I think that the GBA web site sums it up pretty well. Are you looking for a simple answer to a complicated question?

As with so many things, the answer is far from clear. Opinions differ. To my knowledge, neither the pro nor the con argument has a convincing and scientifically documented story to tell.

Your decision is irreversible. There are alternatives to spray foam. If you want to be SURE to not have a problem with your family, go with one of the several alternatives and avoid the controversy AND the potential risks.

lawsuits come from mix of spray foam not being
correct. this causes strong offgasing of the product.
other problems it causes is less adhesion of
the product & excessive shrinkage.

shop for foam companies before hiring one if
you chose foam. the lowest bid or the highest
bid is not an indicator of experience & finished
product.

best of luck.

Thanks for your comments !!

Mike Holmes of Holmes Inspection TV Show makes the spray foam look so good and so easy to install, but that guy can fix anything.

"Mike Holmes of Holmes Inspection TV Show makes the spray foam look so good and so easy to install, but that guy can fix anything."

And he gets as many takes as needed for the show.

I think Mike Holmes gets a little carried away with his spray foam insulation.

Even a thin 1/2"-3/4" layer of rigid foam board on the outside before the sheeting and siding with a tyvek housewrap or equiv. makes a huge difference. I would even say the housewrap and sheeting/ siding combo is waay better than just the siding. So minimum one layer of housewrap, one layer of plywood and outer layer of hardyboard or siding and I am not talking vinyl siding. I think the latter would be the minimum if you was going for efficiency.

Caulk and lots of it will be your best friend and when applied as the house is being built saves a ton of time compared to doing it after insulation is in and the house is being lived in.

Even a thin 1/2"-3/4" layer of rigid foam board on the outside before the sheeting and siding with a tyvek housewrap or equiv. makes a huge difference. I would even say the housewrap and sheeting/ siding combo is waay better than just the siding. So minimum one layer of housewrap, one layer of plywood and outer layer of hardyboard or siding and I am not talking vinyl siding. I think the latter would be the minimum if you are going for efficiency.

Caulk and lots of it will be your best friend and when applied as the house is being built saves a ton of time compared to doing it after insulation is in and the house is being lived in.

My personal preference is that I don't want foam anything in my house. One thing not previously mentioned is that many types of foam are highly flammable and produce dangerous fumes and high temperatures when they burn.

Wood is flammable enough, I wouldn't want to feed a fire any more than is necessary. There are reasonable alternatives to foam that avoid the fire and health risks that can be faced.

snidely,

You said, "One thing not previously mentioned is that many types of foam are highly flammable..."

There are foam products that are approved for use in residences that are "highly flammable?" ????

Most residential building codes require that there be a fire-rated barrier between the foam and the living space: drywall or an intumnescent coating.

The link has some good points about the small % of jobs that go south and why.
The bad ones seem to be a combo of unsuitable (cold) weather, poor supervision,
don't care workers who spray too fast and too thick with material that isn't hot enough to meet the spec, etc.

A good honest company with well maintained equipment and skilled operators is a must. It will be expensive.
Check multiple references thoroughly before anything else.

Here is a link that might be useful: Spray foam short comings

Good question. Most spray foam mishaps comes from people misusing DIY spray foam kits. These are cheaper but these come in two parts and must be mixed precisely to ensure the foam comes out evenly. Unfortunately, one of the materials is thicker than the other, so maintaining a homogenous mixture can become nearly impossible. This makes it easy to mess up, which can be dangerous. People should look here for more info on spray foam and a list of questions you should as a contractor.

The spray foam I've used is flammable, but certainly not highly flammable. It will burn if there is a flame applied, but snuffs right out as soon as the flame is removed.

If you use spray foam to insulate a new house, in the walls it will be encapsulated by the drywall on the inside and the sheathing on the outside. If its used in the attic they will spray it with a fire/thermal barrier. It is effective and should be completely safe if done by a competent contractor.

If you have a contractor spray foam an entire house you will not get Harry Handyman doing the job, because it takes multiple crew members and high quality equipment to do the job quickly and effectively. If there are issues with the mix that cause problems with the foam it will be evident before the walls are closed up. If done properly you should not have any odor after about 24 hours.

Bruce

Yes, absolutely. If you put spray foam insulation in a building, it needs a thermal barrier. That's what separates it from the occupied spaces. If there's a fire in the building, a thermal barrier keeps the combustible spray foam from the flames to increase fire resistance. The International Residential Code (IRC) and Internation Building Code (IBC) both include requirements for thermal barriers. An experienced contractor would be able to tell if there is anything wrong with the job before they close up. That why its important to ask your contractor questions. There is a site for Windsor spray foam insulation that has a good list of questions for a contractor so you can hopefully avoid any mishaps like that.