Did the contractor just ruin my vaulted ceiling with open cell foam?

In Massachusetts, that open cell install is almost certainly going to fail code on R-value alone, never mind the moisture risk. You're looking at about R-3.7 per inch with open cell versus R-6.7 with closed cell. Unless those scissor trusses are incredibly deep, you likely aren't hitting the required R-value for a vaulted ceiling in our climate zone. The building inspector is going to look at the energy specs on your permit and then look at that soft, spongy foam and shut you down during the insulation inspection.

The bigger issue is the vapor drive. Open cell is vapor permeable. In a MA winter, warm moist air from inside your house will migrate thru that foam, hit the cold roof deck, and condense into liquid water. Since it's packed tight to the deck, you're basially trapping a wet sponge against your plywood. Without a dedicated **vapor retarder**, you’re looking at deck rot within a few seasons. This is a classic recipe for a mold factory.

You need to check the contract immediatly. The cost difference between a set of closed cell and open cell is massive—we're talking thousands of dollars in material alone. If they charged you for closed cell and sprayed open cell, they just pocketed a huge margin at your expense.

If you don't want to rip it all out, the only real way to save this is installing a high-end smart vapor retarder like **Majrex** over the face of the trusses before the sheetrock goes up. This lets the assembly dry out but keeps interior moisture out of the roof. But honestly? If the plans specifically called for closed cell, the contractor needs to make it right. Don't let them talk you into vapor retarder paint; it's rarely applied correctly enought to protect a vaulted assembly in the Northeast.

I'm just starting to look into insulation for my own place, and that sounds like a total mess. If they actually have to rip it all out, what does that do to the wiring you just put in?

I’d be so worried that scraping all that foam off would nick the wires or pull things loose. Is it even possable to get the wood deck clean enought for the closed cell to stick properly after it's been covered in the open cell stuff?

Scraping that deck clean is a nightmare. If they try to spray closed cell over the residue of open cell, you’re going to have major adhesion issues. I’ve seen crews spend days with wire brushes and still fail to get a clean enough surface for the new foam to bond properly.

Another thing—open cell is a total sponge for bulk water. If you get even a small roof leak, that foam will hold the moisture against your plywood for months without you knowing. Closed cell doesn't have that problem. You paid for a high-performance system, don't settle for a setup that coud rot your roof from the inside out.