Time for another look at Insulated Concrete Forms?

Time for another look at Insulated Concrete Forms?

They have their virtues, but concrete and petrochemical sandwiches shouldn't be on the green building menu.

Insulated Concrete Forms are a clever building system where two slabs of insulating foam are separated by plastic ties; you just stack them up, throw in some reinforcing bars if required, and fill with concrete. It makes a very energy efficient wall, the formwork is the insulation, and they are terrific in hurricane and tornado country. Many people consider them to be "green" because they provide such an energy efficient and durable wall.

Energy efficiency is a wonderful thing, but I have got into a lot of trouble with readers complaining that ICFs are polystyrene and concrete sandwiches, two materials that I am not particularly fond of. A typical comment was "apparently this d-bag has no idea what an ICF house is like in real life. Typical academic with no real world experience. Nice unimformed [sic] theories." Given that ICFs have their place (they make great basements) I have laid low on this subject for some years.

Now, writing in Passive House Plus, John Cradden looks at the use of ICFs in Passivhaus buildings. There is lots to like:

ICF is certainly finding its advocates among energy-conscious architects and designers thanks to certain advantages that enhance its thermal performance, including inherent airtightness, the virtual elimination of thermal bridging and the fact that its advertised U-values are reliably achieved.

Cradden does write a paragraph noting some caveats.

While ICF certainly has its advocates, others may baulk at the fact that it typically comprises two materials which can have comparatively high environmental impacts: ready-mixed concrete and polystyrene. Both materials have relatively high embodied carbon emissions, although the question of how green ICF is may need to be based on a systematic sustainability assessment of the whole construction. Such an assessment could determine the embodied CO2 of a material, among other parameters, including a full life cycle analysis.

Comparing apples to bicycles in a life cycle analysis/Screen capture

Source link