Mainstream volume housebuilders could benefit from the speed and performance of insulating concrete formwork (ICF).
ICF, also known as permanently insulated formwork (PIF), is an innovative modern method of construction. Led by the self-build and social housing sectors, the construction method consists of twin-walled expanded polystyrene (ESP) or extruded polystyrene (XPS) blocks, panels or composites, connected by plastic or metal connectors and then filled with ready-mixed concrete. The system combines the inherent strength and performance properties of concrete with the excellent thermal insulation properties of polystyrene.
For volume housebuilders, it’s the speed ICF can offer that is significant, with up to 4m2 per man hour. This equates to the ICF structure of a five bedroom detached house being built in just two weeks.
There is also minimum waste, as off-cuts from ICF block and panel elements are collected on site and recycled directly into the manufacture of new elements. ICF also has an inherent adaptability so contemporary architectural and traditional vernacular designs are easily accommodated. Any form of external finish, such as masonry, brick-slips, render, tiles or weatherboarding, can also be affixed.
With recent amendments to Building Regulations and sustainability assessment tools , all demand high levels of insulation and energy efficiency. ICF can provide U-values in the range of 0.11 to 0.35W/m2K.
In addition to high levels of insulation, ICF structures have very low air infiltration rates; almost all air infiltration is accounted for by window and door openings. As a result, there is very little heat loss due to air leakage.
Given the cost, speed of construction and performance advantages of ICF, this product can be added to the array of successful heavyweight solutions which currently make up some 90% of the market in England, and help to address the increased levels of activity.