Underlay bitumen membranes are used for pitched roofs as an underlaying waterproofing layer for roofing shingles and other roofing materials. Difference between the external and internal temperature leads to the formation of ice on the roof surface, whereby water can penetrate. Underlay material is a reliable protection during the formation of ice on the roof. In case of the rain with strong wind is possible the penetration of moisture under the top layer of the roof and the occurrence of leakage in exposed locations. Use of underlay materials helps to prevent cases of leakage roof protects roofing pie.