There is a difference of opinion in the market with screwing to the wall or gluing to the wall. The PIR foam is moisture resistant, unlike other composite foams, so condensation will not harm it. But, if you want to keep the heat transfer to the absolute minimum, we highly recommend that you glue directly to the FRP. Sikaflex holding strength is 250 lbs. per square inch, which is way stronger than a pin-pointed load that a mechanical fastener can hold. Gluing to the wall also reduces vibration between the cabinet and the wall. To make this even easier, we’ve designed an “L” extrusion for gluing to the wall with built in glue pockets and mechanical attachment that can withstand 400 lbs. of static load each. The composite sheeting (AZDEL Z) on the inside panel walls provide an opportunity to screw to the walls as well with sheet rock style hardware. You decide!