metropol » engineering

Tag: engineering

Subsidence and its risks

Post-quake every day New Zealanders were introduced to a number of new terms relating to engineering and ground movement.



One of those terms was subsidence; the gradual downward movement or sinking of an area of land which can cause the foundation of a home to gradually settle in one area or across its entire footprint.

Subsidence can result in expensive structural repairs, which may be a deal breaker for many house hunters.

For those homeowners looking to sell their property, the structural defects resulting from ground subsidence can significantly reduce their final sale price.

Mainmark Ground Engineering Sales and Business Development Manager James O’Grady fills us in on how to protect ourselves.

“While astute homeowners and buyers will recognise some of the warning signs of potential subsidence, major structural faults or safety hazards may not be visible at first glance,” James says.

“Extensive foundation damage should be fully assessed by a suitably accredited structural or geotechnical engineer, to identify the cause, how extensive the settlement is and whether the underlying cause of settlement requires fixing,”

The common causes of foundation ground issues often relate to moisture in the soil beneath the home’s foundations, he explains.

Different types of soil (such as reactive clays, sand and silt, fill, and organic soils) behave in different ways to changing moisture levels, so consider the following when investigating the likely cause:

• Water ponding around the house
• Excessive moisture leaking into the foundation ground, often due to broken pipes, making it too wet
• Invasive tree roots searching for water, making it too dry.

In many cases, foundation issues can be resolved quickly and efficiently using modern ground engineering solutions that are less invasive and costly than traditional underpinning.

Fixing the problem for the long term requires correcting any issues that might have caused the foundation damage and this may also involve consulting a plumber or other expert.

James recommends CSIRO Publishing’s Foundation Maintenance and Footing Performance: A homeowner’s Guide as a valuable reference and says that if signs of subsidence have appeared, you need to consult structural and geotechnical engineers or ground engineering experts.

Mainmark has treated more than 11,000 sites throughout Australasia, from single-storey homes to large commercial buildings.

For more information and advice about ground engineering issues and remediation solutions, contact Mainmark on 0800 873 835.


Diverse engineering services: Babbage Consultants

Established 80 years ago, the 100 percent New Zealand-owned and operated engineering practice Babbage provides structural, geotech, civil, building and engineering design services, as well as building surveying and ecology reporting services.



“We have a solid reputation for delivery across the whole of New Zealand, with the Christchurch and recently opened Queenstown office delivering design solutions to all corners of the South Island,” South Island Business Manager Matt Harris says.
Furthermore, Babbage’s sister company Bioresearches is a specialist ecology and environmental consultancy.

With the introduction of building surveying, Babbage is also supplying assistance to the commercial real estate sector, property investors, owners and body corporates. By undertaking pre-purchase due-diligence assessments, facility management reviews and long-term maintenance plans, Babbage mitigates client property land acquisition and disposal risk, including providing advice regarding commercial lease negotiation and review.

The team’s integrated value-added design philosophy is apparent in the high-end 1,417m2 Belfast Terrace development which overlooks central Queenstown. The successful delivery of the nearly completed Hyundai showroom on Christchurch’s Durham Street also illustrates Babbage’s ‘single point of contact’ formula, prioritising the ability to talk directly to the senior staff involved on each venture.

The personal touch means not only happy retained and repeat clients, but key staff as well, which Babbage recognises ensures continuity of relationship management and strong sector knowledge. Contact Matt Harris on 027 706 7933 or




Surveying residential damage: Fraser Thomas

Fraser Thomas’ areas of engineering expertise are many and varied. One particularly close to some homeowners following the Canterbury earthquakes is the company’s work surveying damage to residential buildings.



“An unfortunate consequence of the earthquakes is that there have been a number of disagreements between homeowners and insurance companies about the causes and severity of damage to homes,” says David Mawhinney, Senior Surveyor with Fraser Thomas.

“In order to reach resolution on those disagreements, it is often necessary to have independent experts provide evidence about the elements of a building that may have sustained damage. As surveyors, we are trained to take measurements of appropriate accuracy and present the data collected in a user-friendly format for others to understand and interpret.”

Building elements often measured include:
• Land movement
• Verticality of walls, window sills, door frames and piles
• Levels of floors, ceilings and foundation bearers

“We are contracted by either of the parties in a dispute. There are always different methods of measuring building elements ranging from GNSS to lasers to tape measures amongst others. The most accurate, reliable and efficient methods must be chosen and can sometimes be quite time consuming. The outcome of the survey is of great value to the homeowner so it is important to get it right.”

For the Fraser Thomas team these surveys are extremely interesting. “They are unique – a kind of detective work – and it is professionally satisfying if we can contribute to fair and reasonable resolution of disputes.”



Engineering Excellence: Babbage Consultants

“We are absolutely committed to our clients. We believe in listening to them, giving them expert engineering advice and getting results,” says Matt Harris, Business Manager of Babbage Consultants’ Christchurch office, which serves the South Island.



“Those close working relationships have been the key to our success and strong growth in the South Island where we have projects underway in Christchurch, Nelson, Queenstown, Wanaka and elsewhere.”

