Paying Zakah for charitable projects

Q: The Committee for the Development of Al-Rawdah in Ha'il is seeking to widen the Muslims' passageways and the narrow streets in response to the request of the local residents. Narrow streets and passageways were the main reason for many children and old people losing their lives and being wounded in car accidents. Therefore, the Committee for the Development of the town is working to prevent the occurrence of such accidents and has plans to encounter this danger and save the lives of people from these hazardous streets and passageways. The entire members of the Committee, including Shaykh Sulayman Al-`Amir and the sender of this letter to your Eminence, exerted great efforts to raise people's awareness to the problem and to generously contribute to the accomplishment of this benevolent work. Many generous people assisted us in our project of widening the streets by donating some plots of their farms and parts of their houses, each according to his capability. The question is: some of the donors are not able to build a wall instead of the one taken from them during the work of expansion, or to rebuild a house to live in instead of their taken houses. They are too poor to even afford the cost of repairing a wall to shelter them and their families or to rebuild a house instead of the one they donated. We were embarrassed to pay Zakah (obligatory charity) for them in cash. Is it permissible to assign part of the money of Zakah to cover the expenses of repairing their walls or houses? The Committee is quite sure that the owners of these houses are in great need and have no source of income. Many of them are quite old people and unable to work? We hope that you will advise us on this matter.