Estimating the cost of an extension is not always as simple as it sounds.

The costs of an extension, or any building projects for that matter, depends on a variety of factors. The size, specification and even your geographical location all have an impact on the costs to build.

The cost of a single storey extension, for example, can vary from £1,500 per square metre for a simple build and fit out, right up £3,000 per square metre for a high specification build. Single storey rear extensions or side return extensions will often include not only creation of the new space, but also the cost of installing a brand new kitchen, a utility area, bifold doors and a new patio area. They will also include any remedial works to the existing house affected by the new extension such as decorating and replacing floorings.

With building costs being so varied, we always recommend that you get an accurate estimate of their architectural designs building costs, to check their affordability before you talk to builders. That way you can arrange your personal finances more in advance, and will also have a benchmark to compare with the tender returns.

We have just be appointed to help a client who is hoping to extend his home near Guildford. Having achieved planning permission, our client approached a selection of local builders himself and asked them to quote for the building works. The result was a selection of quotations with widely different prices.

We are now going to go through the designs and the quotations to determine whether the tender returns are accurate and comprehensive, and to check the reason for, and the nature of the anomalies. We’ll then advise on the next steps before helping our client choose and appoint a suitable contractor.

Do you need help estimating the cost of an extension? If so CLPM’s cost team can help. We’ll take your designs and specifications and make sure we allow for all the additional individual elements involved with your project to work out an accurate estimate for you.

Call 01923 896550, email info@cl-pm.com or complete a contact form.

CLPM Project Managers cover London, Bedfordshire, Berkshire, Buckinghamshire, Gloucestershire, Hampshire, Hertfordshire, Oxfordshire, Surrey, and West Sussex. Energy Consultancy and Cost Advice services available across the UK.