im taking on the task of building a big 6x4x4 double walled smoker, now heres my question, insulation? is this a good enough insulation between the walls? Thermafiber® UltraBatt™ is a new residential and light commercial mineral wool insulation batt. UltraBatt is made with 70% pre-consumer recycled content and is fire resistant to temperatures over 2,000°F. UltraBatt provides thermal insulation, fire protection and sound control. Designed for Wood Stud applications R15 3.5" x 15" x 47" each batt 5 batts per package equal 24.5 sq ft Unfaced Mineral wool is more dense than traditional insulation batts, the added density improves sound control UltraBatt is ideal for walls between bedrooms, exterior walls, basement walls and ceilings, bathrooms, home theater walls and dividing walls in multi-family housing. Mold Resistant Easy to Install thanks ahead for any input givin!!!