Addington House

Addington House
Cannon Hill Crescent, Christchurch, NZ
Sam McCarthy
Completed August 2017
Design and Structural Engineering
Engco Engineers and Simon McCarthy


Having utilised XLam Cross Laminated Timber previously, the owners were motivated to repeat the process, this time with a new house located in an earthquakes-affected area on the Mount Pleasant hillside. A badly damaged house had previously been demolished to provide the site.

Utilising their own professional qualifications and experience, the Addingtons designed and project-managed the house themselves, with the help of designer Simon McCarthy and builder Sam McCarthy. As a structural engineer with extensive CLT experience on previous XLam projects, Julian Addington focussed on refining the design and assembly process to maximise the cost benefits and speed of construction available through the XLam building system. On completion, the Addingtons decided to take the property to market and a sale was made immediately.


Mastering the challenged site with pad foundations supporting steel posts, ties and bearers, the long-span CLT floor panels were then simply coach-screwed in place through the upper USB bearer flange. XLam provided the panels with extruded polystyrene sheet insulation factory-fixed to the underside. Timber plates were also pre-fixed to the panels along the bearing lines, to protect the polystyrene from crush during delivery and assembly and to provide direct fixing between the CLT and steel bearers. This system proved highly effective and made for substantial labour savings on site.

Walls of the single storey house comprised mostly open timber frame, with XLam CLT for feature walls and for the entire roof structure. The assembly process proved exceptionally fast because of the care taken in design and project organisation. Placing and fixing the floor and roof each took less than a day.

Although all the CLT is on display, the owners elected to use non-visual quality panels for the floors to allow the full character of Radiata pine to feature and to effectively disguise wear and tear.

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Customer Endorsements

“Many positive comments. Heidi and I are both thrilled with how it turned out. Despite the flat market in Christchurch the real estate agent was overwhelmed at every open home. Sounds like half the neighbourhood dropped in for a nosey”…………”I feel the style of construction here is the future of building in New Zealand by utilising our precious NZ timber resource, adding considerable value through prefabrication, and building in a way that’s fast, cost effective, sustainable and robust”.

Julian Addington