Yes. Spray foam insulation can be applied to metal panels on open decking systems after the metal panels are installed, provided the following care is taken:
- Thermal spacers must be used on all metal purlins/framing to prevent rust or uneven color.
- All panels are properly installed and fastened securely
- No overspray of foam insulation gets onto the top side of the panels
- Spray is uniformly applied: non-uniform applications can cause thermal shock and loosening of fasteners, or potentially create uneven color.
- Insulation should be pH neutral (non-acidic and non-alkali) to avoid corrosion of metal panels.
- All structures and conditions comply with prevailing building codes.
- All proper surface preparation and application procedures are followed per manufacturer guidelines and per SPFA-134 linked here.
- If possible, apply foam in an inconspicuous area to check adhesion before applying to the entire job.
The Spray Polyurethane Foam Alliance, an association representing leaders in the SPF industry, has created a guideline for insulating metal buildings with spray polyurethane foam. It can be reviewed by clicking here. More information is available on their website at www.sprayfoam.org.