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Pro Panel: What Do Structural Engineers Do and Should I Hire One?
Not sure how this specialist profession fits into your renovation project or what structural engineers do? Read on...
As a homeowner, you may be clear that you want an architect, an interior designer, a builder – or perhaps a carpenter or plumber – to help turn your dream project into a reality. But what about a structural engineer?
To many homeowners, this profession may be a bit of a mystery. Who is responsible for hiring this specialist – you or your architect? How much will it add to the cost, and do you need to consult one if you’re just knocking down a non-load-bearing wall? All these questions and more are answered by our panel of UK experts: Mark Goddard of Entuitive UK, Cat Hoad of Absolute Project Management, and Ovi Constantinescu of Model Projects.
To many homeowners, this profession may be a bit of a mystery. Who is responsible for hiring this specialist – you or your architect? How much will it add to the cost, and do you need to consult one if you’re just knocking down a non-load-bearing wall? All these questions and more are answered by our panel of UK experts: Mark Goddard of Entuitive UK, Cat Hoad of Absolute Project Management, and Ovi Constantinescu of Model Projects.
How soon should a structural engineer be getting involved in your project?
“Right after the clients agree [on] the final design,” says technical designer Ovi Constantinescu. “The drawings and calculations are required at the final stage before they’re submitted.”
The engineer should make a site visit and conduct an analysis before starting work on the drawings and structural calculations. “He or she must check the soil conditions, existing foundations and, if possible, structural walls, and draw up sketches showing this,” says Constantinescu. “Based on the structural analysis, we – the architects – will keep as many of the existing elements of the house as possible. We try to avoid demolishing unnecessarily.”
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“Right after the clients agree [on] the final design,” says technical designer Ovi Constantinescu. “The drawings and calculations are required at the final stage before they’re submitted.”
The engineer should make a site visit and conduct an analysis before starting work on the drawings and structural calculations. “He or she must check the soil conditions, existing foundations and, if possible, structural walls, and draw up sketches showing this,” says Constantinescu. “Based on the structural analysis, we – the architects – will keep as many of the existing elements of the house as possible. We try to avoid demolishing unnecessarily.”
Need an architect to guide you through the design and renovation process? Find one near you on Houzz
When should homeowners contact a structural engineer?
“People who are looking to extend a property or want a structural survey,” says Goddard, “approach us directly for our services.”
Typically, though, it will be an architect or other design professional who will contact Goddard’s firm. “Generally, we’re asked by an architect to develop a fee proposal on behalf of a client, but our contract will be with the client,” he says.
“The client can employ the engineer,” says Constantinescu. “However, communication is more efficient if the architect deals directly with the structural engineer, especially to resolve any issues and finalise the drawings.”
“People who are looking to extend a property or want a structural survey,” says Goddard, “approach us directly for our services.”
Typically, though, it will be an architect or other design professional who will contact Goddard’s firm. “Generally, we’re asked by an architect to develop a fee proposal on behalf of a client, but our contract will be with the client,” he says.
“The client can employ the engineer,” says Constantinescu. “However, communication is more efficient if the architect deals directly with the structural engineer, especially to resolve any issues and finalise the drawings.”
Which homes or designs usually need a structural engineer?
“[You need a structural engineer] any time the layout is being changed in such a way that the load-bearing arrangement of the building might change,” says project manager Cat Hoad.
“This is obvious if you are, for example, removing the back wall of a house to build an extension,” she says, “but you should also bear this in mind if you’re ‘opening up’ any walls to connect spaces or put in a new door or window.”
Let Houzz help you find a structural engineer
“[You need a structural engineer] any time the layout is being changed in such a way that the load-bearing arrangement of the building might change,” says project manager Cat Hoad.
“This is obvious if you are, for example, removing the back wall of a house to build an extension,” she says, “but you should also bear this in mind if you’re ‘opening up’ any walls to connect spaces or put in a new door or window.”
Let Houzz help you find a structural engineer
“Even if the wall doesn’t look as if it’s load-bearing, it’s definitely worth checking, especially in older houses that have been renovated in the past, as the structural arrangement might have changed from its original layout,” says Hoad. “In one house, we were removing a built-in wardrobe from a loft conversion and discovered – in time, fortunately – that one of the ‘walls’ of the wardrobe was supporting one of the roof timbers!”
Constantinescu adds that engineers will also often be called upon to investigate the soundness of a structure before it’s exposed.
Constantinescu adds that engineers will also often be called upon to investigate the soundness of a structure before it’s exposed.
Which other occasions would call for a structural engineer?
“An engineer could be used to examine defects to the structure caused by trees, drainage, cracks, or geotechnical-related problems,” says Constantinescu. “Site visits from an engineer are also important where demolition is to take place.”
“An engineer could be used to examine defects to the structure caused by trees, drainage, cracks, or geotechnical-related problems,” says Constantinescu. “Site visits from an engineer are also important where demolition is to take place.”
How much do structural engineers cost?
