This is a very long story but with interesting background for a pretty straight forward short question about closed cell odor. About 8 months ago we bought an old clapboard converted 2 story barn 1800 sf built in 1940’s. During last December, thermal imaging and air infiltration testing showed tremendous air heat loss through the walls, around windows and particularly at the corners of exterior walls. The inside walls were unattractive cheap pine paneling in bad state with holes, cut-outs, etc over the 60+ years of previous family living. . We removed some sections facing exterior to inspect and found the old fiberglass insulation had turned to black clumps, fallen and the exterior sheathing under the clapboard didn't have any plastic/tar barriers so you could see light through the seams of the plywood sheathing !!! We decided to remove all of the old interior pine walls and replace with sheetrock (cost savings) and we were recommended to to seal the exterior facing walls (2x4 construction) with 3" closed cell for both 1st and 2nd floor walls. At that point we also opted to convert the unconditioned attic to a conditioned space using 5" closed cell in the rafters. The installer said it would be better to also install a cardboard like material in between the rafters before applying the foam that would still allow airflow from the exterior rafter tails /eaves up each rafter bay under the roof sheathing up to the ridge vent. All of this was applied by an insulation only company with many years of experienced people. After the first 24 hours, no odors whatsoever and none since. Now the old barn was built on a slab on grade with fieldstone foundation except for one area where the grade slopes down so under a bedroom/bathroom about 12’ x 18’ there is a 3 foot deep crawlspace, with dirt floor surrounded on 3 sides with a 24” thick fieldstone foundation wall. This area in Fall, Winter and even with heavy Spring rains always appeared fairly dry but moisture was clearly a problem as the wood floors were warped in several areas. The rodents also had easy access to this space and was found to be the main route for them getting into the rest of the house. So, we put a vapor barrier over the dirt floor and poured a 4”-6” concrete rat slab and using same closed cell foam the company sprayed all of the stone foundation wall INSIDE the crawlspace with a few inches of foam. We ventilated the space for 24 hours via a large exterior crawlspace access door . Again 24 hours later no odor even as I crawled into the space. The floor joists in this crawlspace are from the old barn and they are an incredible 3 ½” X 12” running along the 12’ width span. The bathroom plumbing cold/hot pipes, baseboard water pipes and waste pipes ran in between these deep joists covered loosely only with old fiberglass wadding, so we removed the old fiberglass and had the company spray 4”-5” of closed cell up in between each floor joist to insulate the water and water pipes. No odor…. Now for the big ending…. We were adding a whirlpool tub and forgot to add the new drain waste line before spraying so we cut through the plywood subfloors and into one of the joist bays a few days after the closed cell was applied. No odor UNTIL we had to chop out the hard closed cell (4-5”) and boy did this stuff when cut up stink up the place. It was rock solid, nothing gummy to suggest it hadn’t cured but what a stink. So my question…. Does this suggest a bad application – maybe too much, too quick, too thick? I cannot smell anything in the crawlspace nor anywhere else before we started to chop out the recently applied foam between the joists. Thanks for your patience in reading my long story… any advice appreciated.