Volunteers and staff from Greater Des Moines Habitat for Humanity are building a house at the Iowa State Fair, which began today. More than 350 volunteers will work on the house through Aug. 19. After the fair concludes, the house will be moved to its permanent location just blocks west of the fairgrounds. The home will later be purchased by a qualifying family with an affordable mortgage. The house is under construction on the northwest side of the fairgrounds, between Gate 13 and Grand Avenue. The last time Habitat built a house at the fair was in 2005.