For example, a 4x8 polyisocyanurate board from Johns Manville costs about $26, so you can measure the square footage of your exterior walls to get an idea of how much the materials will cost.

When these products burn without enough air, the toxicity is even greater. PIR (polyisocyanurate) is based on polyurethane, and gives off hydrogen cyanide and carbon monoxide when burning.

Rigid foam insulation is made from polystyrene, polyisocyanurate, or polyurethane and comes in board form. It provides excellent thermal resistance and is used in walls, roofs, and foundations. Rigid ...

The insulation mostly used was RS5000, a polyisocyanurate foam made by Celotex (which releases toxic gas when it burns), with some made by Kingspan. Because of all this, "compartmentation" – the ...

Extruded polystyrene, or blue board, is more water-resistant and durable than beadboard with a high R-value of R-5. However, like beadboard, it's a fire hazard. Polyisocyanurate is the third type of ...

Dr Phylaktou believes the configuration of the cladding and the foam - known as polyisocyanurate (PIR) - was "optimum for vertical fire spread". "This explains the speed of the fire propagation.

The greatest toxic hazard in almost all fires is due to carbon monoxide," he said, "There is no evidence to suggest that PIR (rigid polyisocyanurate) presents any special hazard in terms of toxicity.

When it comes to home improvements, floor insulation often takes a backseat to more prominent upgrades like loft insulation ...

If your home is listed, or in a conservation area, planning rules may not allow external wall insulation. The most thermally efficient EWI systems typically use plastics such as expanded polystyrene ...