Babbage Consultants’ 80 year nationwide history and reputation for excellence in engineering is another core factor in its expansion. The company is a multi-discipline practice providing structural, civil, geotechnical and environmental engineering expertise as well as planning and building surveying, to developers, industry, commercial businesses, government departments and local authorities.

“Trusted knowledge, experience, innovation and clear communication are the hallmarks of our work. We have a distinctive way of looking at and resolving issues and challenging situations so we can make a difference to our clients, to the communities we serve and to the environment. On construction projects clients can rely on us to think outside the square to provide cost effective engineering solutions.”

Totally Kiwi owned and managed, Babbage works with clients on all phases of developments and teams with its colleagues around the country to ensure clients have access to all the expertise required to complete high-quality projects on time and on budget.

To get started on your next project you can contact Babbage Consultants on 03 379 2734 or email


Cephas Rock

Structurally sound: structural engineering firm Cephas Rock

Naturally when it comes to structural engineering firms, you want a name you can trust, which is why Cephas Rock Limited should be top of your list.

Cephas Rock

Founded by experienced Chartered Professional structural engineer Joshua Wong in 2010, Cephas Rock Ltd specialises in the property service industry. Joshua and his experienced team are well trained, qualified design and structural engineers, able to provide you with a range of services to cater to all budgets.
Whether you are undertaking a new build or planning an extension on your existing property, you can be safe in the knowledge of Joshua’s experience of more than 500 build projects. Ranging from single storey houses right up to the very best architecturally designed homes, Cephas Rock will meet with you and your architect and go over the design to completion process step by step.
Along with its structural engineering services, Cephas Rock can provide geotechnical reports to determine the ground conditions of your site.
After nearly a decade of seismic activity battering our city, the structural assessments carried out by Cephas Rock are also essential to give you a clear understanding of the potential damage your building has sustained and its repair methodologies etc.
For more information on what Cephas Rock Limited has to offer, visit for more information, or phone
03-338 5387.

Customlight Engineering

An impressive line-up: Customlight Engineering delivers the goods

The line-up of designs and products Customlight Engineering puts out is nothing short of impressive.

Customlight Engineering

Design Engineer Glen Wykes bought the company three years ago, but he has been in the industry for most of his adult life. With his wife Toni-Jane, he has grown the business from its Treffers Road premises, where it manufactures for the lighting, sheet-metal, signage and building industries, among others. Its clientele covers a broad spectrum, from homeowners to international hotel chains, and from retail outlets to universities and hospitals.
Products range from steel gates for residential and commercial clients to metal staircases, window flashings, and presentation furniture such as computer stands and lecterns at the University of Canterbury, Lincoln University and ARA, with home dialysis trollies also made for DHBs.
Glen’s innovative thinking and design skills have seen LED backlit mirrors adorning motels in Melbourne, Fiji and New Zealand, and children running and playing on their custom-built playground at Cathedral Grammar School. There may be no end to Glen’s potential, with lighting units for salmon farms currently under development.
All this and much more suggests Customlight Engineering is the go-to place for all things related to metal fabrication, sheet metal and powder-coating, lighting and signage structures.
Glen is also focused on landscape products such as planter boxes and borders, bollards, gates and fencing. His latest creation is a pizza oven chimney and bench area for a residence in Christchurch. It is the kind of thing Glen hopes to do more of. Many, many satisfied customers attest to the quality and professionalism his company provides. See or contact Glen on 03-341 7175.

Fraser Thomas Geotechinical Engineers

Foundations right first time: we talk to local firm Fraser Thomas about finding the right geotechnical engineer

Geotechnical engineering is a highly specialised form of engineering that deals with foundation design for buildings. If the engineer gets it wrong, remediation can be very expensive.

Fraser Thomas Geotechinical Engineers

In California, insurance companies sick of paying out on claims covering negligence of incompetent engineers started a special licensing regime to ensure only qualified geotechnical engineers undertake geotechnical work.
In New Zealand there is currently no robust system in place to ensure only qualified chartered professional (geotechnical) engineers are providing geotechnical advice for building developments.
“When seeking geotechnical consultancy services, you should satisfy yourself that the engineer is appropriately qualified and experienced,” says Mason Reed of Fraser Thomas Limited.
“The Chartered Engineer register on the Engineering NZ website can confirm whether an engineer is Chartered and in which field (ie. structural, fire, civil). If you take advice on geotechnical matters from an engineer who is not a chartered professional (geotechnical) engineer, you do so at your own risk.”
Fraser Thomas has been providing expert geotechnical consultancy services for 50 years. “We have a sound understanding of geomechanics and provide foundation solutions which are best suited for the site conditions, which can sometimes result in significant cost savings for our clients in foundation construction costs.”
Fraser Thomas has a long history in identifying and mitigating the effects of a variety of geotechnical hazards ranging from residential and commercial to large infrastructure projects, such as landfills. “We have particular experience in slope stability assessments, including cliff lines/coastal erosion affects, foundation design on soft highly compressible soils, piled foundation design and the provision of foundation solutions for sites on liquefiable soils.”
In a shaky land, it is vital work.