The Grameen Bank is a co-operative non-governmental association that first began a loan programme, without collateral, for the rural poor to help them initiate income generating schemes in Bangladesh. This proved successful and the incomes of the loan recipients rose, and most were able to repay the bank. Encouraged, bank officials decided to extend the bank's support to house-building, and  offer credit to its shelterless members, 84% being women, to build flood and water resistant modest houses.

Structural system of basic units.
Structural system of basic units.

There were two types of housing loans by 1989 - the basic housing loan of 10,000 Bangaladesh Taka and the standard housing loan of 18,000 Tk. For the basic housing loan, which was taken by the majority of borrowers, the Grameen Bank stipulated an area of at least 20m2, constructed with 18 corrugated iron sheets and four reinforced concrete posts. The loan also included a provision for the purchase of a latrine base and four latrine pit liners.

The columns and latrine kits were manufactured by the Grameen Bank using moulds which can easily be transported to a different location
The columns and latrine kits were manufactured by the Grameen Bank using moulds which can easily be transported to a different location: The corrugated iron sheets are bought on the local market according to the quality specified by the bank. Corrugated iron, though processed in Bangladesh, was essentially an imported material and as such, it represented a drain on the national economy. Other materials - such as the necessary additional posts of wood, bamboo or concrete and bamboo matting for the walls - were bought by the loanee as he or she wishes and can afford. All the materials were familiar and readily transportable by boat, cart or rickshaw, and no technical expertise was required in constructing the house.
Along with loans of approximately US$ 350 at 5% interest, each borrower received four concrete columns, a prefabricated sanitary slab and 26 corrugated iron roofing sheets
Along with loans of approximately US$ 350 at 5% interest, each borrower received four concrete columns, a prefabricated sanitary slab and 26 corrugated iron roofing sheets: Other building materials were procured as needed. The structural system was based on a standard module, and the pre-cast building materials were mass-produced off site and made available to the self-helpers at low prices. The families constructed the houses themselves.  

The overall responsibility for design of the house rested with the loanee, and there was a considerable scope for choice. The loanee decided how to fill the walls, the number and type of doors and windows, the height of the plinth on which the house stood or whether to use a plinth at all; and the composition of the floor, where most of the floors were made of rammed earth. While the buildings adhered to the local architectural character - including hipped or gabled roof forms, no two loan houses were exactly the same. Even the position of the concrete columns has in some cases been changed, to support the roof truss.