Frequently Asked Questions

Most of our work is residential and commercial extensions, loft conversions, basement conversions and new builds. We draw up the plans for planning permission and building regulations, and our engineers produce the structural calculations and details. We also design special foundations and drainage, and carry out structural surveys, Flood Risk Assessments (FRA), Basement Impact Assessments and lease plans.

Yes. We measure up the property, draw the existing and proposed plans and submit the application to your Council for you. If the planning officer has questions or wants changes, we can help with them.

If you live in a house you may benefit from Permitted Development Rights. The proposed design needs to meet certain criteria set out in the Town and Country Planning (General Permitted Development) (England) Order 2015, and there must not be any existing planning constraints on your home. For peace of mind, we always advise our clients to request a Lawful Development Certificate from your Council, which is the only authority that can certify whether the proposed works meet the Permitted Development Rights. We can request it on your behalf.

This is the hard choice, because there are lots of practices and individuals who all claim to be the experts. In our view you should only employ architects who are registered with the Architects Registration Board (ARB) and the Royal Institute of British Architects (RIBA), because these are the only nationally and internationally recognised architect memberships.

A structural engineer should be chartered and a member of an institution of civil or structural engineers. They should also have experience in structural design projects, because it is quite different to other disciplines of engineering. This is one of the most important decisions to make – otherwise you could be putting yourself in danger, ending up with financial losses and possibly losing future building insurance.

All practices and individuals should have up-to-date Professional Indemnity and Public Liability insurance. It is best to select practices with both architectural and structural engineering competence, as this makes the project better run, coordinated and seamless – with one point of contact and fewer delays or miscommunication. Services should be value for money, but that doesn’t mean they need to be cheap. Professionals should be open to innovation; this is how you put your own mark on your project.

They are the detailed drawings and specification that show building control how the work meets the regulations: the structure, fire safety, insulation, ventilation and so on. You need to submit them to the building inspector before you start construction to get the final certificate, and your builder will also use them to price the job and build it.

Almost always. If you are taking out a load-bearing wall, putting in a steel beam, adding a floor in the loft, building an extension, adding a new basement or putting up a new building, the building inspector will need calculations. We can design the steels, joists and foundations and give you construction drawings that the building inspector and your builder can work from.

Strip and trench fill foundations for most extensions. Where the ground is poor or clay, or there are trees nearby, we may suggest a raft or a piled foundation instead. We also design underpinning for existing construction, reinforced concrete and retaining walls.

Yes. One of our engineers will visit, look at the cracking or movement and write a report saying what may have caused it and proposing possible solutions. Buyers, mortgage lenders and insurers often ask for this kind of report.

Yes, including the retaining walls, underpinning, waterproofing and drainage. A lot of London councils also ask for a Basement Impact Assessment with the planning application, and we can prepare that too.

If your property is in Flood Zone 2 or 3, the Council will usually ask for one with your planning application. We can prepare the FRA if it is needed, proposing mitigation measures.

Yes. We draw lease plans for flats and commercial units to Land Registry standards, for new leases, lease extensions and sales.

We are based in Colchester and work across Essex and London within the M25, Ipswich and Suffolk, Southeast London (Bromley, Lewisham, Catford, Dulwich and Croydon), and Kent including Dartford. If you are further afield, ask us anyway.

Yes. SDS is a RIBA Chartered architectural practice, we are registered with the Architects Registration Board (ARB) and the Institution of Civil Engineers (ICE), and our work is covered by PI insurance.

Every project is different, but we will let you know our cost before we start. Call us on 0120 658 4784 (Essex) or 0208 432 0807 (London), or send a message with a few details and we will send you our fee proposal.