Simple Guide to Building an Extension


Finding a Good Builder


Now that you have your final design and all the approvals you need, it is time to choose the building firm you wish to construct your extension.

We believe a good builder is someone who:

  • Is an experienced and has undertaken extensions similar to your own in the past

  • Comes with recommendations and references

  • Is reliable

  • Can start your extension within your timeframe

  • Will build your extension within your budget

  • You can have a good working relationship with


Once you have found some building firms which fulfil most or all of these criteria, we recommend that you send your preferred three the drawings and associated documents that were submitted to, and approved by, Building Control, asking them to provide a quotation for building your extension.

When you have received the quotes, you can use these costs and the above criteria to help choose which building firm you wish to build your extension. This may not be the cheapest building firm, as some of the other criteria may be more important to you.

Next, we recommend that you write to your chosen builder and formally appoint them. We also recommend that you use a standard domestic building contract to protect both you, your investment, and the building firm. There are different types of contract and your architect can advise you as to which would be suitable.

You should NEVER pay any money to your builder upfront. A standard contract will detail the payment process for you.

The Building Regulation drawings and associated documents that 3HW produce will contain enough information for a builder to both price and construct your extension - this is included in the combined package fee. For an additional fee, 3HW can undertake the builder selection process for you, including the drawing up of a standard building contract.