Structural Engineering for Renovations and Extensions

Renovating or extending your family home? Removing walls? Need more space? It’s an exciting time and Cornell Engineers is here to help you with the specialised structural engineering you’ll need to support your project.

Preparation – What do you want to achieve?

What do you want to achieve? Do you want more living space? Open up a room?

Home renovations and house alterations might include:

  • raising an existing house to create downstairs living areas
  • Remove a wall and add an island kitchen bench!
  • an internal staircase.
  • a double garage.

House extensions might include:

  • adding another bedroom
  • a new deck extension to increase your outdoor living space
  • adding more living space.

Getting a Plan Together

A building designer or architect can help guide your home renovation decision process.

The architect will define your renovation or extension goals and then present ideas for achieving them. They will also give you advice on building approvals and building regulations.

We recommend using a building designer that is a member of the Building Designers Association of Queensland (BDAQ) or an architect that is a member of the Australian Institute of Architects.

A good architect and building designer will also speak to you about the cost of the project to help you set aside the right amount of money for your project.

An Engineer’s Inspection

Cornell Engineers can inspect your property before you begin your extension.

Our inspection will help identify problems or opportunities for your proposed house renovation.

Our building inspection is normally conducted once the building plans are prepared but we’re happy to inspect your property before you get started to confirm the project is worthwhile.

Use us to identify load-bearing walls, bracing walls, and support points. Let us check and advise on removing or relocating existing columns and walls.

We will help you identify solutions to problems such as soft soils and underground obstructions such as sewer mains or electrical conduits.

This house has been raised and will be built-in downstairs.
House raise renovation project in progress in Brisbane.
Kitchen renovation adds value
New kitchens look great in existing houses.

Design and Documentation

Once your goals have been defined, the formal design process can begin.

Your building designer or architect will prepare working drawings. The set of working drawings will normally include a site plan, floor plans, building elevations (side views), and basic construction details.

Cornell Engineers then designs and draws the structure. This includes:

  • footings
  • slabs
  • steel, timber and concrete posts and columns
  • floor framing including floor joists, bearers and steel beams
  • wall framing including studs, top plates, bottom plates and lintels
  •  roof framing including rafters, roof beams and connections

We normally require a soil test and a copy of your designer’s drawings before we can start (but ask us first).

Our drawings are then prepared using a drawing program called AutoCad. Our drawings are sent to you as .pdf files that are easy to email to your builder and private certifier.

When we issue a finished set of drawings, we will prepare a “Form 15” engineer’s design certificate certifying the structural elements that we have checked.

Some building designers design and draw the structural elements as part of their design process. In this case, Cornell Engineers simply works with the building designer to make any changes to the structural drawings that we deem necessary. We’ll then prepare and issue a Form 15 structural design certificate.

Sample Form 15 which is signed by a structural engineer

Certification and Building

You’re getting closer to starting building!

Engage a builder that is licensed for your type of work. Check the Building Services Authority (QBCC) website. There is also information on the QBCC site regarding building contracts, insurance and the complaint process.

Your builder will compile and lodge the working drawings and engineering drawings with a private certifier. Plans used to be submitted directly to council for approval but now you need a private certifier to do this for you. We work with some great certifiers. Check our links page for a certifier. Certification approval should be received before building commences on site!

Once the builder starts on site, Cornell Engineers can assist with inspection and approval of footings, slabs and framing. Check with your certifier to ensure that they don’t need to inspect these elements also. We’re also available to modify our designs or provide verbal advice if something unexpected is discovered in the walls, roof or in the ground.

More Information

For more information on contracts and building work, the QBCC has heaps of information on building, renovating and buying properties. Refer to this website: QBCC Building and Renovating.

For more information on extensions, raising and renovations in Brisbane, check out this website:
Brisbane Council Renovating Guide.

Read some handy design guides that might help with your renovation.

Check out this gorgeous home renovation project for some home renovation inspiration: