How To Structure Metal Roof Insulation
Metal roof insulation aids in getting rid of common problems with roofs like condensation and heat loss. Metals conduct heat well, and metal roofs help in heat transfer whenever there is a difference in temperature between inside and outside the roof. In a similar fashion, when there is a sudden cooling, water may condense upon metal panels. Insulation prevents this from happening. There are various options when it comes to metal roof insulation.
Fiberglass batts or glass mineral wool insulation is commonly used for metal roof insulation. The fiberglass batts act as a barrier between the roof and interiors of your building. These batts, when placed side by side on the rafters, don’t form a solid and continuous barrier allowing air to flow freely through the gaps and leading to heat loss.
Insulation batts themselves leak heat, albeit a bit slowly. Batts also require a vapor barrier. Batts cannot be positioned under metal roofing because condensation that results will seep through the metal roof insulation material and damage the roofing material. Water transmits heat and when it seeps through into the batts, you may need to replace it. That’s why the gap of 15 cm. between the roof and the insulation barrier can help prevent water from condensing.
Still, there will be some heat loss. This option is therefore not ideal for metal roofing systems, because both the major problems with this kind of roof – condensation and heat loss. Such an intricate woven fiberglass metal roof insulation system will be expensive and stretch your budget for construction or repairs.
Polyurethane spray form is another type of metal roof insulation. When you spray the bottom of the metal roofing material with a layer of polyurethane foam, it prevents problems of very cold interior temperature during winter, and hot summers inside the building. Polyurethane foam is a spray and not a physical barrier like the batts. It gets into crevices and gaps, forming a total heat seal so that thermal leakage is no longer an issue. It is better for metal roof insulation than batts. How thick the foam you spray in determines the U rating of the roofing insulation. This indicates the thermal value of your roof, with thicker layers providing better insulation.