Jake White from Ecotecture shares the story of The Curly House, an award-winning project that was built using insulated concrete forms (ICF). He explains what an ICF is, why there are benefits in terms of speed of construction and durability, and why most concrete structures have the potential to be extremely airtight.
Interview with Jake White
Jake White has been a director at Ecotecture for 10 years now.
His interest in low energy buildings and sustainable design was brought about by a desire for improvement, having seen how bad the quality of workmanship and lack of understanding was in the “house bashing” industry.
Concrete’s Bad Reputation is Not Always Deserved
The manufacture of concrete and the resultant CO2 emissions often give it a bad reputation. Jake feels that given its durable, dense, long-lasting structure, this should not be the case for buildings that are designed to last generations. In producing buildings of this quality he is disconnecting his clients from the effects of fuel hikes and fuel poverty.
Insulated Concrete Formwork Does Not Prevent the Benefits of Thermal Mass
Traditionally the thermal mass of concrete has always been exposed so it will re-emit the heat at night time that has been absorbed during the day. The experience Jake has had of using the insulated concrete formwork is that there is a lag in the heat being re-emitted and thus the benefits from it last longer than the single day.
Essentially Jake expects the temperature of the concrete core to remain stable and consistent with the interior temperature of the space.
A Single Construction Method can be Best for Cost and Energy Efficiency
This was certainly the case for the Curly House, which has a beautiful but very exposed site. Jake suspects that over time if different construction methods had been used, such as a concrete basement and timber frame, there would have been jarring against each other resulting in the airtightness being compromised.
Concrete was deemed to be the ideal material to match the undulating forms of the building with those of the landscape.
The Key to Insulated Concrete Formwork Longevity is a Dry Central Core
A tanking treatment is used on top of the regular foundations to prevent moisture from rising.
There are Key Features to Look for When Selecting an Insulated Concrete Formwork Product
- The adaptability
- The quantity of details they have and have thought through
- The technical support
Reduce Waste by Selecting the Right Thickness of Product for the Job
Even within a single project there are different thicknesses of concrete needed, dependent on the load they are retaining. The products are designed so that you only have to use the thickness that is required for the particular task.
The absolute minimum width required cannot always be achieved, given the limitations and requirements of the pouring process.
There is Flexibility in Terms of How Insulated Concrete Formwork can be Rendered
Due to the excellent levels of airtightness almost any interior or exterior finish can be applied. It is one of the rare products which doesn’t need a wet plaster finish on the interior for the purpose of achieving airtightness.
Great Results can be Achieved if Attention to Airtightness is Given
Jake has seen examples of buildings using insulated concrete formwork where, even without trying, adequate levels of airtightness were achieved. With these results almost being realised by accident it wouldn’t take a great deal more effort to achieve the Passivhaus standard.
Tapes and Membranes are Still Required for Windows and Doors
For buildings that have a full insulated concrete formwork, the only areas vulnerable to air leakage are around the windows and doors so tapes and membranes need would need to be used.
High Quality Design Requires a High Quality Contractor
The Curly House benefited from having a contractor with lots of experience in the systems being used. There had been many challenges but the level of attention to detail and capabilities of the contractor resulted in the high quality design being reflected in the construction.
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