Compared with the traditional insulation material , like glass wool, foam ,rock wool , our multi-foil insulation material can give you a very high thermal barrier rate ,7.17M2.k/w . the mateiral can not only seal your roof from the wind and dust as a envelop ,but keep the inside air flow smoothly , providing you a good ventilation living surrounding . after installing , your roof will retain dry and warm in winter , while prevent loft overheating in summer . The thickness is 38mm and the beams and rafter can be lefted exosed , so our material will save valuable living space in the attic .