Berkeley Road, Crouch End, London
Berkeley Road, Crouch End
Bolbec House, Knightsbridge, London
Bolbec House, Knightsbridge

What is a Structural Engineer and what do they do?

A Structural Engineer is a professional who can give advice on structural issues and provide the necessary calculations and drawings to ensure buildings are safely built (i.e. so they do not sink, collapse, warp etc). Structural Engineers prove this by mathematical calculations and drawings in order to satisfy the Local Authority Building Control that a design is safe. This work complements the work of Architects. Architects don’t prepare any structural calculations. It is widely accepted that Structural Engineering is about ensuring a structure is capable of ‘standing up’ and can withstand the pressures of use that the building is subjected to – including the potential weather conditions for the locality.

Do I need a Structural Engineer?

The answer to this question depends entirely on the nature of the work you are carrying out. If the work is purely decorative and no additional loads are being transferred onto your building, and heavy items like baths, pianos or sculptures are not being installed, then it is unlikely that you will need an Engineer. If however, load-bearing walls or chimney breasts are being modified or removed you will need an Engineer. Similarly, if new structural elements are being constructed such as new roofs, floors or foundations then it is again crucial that you employ a Structural Engineer. If you want to remove a wall and you are not sure if it is load bearing then you should also employ an Engineer to review the wall and the structure before its removal. The Engineer will be able to give you valuable advice and they will also be able to prepare the necessary calculations and drawings required for Building Control Regulations. It is advisable to always check whether you need a Structural Engineer, rather than assume you don’t need one.

Note - Most house extensions will require some sort of structural calculation as the existing external wall will be punctured to provide access to the new building.

When do I need a Structural Engineer?

If your project requires planning approval and you have employed an Architect to obtain planning permission it is unlikely that you will need to employ an Engineer until you have got planning approval. It is unlikely that you will want to pay for the services of a Structural Engineer to structurally design a building you have not yet got planning approval for. For complex projects that include the building of new basements many councils now require some structural input at planning stage. Your Architect will inform you if this is necessary.

For projects that do not need planning approval your Architect may advise you to employ a Structural Engineer whilst they are producing your Building Regulation’s plans, they can get initial input of the sizes of beams and columns and incorporate these into the aesthetics of the building.

How much will the Structural Engineer cost?

Unfortunately it is hard to say however if you can e-mail PDFs of your Architect’s proposed and existing drawings then we can provide you with a fee proposal within a couple of days. One way to limit engineering costs is to reduce site visits to a minimum. If you employ a competent builder it is less likely they will require the Engineer to visit site on a regular basis and should be able to get answers to most queries over the phone. For most smaller domestic works the Engineer should not have to visit site more than once.

Once I’ve employed a Structural Engineer what happens then?

The Architect will usually issue his drawings electronically to the Structural Engineer. It is likely that the Engineer will require some site investigation works to be carried out to confirm the profile and depth of existing foundations and/or require the existing joists to be uncovered so he can see which way they are spanning. The Structural Engineer will issue a drawing showing where they want a builder to do these investigation works. Once this work has been completed the Engineer will visit site before developing their drawings and calculations. The Engineer will then produce their own structural drawings.

Once the scheme has been developed and is ready for tender the Architect will submit the Engineer’s documents for Building Regulations approval. At the same time builders will be able to give you tender prices for the works based on both the Architects and Engineers drawings. You will then appoint a builder and the works will commence.

How long does it take to produce your calculations and drawings?

Generally for typical smaller domestic extension or refurbishment works the Structural Engineer will require two weeks from the time they visit site to produce tender drawings and calculations. This can vary depending on the scale of the project.

Do I need ‘Full Plans’ Building regulations approval or can I do the works under a ‘Building Notice’?

The difference between these two applications to your local council is that a ‘Full Plans’ application takes approximately 8 weeks to get approved but when it is approved you have the peace of mind that the Building Control Officer will not ask your builder to alter anything as long as they are building to the Architect’s and Engineer’s plans. This is normally the preferred application for larger complex projects. A ‘Building Notice’ is submitted to the council 48 hours before the works are due to commence on site. The Building Control Officer has the right to alter anything they do not think is suitable when they inspect the building site during the works. This is the most common approach to applying for Building Control approval with small domestic works.

Do I need Planning permission?

We would recommend you seek the advice of your local council and an Architect.

Do I need an Architect?

Whether you are after a modern, individual, ECO friendly home or simply want to add a two-storey extension to a modest terrace house, it is likely you will need an architect. While the credit crunch is preventing many people moving, an architect could be just the person to conjure some extra living space from your existing home.

Where will I find an architect?

Look at our web site partners section, we work regularly with all the architects featured there.

Ready to contact Symmetrys?

Please find our details on our contact page.