Building an extension can be a big project. Every project is as individual as the homeowners who embark on it and there no one size fits all guide to ensure that you achieve the results you are after. Each extension project will serve specific needs and have its own benchmarks. However, there are some core elements you must get right in every one of them. Here are a few suggestions to manage plans, budgets and contractors that will help you make your project a success.
When thinking of building an extension, be it a kitchen extension or a double story side extension, it is a wise move to be aware of construction issues that could potentially affect your project such as new construction regulations in your area, material and trade availability or price hikes.
You should be aware if any of these issues could potentially affect your time-lines and if so, make the necessary allowances. Depending on the size of your project, you should consider a time-frame of between 6 to 8 months for a medium extension though this can vary greatly depending on the project specifications, complexity and the area in which the property is located. Keep in mind that the best qualified contractors are usually booked many months in advance so allocate some buffer time to your schedule for the initiation of your project.
Managing an extension project on your own, especially if you are a novice, can be a huge task that could take a lot of your time and patience. Between requesting and assessing quotes from different trades and suppliers to sourcing the right materials, an extension project can potentially become a full-time job without realising it. You can mitigate this by seeking the advice of a quantity surveyor (QS) to help you manage the project. A QS can be also known in the industry as a Construction Cost Consultant or Commercial Manager, and their role is to keep a close eye on project finances and contractual relationships.
Be realistic about your budget. It is easy to get carried away with design ideas we see in magazines and on Instagram, but it is crucial that one is realistic about cost. Calculating a budget of roughly £ 2,000/m2 should give you a good idea of the budget needed for a good quality project. However a word of caution, the higher the specs the higher the budget needed. A good way to effectively calculate a budget is to make design decisions as early as possible. Opting for marble rather than tiles for your kitchen floor for example could have a great impact on the overall budget not only because of the cost of materials but because you might need specialised tradesmen to do the installation.

Most projects will cost more than expected. Changes in materials and unexpected hurdles can see a project’s cost increase regardless of how well things have been budgeted for. Once you have decided on a budget, it is advisable to calculate at least a 20% contingency fund. Most reputable contractors and tradesmen will help you keep to your budget. Unfortunately in every project there can be unforeseen complications such as hidden structural problems or severe weather which can increase the overall cost.
In terms of managing your project, there are multiple options depending you’re your specific needs, preferences, budget and project. You can consider hiring an architect and/or designer to help you draw up all necessary plans for your scheme and can guide you through the whole process. This could also encompass the co-ordination of the various consultants required before the project begins, including designers, structural engineers, party wall surveyors, the Building Control Officer plus any other specialists. Your architect might also be able to see you through the planning permission process. Once the project begins, the management role can be passed onto your main contractor.
If you’d prefer there are also design and build companies with in-house professionals who can take you through from the start of the design process right up until completion. For much larger and complex projects you could also consider a professional project manager to oversee everything. This could save you stress, time and crucially cost as they would have done projects similar to yours many times before.
If your budget is limited, you can save some money by project managing yourself. This can provide you with great control over budget and construction, however beware, as this also means you will be undertaking responsibility for some decisions and should these need to be rectified the onus could be fully on you. None the less, this can be a hugely satisfying experience.

You could also consider splitting the project management. For example your main contractor can project manage until you project is watertight at which stage you can take over and manage all sub-contractors such as plumbers, electricians, tilers, etc.
Have a chat with some contractors early on. An informal chat with a contractor will give you an idea of the feasibility of your project and give you a more accurate idea of time-frame and cost.
At Dominant Construction we are always keen to talk about construction. We are bespoke building experts and would love to hear about your project and explore how we can help bring your vision to life. Give us a call on 020 71186155 or book an appointment to come see us at our office in Hammersmith.