Our objective is to construct a 3BHK, 1500 sqft residential house with all rooms attached in Kerala, India, adhering to a strict budget of 20 lakhs. The house will consist of a ground floor and one additional floor (G+1) and should include essential structural elements such as a Porch, Sitout, Combined Dining Sitting area, and three attached Bedrooms, along with a Kitchen. The first floor will house two of the three bedrooms.Please suggest best foundation method assuming loose filled soil, cost effective wall thickness and roofing methods with long life. Will be of great help if you can suggest the best possible way to approach this requirement.