Architectural drawings show what your extension or loft conversion will look like; structural design proves that it will stand up. We prepare complete structural packages for rear and side extensions, loft conversions, dormers and mansards, covering steel and timber beam design, new and altered floor structures, foundations and load-bearing alterations. Our calculations and drawings satisfy building control, guide your builder on site, and integrate with your architect’s proposals so the project moves smoothly from planning approval through to construction.
Almost every extension or loft conversion involves structural work that building control must approve before or during construction. You will typically need calculations when:
If your architect’s drawings are marked ‘structural engineer to design’, that is precisely the package we provide.
We start by reviewing your architect’s drawings and visiting the property to understand the existing structure, since older London houses rarely match textbook assumptions. We then develop the structural scheme, calculate the loads and size each element, from ridge beams and trimmers to padstones and foundations. You receive a coordinated set of calculations and structural drawings, prepared for submission to building control. During construction we remain available to answer builders’ queries and to resolve any surprises revealed once the structure is opened up.
A typical package contains full calculations for every structural element, general arrangement drawings showing beam layouts, sizes and connection details, foundation designs where new walls are proposed, and specification notes covering materials, bearings and temporary works. Everything is presented in the format building control bodies expect, whether you use the local authority or an approved inspector. Clear drawings also help builders price the work accurately, reducing the risk of provisional sums and mid-project surprises appearing in your quotations.
Design fees reflect engineering effort rather than floor area alone. The main variables are the number of structural elements to design, the complexity of the load paths, whether the roof is being substantially rebuilt, ground conditions and foundation requirements, the age and condition of the existing building, and how much coordination is needed with your architect and other consultants. A straightforward rear extension needs far less design time than a mansard loft over a maisonette, and we quote a fixed fee once we have seen the drawings.
Building control approval depends on calculations that are correct, complete and clearly presented. Our RICS-qualified chartered surveyors and structural designers work to current codes and standards, carry professional indemnity insurance, and have long experience of how London’s building control bodies review submissions, which helps you avoid rejection letters and delay. Just as importantly, professionally prepared structural documents protect you later: lenders, buyers and their surveyors increasingly ask for evidence that alterations to a property were properly engineered and approved at the time.
Structural design does not happen in isolation. We coordinate closely with your architect so that beams, steels and downstand positions respect the design intent, ceiling heights and service routes, and we flag structural implications early, before they force costly redesign. Once work begins we speak your builder’s language, responding quickly when the opened-up structure differs from what was assumed. Many of our instructions come from architects and contractors we have worked with repeatedly across west London, which says much about how the collaboration works in practice.
Planning an extension or loft conversion? Send us your architect’s drawings and we will provide a clear fixed-fee quotation for the structural design package. Contact Notting Hill Surveyors to get started.