You could expect to pay from AU$400 to AU$600 for a building inspection report, up to AU$3,000 to AU$5,000 for an engineer’s report and drawings, or even AU$15,000 for more detailed structural plans.
As Hoad says, it all depends on the work that’s needed: “It’d be less for a simple opening up of a structural wall.
“This all then varies depending on the existing structure of the house and the extent to which you want any structural elements hidden. For example, if you’re happy to have a boxed-in ‘downstand’ beam, that’s usually cheaper than having the beam recessed into the ceiling void to achieve a flat, seamless ceiling between the two areas.”
“It’s very different from engineer to engineer,” says Constantinescu. “Some charge extra for small updates and site visits.”
You could expect to pay from AU$400 to AU$600 for a building inspection report, up to AU$3,000 to AU$5,000 for an engineer’s report and drawings, or even AU$15,000 for more detailed structural plans.
As Hoad says, it all depends on the work that’s needed: “It’d be less for a simple opening up of a structural wall.
“This all then varies depending on the existing structure of the house and the extent to which you want any structural elements hidden. For example, if you’re happy to have a boxed-in ‘downstand’ beam, that’s usually cheaper than having the beam recessed into the ceiling void to achieve a flat, seamless ceiling between the two areas.”
“It’s very different from engineer to engineer,” says Constantinescu. “Some charge extra for small updates and site visits.”
Do remember that the structural design will then need to be implemented by your builder, and that this can involve reasonably expensive materials – steel, concrete, and so on – and often quite a lot of labour time. “For example,” says Hoad, “you’d need lots of person-labour to lift and position beams in tight spaces, to dig and pour foundations, to do underpins in sequence or to negotiate around drains.”
Another cost (and time) element to factor into the structural part of your project is that you may also need a temporary support specialist as well as a structural engineer.
“They design – as the name suggests – the way in which the building is held up temporarily between you knocking down the wall holding up the floor above and sticking in the beam,” says Hoad. “It doesn’t stay up by itself… Structural engineers may not deal with that, especially for a minor job. It’s not usually a huge cost, but it’s one that’s often overlooked until later than is ideal.”
Finally, she adds, the extent of the structural work will affect whether you need to take into consideration party walls; for example, shared walls between terrace homes.
Another cost (and time) element to factor into the structural part of your project is that you may also need a temporary support specialist as well as a structural engineer.
“They design – as the name suggests – the way in which the building is held up temporarily between you knocking down the wall holding up the floor above and sticking in the beam,” says Hoad. “It doesn’t stay up by itself… Structural engineers may not deal with that, especially for a minor job. It’s not usually a huge cost, but it’s one that’s often overlooked until later than is ideal.”
Finally, she adds, the extent of the structural work will affect whether you need to take into consideration party walls; for example, shared walls between terrace homes.
The house down the road didn’t need all the support our engineer has specified – do we really need it?
“Occasionally, clients will talk to a ‘helpful’ neighbour who says, ‘When we did our extension, we didn’t need [a beam of that size/a new foundation/to underpin next door] – or whatever it is that the structural engineer has recommended,” says Hoad.
“While it’s possible that some engineers over-specify,” she says, “it’s much more likely that the arrangement of this particular house is different from your helpful neighbour’s place, or that you are doing a slightly different bit of work, or that the building regulations have changed since the neighbour did their work.”
“Occasionally, clients will talk to a ‘helpful’ neighbour who says, ‘When we did our extension, we didn’t need [a beam of that size/a new foundation/to underpin next door] – or whatever it is that the structural engineer has recommended,” says Hoad.
“While it’s possible that some engineers over-specify,” she says, “it’s much more likely that the arrangement of this particular house is different from your helpful neighbour’s place, or that you are doing a slightly different bit of work, or that the building regulations have changed since the neighbour did their work.”
What should a homeowner look for in a structural engineering company?
“The company should have a number of chartered structural engineers within the practice and have … professional indemnity insurance,” says Goddard. “Good experience of working with older buildings and the challenges of extending and modifying existing buildings is critical.”
“The company should have a number of chartered structural engineers within the practice and have … professional indemnity insurance,” says Goddard. “Good experience of working with older buildings and the challenges of extending and modifying existing buildings is critical.”
Your turn
Have you used a structural engineer for previous projects? Tell us your experience and tips in the Comments below, like this story, save the images, and join the renovation conversation.
More
Thinking of renovating? Read the difference between hiring an interior designer and an interior decorator.
Have you used a structural engineer for previous projects? Tell us your experience and tips in the Comments below, like this story, save the images, and join the renovation conversation.
More
Thinking of renovating? Read the difference between hiring an interior designer and an interior decorator.
Structural engineer Mark Goddard puts it in its simplest terms: “They’re the person responsible for making sure the building stands up. They design the load-bearing elements of the property, such as walls, columns, floors and foundations, to ensure all the building loads – people, furniture, floors, roof, wind and so on – are safely transmitted to the building foundations.
“They’ll also provide drawings, calculations and specifications on all projects where structural works are taking place,” he says.