Most house extensions need Building Regulations approval. Plan for it even if you already have planning permission or your extension can proceed under permitted development. Birmingham City Council directs homeowners to Acivico for its Building Consultancy service. For an ordinary house extension in England you can also check whether a registered building control approver can take on the project.
Choose a Route Before Asking Builders to Price
With a full plans application, you submit detailed construction drawings for assessment. This gives you a chance to resolve questions about the design before construction and gives builders a common set of information to price. For a project involving a large opening in the back of the house, changes to the drains or several trades, that can be particularly useful.
A building notice can suit eligible smaller works. The building control body does not issue the same advance approval of plans, and it may still ask for supporting details and calculations. A building notice is unavailable for some work. For example, check eligibility if your design involves building over or near a public sewer. Ask the building control body to confirm the appropriate route for your property.
Put the Technical Information in One Place
Start with the latest plans and sections, and record where the proposed work joins the original house. The technical pack should make it possible to review the structure, thermal details, ventilation, drainage and relevant fire provisions. Include structural calculations where the design calls for them, and cross-reference the beam or foundation details to the drawings. If a supplier will provide part of the design, agree who will check and integrate that information.
Before work starts, agree who is submitting the application, who receives questions from building control and who will give the required notices. Ask the body for the inspection stages and give the builder a copy. Relevant stages may include excavation before pouring, drainage before covering and completion, but the programme should follow the instructions for your job.
Example: A Kitchen Extension to a Birmingham Terrace
Suppose the proposal opens the original rear wall into a new kitchen, and the existing drain appears to run through the footprint. Investigate the drain route and ownership before agreeing where the foundations go. Have the opening and its supports designed together, and ask the building control body when it needs to see them. If the builder proposes moving the opening during the work, ask the designer to update the details and notify building control as appropriate before that work proceeds.
Keep the Records for Completion
Keep inspection correspondence, revised drawings and relevant installation certificates together. Arrange the final inspection and send the requested documents or declarations. Obtain the completion certificate from local authority building control, or confirm the final certificate process if you used a registered building control approver. Those records can help answer questions when you sell the home.
If the planning drawings are ready, ask Ashbridge Design about a Building Regulations drawing pack for your extension.