a. It is simple type of single roof in case of pitched roof. It is also known as the pent roof or Aisle roof.

b. In such types of roof one wall is carried up sufficiently higher than the other one to give necessary slope to the roof.

c. The rafters are suitably secured on the wall plates and caves boards, battens and roof covering are provided as shown in fig.

d. Maximum span of this type of roof is 2.5m. Lean to roofs are usually attached at the main entry of the house so as to obtain sheds so that direct heat radiation from the entrance area can be prevented and inside rooms remains cool. Hence lean to roofs are attached to main buildings, verandah, out houses so as to obtain sheds.