CEDAR RAPIDS — In its efforts to reduce chronic homelessness, Willis Dady Homeless Services has acquired a house it plans to add to the stock of housing that meshes affordability with social services.The group took possession this month of a home in the 1600 block of Washington Avenue SE in Wellington Heights.Unlike a homeless shelter where stays typically are limited to a time period, permanent supportive housing like this is seen as a long-term affordable housing option where tenants typically pay below-market rental rates.