My understanding is that it’s not bad when done correctly, but if they screw up the install it can be a nightmare and a huge safety issue. They screw up the mixture and now you’ve got extremely hard to remove foam stuck to everything that’s going to off gas dangerous chemicals for 20 years. It can go bad enough to completely condemn the home.
My understanding is that’s true of basically all insulation. Old structures were built with the assumption that they’d breath, and insulation wasn’t as important since they’d be heated by fireplace in the winter (either directly or using the fire to heat water for radiators) and air conditioning wasn’t a thing yet.
My understanding is that it’s not bad when done correctly, but if they screw up the install it can be a nightmare and a huge safety issue. They screw up the mixture and now you’ve got extremely hard to remove foam stuck to everything that’s going to off gas dangerous chemicals for 20 years. It can go bad enough to completely condemn the home.
IIRC it can also cause the structure to rot if they get the vapor barrier details wrong.
My understanding is that’s true of basically all insulation. Old structures were built with the assumption that they’d breath, and insulation wasn’t as important since they’d be heated by fireplace in the winter (either directly or using the fire to heat water for radiators) and air conditioning wasn’t a thing yet.