How long does an extension take?

Hitting the go button on a home renovation or home extension is a very exciting moment. You are beginning a journey which will end with a more efficient home. Everyone starts the design phase with a different idea for when they intend to build. Here at Home Tales, some of our clients are rushing to get the design done and dusted, and the build started as quickly as possible. Others are fairly relaxed, and envision their build starting sometime within the 3-year window. Regardless of when you intend to build, it’s still important that you understand the different timelines associated with each stage of the process. 

Avoid the quick fix 

If you want your project completed as soon as possible, do watch out for the companies that promise you a quick turnaround. Building work is not something you want to rush. We frequently meet with prospective clients who have been promised ridiculous timelines, and unfortunately, some companies use this to entice you in. If something sounds too good to be true, it probably is. 

We thought we would run through the typical timelines of a home extension to give you a realistic idea of turnaround times.  


The architectural design phase is an important moment of your project. It lays the foundation for your entire project. Establishing an effective design is imperative to ensuring you make the most out of your project. Take lots of time to consider options and really think about the practicality of your design. A good architectural designer will help you build on your own ideas, and you want to consider each one properly. At Home Tales, we offer unlimited amendments prior to planning, so you can experiment with lots of designs. For this reason, the duration of this phase varies massively. We would say you can do it within 21 days at minimum. Ideally, you would give yourself longer, so you can consider the options given to you. The average amongst all of our clients is 56 days. 


Once you have a final design, we can create your planning pack. Ground floor extensions in London typically require full planning permission, although there are some cases you can get them through permitted development. Regardless, you still need to submit an application to the council. We produce your planning drawings which include elevations and sectional details, and this takes a week or so to prepare. We then submit your application on your behalf. Once submitted, your local council will take 8 weeks to consider the proposal and either accept or reject the proposal. If they accept the scheme, we can move onto the next phase. If they reject the scheme, we are back to square one and we need to amend your design to reflect the feedback given in the reasons for refusal. Alternatively we can appeal the decision, and try to get the original proposal overturned. 

Structural and detailed drawings 

Once planning has been approved, we begin your detailed drawings. These include the structural calculations and building control compliant drawings. Structural calculations take around 3 to 4 weeks to complete. It sounds like a long time, but it is a comprehensive document (around 30 to 90 pages). It’s literally the ‘how to’ guide on supporting the structure of your home, so it’s not one you want to rush. 

Party Wall 

Party Wall (PW) is likely required if you are extending your home in London. Depending on the scope of works involved, you may be required to serve notice to your adjoining owner(s). Once you know exactly the scope of works you wish to undertake, a PW surveyor will be able to confirm if you need to serve Notice, the types of Notice(s) you are required to serve, who to, and associated costs. Once Notice is served, your neighbours have 2 weeks to respond. If they don’t respond within this time, they get a reminder letter. If they don’t respond at all, it’s an automatic dissent. In this case it can be a lengthy process, so it’s worth speaking with a surveyor to understand the associated timelines. We have a recommended surveyor here at Home Tales we would be happy to put you in touch with. 

Find a Builder

You can start the tender process as soon as you have your structural calculations and detailed drawings. Any reputable builder will want to see these before they can offer a definitive quote for the works. We have a recommended builder here at Home Tales, and we would be delighted to put you in touch with him. We also hold House Tours, so you can see the quality of work first-hand.


A typical ground floor extension will take anywhere from between 12 to 16 weeks to get a watertight shell. This means that the external doors and windows are in and the floor is ready for final covering. Plumbing is ready for the second fix (loo and sink to be fitted), and the electrics are completed. Most kitchen suppliers will offer lead times of 4 weeks to 12 weeks, so you can book this in alongside the build if you want to. It’s important to remember that some items might lengthen your time on-site. For example, if you are opting for an all-glass roof design, this adds 2 to 3 weeks to your build. The reason for this is because you are ordering bespoke glazing. As a result, the glazing cannot be ordered until the frame is ready on-site. 

A loft conversion will take around 12 to 14 weeks, depending on the scope of works involved. 

If you would like to discuss the timelines of your own project, get in touch with us today on 020 7043 2378 or email us at You can also book a consultation directly via our live bookings page. 

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