Your House Extension Checklist: What Needs To Be Done Before Construction Can Start?

Updated: Apr 28

For most house extensions, the planning and administrative tasks that come before the building stage, take a lot longer than the building itself. For those about to embark on this journey, it is very important to know what needs to be done and in what order it needs doing. Below we have outlined the vital milestones leading up to when construction can begin.


Your Own Design


Before approaching an architect or a construction company, it is important to have a clear idea in your own mind of what your project is. Specifically you need to know:

-What your house extension is going to look like

-How you are going to use your new space

-How much money you are willing to spend


A clear and detailed brief at this stage is vital as the architect will rely heavily on this instruction to draw up your scaled design.



Finding an architect


Once you are happy with your own design, it is time to approach an architect. Architects either work independently, as part of a firm or in-house at a construction company. To find a good architect you should ask around for a trusted recommendation, conduct online research and use established databases (like the Architects Registration Board). Once you meet an architect to discuss your project, you should always review their portfolio, check how

their fees work and clarify what level of detailing they are going to put into the design -as this does change from person to person.



Your Architects Design


Once you have found an architect that you are happy with, it is up to him to put your project plan into a scaled blueprint. The architect's design must meet your living needs and fulfill building regulation codes. This drawing up stage can take between 2-6 weeks, with the variation in time depending mainly on whether you have the original drawings of your

property. If not, you’ll need to commission a measured survey to get the correct dimensions of your house on paper.



Planning Permissions


It will be up to your architect to advise on whether your particular project needs planning permission. If so, his design will have to be sent to your local authority for approval. This is a process best organised by the architects, as it is likely that they will have dealt with a lot of planning permissions before. The standard time for them to come back to you is 8 weeks, however it can take longer if they want to make alterations to the blueprint.



Building Regulations


Providing that the planning permission was granted by your local authority, the next step is securing Building Regulation approval. This differs from planning permission in that it checks that your design would be safe to live in. It ensures that your home will have structural strength, stability, sufficient insulation and fire safety compliance. There are three different types of applications that you can make, and your architect can advise you on which is best suited to your project.


- Full plans application - this is the most comprehensive option and is only usually necessary for large projects. Detailed plans need to be submitted to the building control department at your local authority and one can expect to wait between 5 weeks and 6 months before hearing back. If your plans are in compliance with the necessary regulations, you can start building. An inspector from the local authority will then make visits to your property at various intervals to make sure that the work is to standard as it progresses. Once your project is complete you will receive a certificate as a record of your full compliance.


- Building notice - This is a lot quicker than the full plans application and is suited to small or simple projects. With this type of application, there is no obligation to send plans to your local council first, you simply have to notify your local building authority that construction is about to start. You can then start building just 2 days after this notice is submitted. An inspector will then come to visit your property at various intervals to make sure that regulations are being observed as work progresses. For this type of application, you must check that your architect is sure his design adheres to the set regulations, because if not, the inspector may instruct you to demolish and re-do any work out of compliance.


- Regularisation - This type of process allows people to submit an application retrospectively, once building works are complete. Again, this type of application is risky, because a whole project may be complete when an inspector requires alterations be made, resulting in a lot of money lost.



Party Wall Agreements


Party wall agreements are only necessary if your house extension is going to affect a shared wall between you and your neighbor or if you are planning to excavate within 3 metres of a wall shared with your neighbor. If a party wall agreement is needed, then you need to notify your neighbor of your plans at least 2 months before construction starts. They then have 2 weeks to give written consent or dissent. If your neighbor doesn’t agree to your plans, or doesn’t reply at all, then there are a few more administrative processes you’ll have to follow. For more information on these, please click here to find our comprehensive guide to party wall agreements.



Finding your builders


This is also known as the "tendering process". Like architects, the best way to find contractors is through recommendations and online research. You should always approach several contractors and receive quotes from each as there is lots of room for variation between companies. Once you have found the right contractor and building team, construction is ready to get underway!



Property Makeover Ltd At Property Makeover Ltd, we offer a simplified process. Our architect, contractor and workmen are all “in-house” -meaning they have experience working together and a close professional relationship. From the design and planning stage, right through to construction, our team prides itself on close liaison and a seamless delivery. If you would like to learn more about our services and the way we work then please don’t hesitate to get in touch.