Creating the perfect curve
Curves in architecture can look stunning, but they also present a unique set of challenges to create. In this post, Justin Price explains how a flawless curved finish was achieved for Moneypenny’s new £15m headquarters.
If done well, architectural curves can truly transform and soften a building, but if done badly, they can look incredibly clunky. Both the materials you use and the skill of the tradesmen are paramount in achieving that effortless, sweeping finish that a curve should create.
In September 2016, Wrexham-based telephone answering firm Moneypenny moved into their new headquarters. Aliva UK was privileged to work on the beautiful curved façade of this unique building, designed by AEW Architects.
The headquarters were built with sustainability at the heart of the brief. By using rainwater recycling, solar energy, ground source heating and natural ventilation for climate control, the company aims to be almost entirely self-sufficient. The thermal efficiency offered by Aliva’s Termok8 insulated render was therefore a key consideration in the architects’ selection process for the finish of the building.
Insulated render is made up of several layers. It starts with an insulation layer, such as mineral wool or expanded polystyrene, which is fixed to the building with adhesive or mechanical pins. Layered on top of that is the render, which is usually added in two layers to achieve a profile of about 6-7mm. Last but not least, the finish is added – in this case to create a crisp, textured façade.
5,000sqm of Termok8 created the final façade at Moneypenny which you can see in the images. On the face of it, render could seem like one of the simpler building materials with which you can create a curve, but look into the detail and you’ll find the product and processes used can make all the difference to the quality of the finish.
The first challenge with this particular project was the number of curving walls, and ensuring that the curves were created to perfection.
The choice of insulation is particularly key here. Expanded polystyrene is the correct material to use, as it allows for its face to be ‘rasped’ or sanded down to create the curve.
It is crucial to ensure that the curve is created before applying the base coat and that the base coat is then smoothed to follow the curve. Each process follows the other and if one isn’t right then it will show up on the final texture application.
Another challenge with insulated render is that it is often possible to see ‘day joints’ in the finish. This is where there is an obvious join between where a contractor finished for the day and then began again the next. For this building, which required a flawless finish, it was vital this was managed correctly.
There was also the additional consideration that there were many large expanses of façade in this project – up to 14m in some areas, which added to the difficulty of achieving a consistent smooth, crisp look.
These challenges would be problematic even on your average straight-sided project, but on a curved design it’s particularly demanding.
The finish we achieved for Moneypenny was created using two mast climbers, which enabled us to produce a 12m day joint. This was made acceptable both because of the large openings in the façade and due to the flexibility of the Aliva UK base coat and textured finishes.
We’ve also created a finish that will last, as well as provide excellent insulation. Our Termok8 system has both self-cleaning and anti-fungal properties which will keep those curves pristine for many years to come without the need for endless cleaning, adding to the environmental sustainability of the building.
Ultimately, this meant we were able to achieve the architect’s vision for the façade – smooth, elegant curves and a crisp, environmentally-friendly finish with no clear breaks or joins.