Since 1999 DW has implemented a programme for the preventive strengthening of existing houses in central Viet Nam. Roughly 70% of rural housing has been rebuilt by families since 1985, but the quality is poor and the result unable to resist the effects of storms and floods. DW helps families strengthen their existing home, at an average extra cost of 20% of the total value of their house. DW subsidises this up to 50%, the remaining costs are covered by family contributions.