Most people spend more time choosing a kitchen than they do choosing the builder who will construct the room it sits in. That is understandable — kitchens are visible and immediate. The builder's decisions happen underground and inside walls where they are invisible until something goes wrong. This guide is about making the right choice before that point.
Crownhill Building Services has been delivering home extensions across Milton Keynes since 2006. We know what separates a good build from a poor one because we have spent nearly twenty years fixing the consequences of decisions made before we arrived. Here is what we look for — and what you should too.
Local Experience Is Not the Same as Experience
A builder with thirty years of experience in commercial construction is not necessarily the right choice for a domestic rear extension in Bletchley or Newport Pagnell. The skills overlap but the details diverge considerably. Local ground conditions — the Oxford Clay that runs beneath much of MK — behave in ways that catch out builders who have not worked here before. Local planning requirements have nuances that a builder unfamiliar with Milton Keynes City Council may not anticipate.
Ask specifically about work completed in your area. Ask to see it. A builder who cannot point to completed projects within a few miles of your property is a builder who is learning on your budget.
Check Accreditations — Then Check They Are Current
Gas Safe NICEIC NAPIT FENSA Checkatrade — these accreditations exist because the work they cover requires qualified people. A builder who tells you accreditations are unnecessary for an extension project is either uninformed or cutting costs in a way that creates liability for you as the homeowner.
Check that the accreditations are current. Most are renewed annually. A certificate from three years ago is not evidence of current compliance. Ask for the registration number and verify it directly with the relevant body — all of them maintain public registers.
Fixed Price or Cost-Plus — Understand the Difference
A fixed price quote means the number on the paper is the number on the final invoice. It does not move because materials got more expensive or the job took longer than anticipated. The risk sits with the builder not with you.
A cost-plus arrangement — sometimes described as a day rate or a materials-plus-labour quote — means the final cost is unknown at the start. It is not inherently dishonest but it transfers the financial risk entirely to the homeowner. For a project of the scale of a home extension that risk is significant.
Every Crownhill Building Services project is priced on a fixed basis. The quote is confirmed in writing before work starts. It does not change.
Ask About Building Control — Not Just Planning
Planning permission gets most of the attention but Building Control is the process that actually protects you. It is the statutory inspection regime that runs throughout the build and confirms at every stage that the work meets building regulations. The completion certificate it produces is the document that matters when you sell or remortgage the property.
Ask any builder you speak to how they manage Building Control. Who submits the initial notice? Who books the inspections? Who responds to queries from the inspector? If the answer is vague or suggests you will need to manage this yourself — look elsewhere. Building Control for home extensions in Milton Keynes is something we manage entirely on behalf of every client from initial notice through to final sign-off.
References and Video Testimonials
Written references are easy to fabricate. A video testimonial from a named client at a specific address is considerably harder to fake — and it tells you something about the relationship between the builder and the client that a written quote cannot.
We have multiple video testimonials from completed projects across Milton Keynes available on our website. We also offer site visits to completed and ongoing projects for every potential client. If a builder cannot or will not show you their work in person that tells you something.
The Site Visit Tells You More Than the Quote
A builder who arrives at your property having clearly not looked at it beforehand — no knowledge of the area the street or the property type — is a builder who will price on assumptions rather than specifics. Assumptions in a building quote become disputes during the build.
The initial site visit should answer the ground condition question the planning question the party wall question and the access question before any price is put on paper. If it does not cover all of those points the quote that follows is incomplete.
Get in touch today to arrange your free no-obligation site visit. Browse completed extensions across Milton Keynes to see the standard of finish we deliver — or read our guide on home extension costs in Milton Keynes if budget is still the primary question.