Floor

If you research container homes you will find only a bit of info on dealing with the chemically treated floor. Essentially the bad smell in most containers is the floor. My container contained Basileum and can be found on the placard on the door. It's a known cancer agent.

The active ingredient in Basileum SI-84 is Phoxim, an organophosphate compound.  Phoxim seems to be commonly used against ants and termites, and can be found under the brand name of Baythion produced by the Bayer Corporation.  The active ingredient in Radaleum FHP-60 is theta-Cypermethrin, a 2nd generation synthetic pyrethroid.  According to Wikipedia, Cypermethrin is found in many household ant and cockroach killers, including Raid and ant chalk. 

Both Phoxim and Cypermethrin are considered moderately hazardous (Class II) by the World Health Organization.  What differentiates these two chemicals for my purposes is their vapor pressures.  Phoxim has a vapor pressure of 2.63 mm Hg at 20° C, while Cypermethrin has a virtually nonexistent vapor pressure of only 0.0013 mm Hg at 20° C – more than 2,000 times lower.  Why is the vapor pressure important?  It’s easy to encapsulate the contaminated floors of a shipping container to eliminate physical contact, but it’s very difficult to block their vapors, if present, and their subsequent inhalation. 

The 2 main options are to encapsulate the floor with Epoxy, or to remove the plywood floor completely and replace. The main issue with the chemicals in the floor is the vapor pressure from the chemicals. Epoxy will seal it well. Almost anything else will not stop the vapor pressure. I decided to try a third option and use 1/2" PolyIso styrofoam to stop the vapor pressure of the floor chemicals. 

My reasoning is the foil layers of the styrofoam will control the vapors from the floor. So I layed the 1/2" Polyiso down and foil tape for duct work on the joints. Then the joist framing is laid on top of the PolyIso sheets and screwed down to the floor being careful not to suck the joist down too far. Laying a 78" level across the joist to keep level. Then space between joists is filled with 3 layers of 1" PolyIso and 1 layer of 1/2" PolyIso for a total of 3 1/2" the same as a 2x4. That gives an R value of 21.7 for just the joist thickness plus the 1/2" under for a total floor of R23.4. For comparison a typical 2x4 wall has R13 and a 2x6 wall has R19. 

The floor plywood was regular tongue and groove, glued and screwed down to eliminate squeaks later. The result after the floor and everything was finished is there is no smell from the floor at all anymore.

The steel is cut 2" below the inside floor height to account for the 2" steel frame resulting in a finish height of the steel the same as the floor inside. The door then sits on both surfaces and has excellent support. The gap under the door was filled with spray foam before setting door since it would be inaccessible after door was installed.