How Long Do Home Extensions Take?

One of the common questions that a builder is asked when it comes to extensions is how long will it take?  The answer to that does depend on lots of things including the style, the materials and the weather. But there are some general ideas about how long extensions should take.

The design process

The first step in creating an extension is the design process.  This might be done with an architect or may be a simple process if you are doing something like a timber frame extension from a kit.  If you are working with an architect, they will need to measure the house to create a plan and this might involve some back and forth while the plan is created.  This means it can take anywhere from two weeks to up to 2 months to get the plan in place.

Planning permission

Armed with your plan, you can check about planning permission.  You may not need this and if you don’t then the step is skipped.  But if you do need to submit the plan to get planning permission, this can add 6-8 weeks to the process while you wait for approval.  If you are declined, you will need to amend the plan and resubmit or appeal.

Building approval

Armed with planning permission or confirmation it isn’t needed, the next step is the technical design and building approval.  This is where a structural engineer looks at the foundations, beams, roof structure and other key elements. This can take around a month, depending on how complex the project is.

Party wall notices

Most of us have neighbours and you need to give party wall notices to let them know what you are doing if there are any shared walls or boundaries affected.  It can be a good idea to chat with them about this first to speed it up.

The building process

Finally, you reach the actual building process.  This depends on the type of construction and the materials used.  Timber frame extensions are usually quicker while a single storey extension can take 4-6 months and another month for a double storey extension.

This means that from the first planning through to completion, it can take as much as 12 months to get an extension added to your home.  There are ways to speed this up and there are factors that slow it down that are unavoidable. But if you expect this kind of time frame, you will be well placed to cope with the disruption.