Obtaining planning permission for your home extension project is only half of the battle. To make your project a reality the next step is the technical design process that will turn your ideas into a well-managed and buildable project.
The key questions at this stage are how can we build this project well? For us, the technical design process is typically broken down into three stages before works start on site.
Stage 1 relates to obtaining building regulations approval. The building regulations are a series of compliance requirements that cover all building work in the UK to ensure they are constructed safely and effectively. The regulations are described by a set of key Approved Documents, covering elements from Structure (Part A) to Fire (Part B), Energy Efficiency (Part L) and Accessibility (Part M) among others. The process for obtaining ‘Building Regulations Approval’ sits entirely separately from the planning process and can be dealt with in a few ways.
For the smallest and simplest of projects obtaining a Building Notice is a possible route to obtaining approval. This involves informing a Building Control officer that works are to start at least 24 hours before the planned start on site. No drawings are submitted and works are checked by building control as the project progresses. There are significant risks in this approach in that the technical design has not been resolved before works start. Any issues raised by building control will need to be rectified, often at a significant cost.
In almost all cases we strongly recommend an alternative route, the preparation and submission of a Full Plans Building Regulations Application. This involves the preparation of detailed technical drawings for submission to either a Private Approved Inspector or Local Authority Building Control Office for the plans to be checked before any works start on site. This allows for any potential issues to be resolved on paper, before any spades touch the ground on site.
During this stage of the technical design process, we will bring on third party consultants to form part of the wider design team including – in almost all cases this will include a structural engineer, a ground investigation engineer, and a SAP/ Energy Assessor. In some cases, this may also include a Fire Engineer, Health and Safety Consultant and an Acoustician. Each of these consultants will contribute to the technical design and demonstrating compliance against the relevant part of the building regulations.
For us, this stage is all about finding the most practical and effective technical solutions for realising your vision. We will think about the best structural method for the walls, floor and roof of the building – as well as the best methods for insulating the building and achieving the optimum energy performance of the home. We will help you to think about how you will keep the home cool in the summer, and warm in the winter and how to maximise ventilation and avoid the potential for condensation or mould in the property. All the while we will be balancing your budget constraints, achieving compliance and creating a beautiful space that you can be proud to call home.
The next stage of the technical design process relates to the production of construction details. This is a set of large scale construction detail drawings that we liken to a set of IKEA instructions. These drawings aren’t always required to demonstrate compliance with the building regulations, but can be invaluable for your builder in ensuring that they construct the project in line with your vision. We are always targeted and pragmatic with the construction details that we produce. For example, if your intention is to appoint an experienced builder that has constructed hundreds of brick built extensions to build you a simple brick built extension – it is highly unlikely that they will need a raft of details to effectively build your project. However, if we are pushing the boundaries with the design of your extension – using materials and details that are uncommon in ways that might not have been tried before – creating a set of high quality and well-resolved construction details will be key to make sure you don’t end of with problems on site.
Finally, the next stage of the pre-construction process relates to finding you a builder to construct you extensions. In some cases, clients come to us with a preferred builder in mind for their project – it could be a friend, acquaintance or someone that you have worked with on a previous project. In other cases, you may have never carried out a project like this and have no idea where to start with finding a builder. We can provide as much or as little support as required, regardless of your circumstances, to make sure that the best builder possible is found for your project. We call this the Tender process. Essentially, we are aiming to bring as many suitable builders to the table to provide you with a price and timescales for your project so we can then help you to pick the person that is right for you.
Cost and timescales are key to the success of any project – however quality is just as important to make sure you are happy with the result that you create. We always aim to push beyond finding the cheapest builder possible, but taking the time to meet with and understand all the builders providing a price to make sure they are capable of delivering your vision. This could involve speaking to their past clients and visiting their past projects to assure yourself that they are the people for the job.
Once the technical design stage is complete – you and your builder will be very nearly ready to start works on site. The critical last piece of the puzzle is how you appoint your builder. We always recommend entering into a formal contract with whoever you appoint. At the very least this contract should include the total agree cost of the work, the end date for the project and arrangements for resolving any disputes. We are very aware that some builders like to work on ‘handshake’ agreements and prefer to not be tied into complex contracts – however we always advocate for the maximum level of protection for you as a consumer.
We generally suggest using the Royal Institute of British Architects (RIBA) construction contracts. These are robust documents, backed by the RIBA’s legal team, but written in a simple and accessible way that works in the interest of clients, builders and designers alike. As part of the tender process we will always discuss with yourself and the builder the optimum contract to be put in place and work through any questions and queries about however things will work once the project gets going.
In most cases, the key functions of the contract will be a monthly site visit including ourselves and the builder to evaluate the amount of work carried out, address any queries and ensure that the payments you are making stack up with the amount and quality of work carried out to date. It is always our hope that things run smoothly on site and disputes are avoided – but having a contract in place helps to give us all guidance on where to go and what to do if things don’t go as planned.
Another critical component of any good building contract is the practical completion process, handover and snagging. The RIBA suite of contracts ensures that before any final extension works are signed off that all parties are satisfied that things are complete. The contracts also advocate for a detailed handover process including operation and maintenance manuals to make sure you know how to keep your extension in the best shape moving forward and how to work any and all of the new bells and whistles that might have been installed (think automatic blinds, underfloor heating and new air source heat pumps).
Finally, any good contract should include a minimum 1- year snagging period enforced by a good retention fee (essentially the carrot or stick to keep your builder engaged with the project). The snagging period is essentially a window of time to let the dust settle on your new extension, let you inhabit the space and stress test all its features. If any cracks literally or metaphorically show in this period the builder is obligated to come back and fix these for you, at their cost – giving you the piece of mind that your project will be everything you hope for.
Our job as architects at this stage of the design process is to leave no stone unturned or question unanswered before works start on your project. Extra time and cost during the technical design process to work out specific details can save you significantly more time and cost if things are left to be resolved on site.
The technical design process will take you deeper into the nuts and bolts of your project and help you to understand not just how it will be built but how it will continue to work for you once it is complete. Concept designs we might have developed to the next level of detail including detailed floor plans and elevations and often more detailed external 3D visuals. As well as using these drawings to help you understand how your project will work for you and look in reality – we also use these as tools to convince the planners and your neighbours that the proposals are acceptable in planning terms.
The technical stage is filled with complexity – it is at this stage that responsibility as architects is at its deepest with a requirement to collaborate with external consultants and specialists to ensure a high quality and compliant result for your home extension project. Working together with our network of contacts, we will help to bring your project to life in the best, and least stressful way possible.
If you’re thinking about a home extension project – get in touch with our team at enquiries@planningdesign.co.uk or call 01332 347 371.
Home Extensions – A Gallery
