleasing design. Don’t underestimate the value of professional design services.

  • DIY, Professional, Working With Others

Grand Review

  • 49

Lesson Learned

  • 3
Communicate With Neighbours

Keep the lines of communication open with neighbours. Informing them about the project and potential disturbances can help maintain good relations and reduce complaints.

  • Time Management, Unexpected Costs

Grand Review

  • 49

Lesson Learned

  • 4
Budget For Contingencies

Expect the unexpected and set aside additional funds for unforeseen costs that may arise during the build, such as structural issues or design changes.

  • Budget, Unexpected Costs

Grand Review

  • 49

Lesson Learned

  • 5
Be Wary Of Design Changes

Frequent changes to the design can significantly delay the project and escalate costs. Limit alterations once construction is underway to avoid complications.

  • Budget, Design

Grand Review

  • 49

Lesson Learned

  • 6
Protect The Structure During Construction

Ensure proper weatherproofing is in place, especially in locations prone to rain. Neglecting this can lead to water damage and further expenses.

  • Challenges, Construction

Grand Review

  • 49

Lesson Learned

  • 7
Realistic Timelines

Recognise the complexity of construction and set realistic deadlines. Underestimating the time required can lead to stress and rushed work.

  • Time Management

Grand Review

  • 49

Lesson Learned

  • 8
Understand Your Builds Limitations

Be aware of the constraints of building on top of existing structures, such as planning regulations and structural support requirements.

  • Regulations

Grand Review

  • 49

Lesson Learned

  • 9
Involve Stakeholders Early

If other residents are impacted by the build, involve them in the planning process early to garner support and minimise resistance.

  • Working With Others

Grand Review

  • 49

Lesson Learned

  • 10
Accept Compromise On Aesthetic Choices

While personalisation is important, be prepared to compromise on some design aspects to maintain the overall functionality and integrity of the build.

  • Design

Grand Review

  • 49

Lesson Learned

  • 11
Document Changes And Costs

Keep meticulous records of any design changes, associated costs, and communications with contractors to avoid confusion and ensure that everyone is on the same page.

  • Budget, Reflections

Grand Review

  • 49

Lesson Learned

  • 12
Revisit Contractual Agreements

Review contracts thoroughly to understand how additional changes might affect pricing—some projects allow for fixed contracts, but frequent changes can lead to increases in overall expense.

  • Budget, Working With Others

Grand Review

  • 49

Lesson Learned

  • 13
Stay Engaged During Construction

Even if you have delegated management to someone else, remain engaged in the process. Frequent site visits can help you stay aware of developments and needed decisions.

  • Challenges, Construction, Working With Others

Grand Review

  • 49

Lesson Learned

  • 14
Prioritise Sound Insurance Coverage

Ensure that the project is adequately insured to cover any potential liabilities or damages that may arise during the build.

  • Budget

Grand Review

  • 49

Lesson Learned

  • 15
Prioritise Quality Over Speed Or Cost

Often, skimping on quality materials or rushing the build results in greater long-term costs. Investing in quality from the start pays off in durability and satisfaction.

  • Budget, Design, Materials

Acknowledgment:

This is a non-commercial review carried out for the purposes of study in developing an understanding of the requirements of self-build in the UK.

The views and opinions expressed are my own and is not affiliated in any way with Grand Designs or Channel 4.  All information on this page has been gathered from publicly available sources.

The plot/site information was located using Land Registry and The Department for Levelling Up, Housing & Communities Data which contains public sector information licensed under the Open Government Licence v3.0.

The lessons learned are derived from my interpretations and observations of a publicly disseminated case study and are in no way meant to be a substitute to the original.

Click here to view the original case study on the Channel 4 website.

More
Reviews

Log in to read this content

We'll email you a magic code to log you in without a password.