Islamic House Financing is Shariah (Islamic Law) Based modes of financing. There are different modes of Islamic House financing being used in different countries. The Objective of this research is to highlit the different modes of Islamic House financing i.e. Murabha (Bay Bi thaman Al Ajil), Diminishing Musharkah, Istisna and Ijarah. The second part of this research has covered the practice of Pakistan's largest housing finance institution the House Building Finance Corporation, as a case study. In this section all products of House Building Finance Corporation will be examined in Sharia perspective, especially Ghar Aasan (Flexi) scheme. The research also examines the practice of Ghar Aasan scheme and concludes that the model of Ghar Aasan (Flexi) scheme is different from conventional house financing and is based on diminishing musharakah. But there are some Sharia issues in implementation of diminishing musharakah. The research escorted the writer to darw out recommendations andimplications in the last part of this research.