Several changes have been made, and others are under consideration, which will have an important effect on the cost of slab-on-ground construction subject to FHA Minimum Property Requirements. Already written into new Minimum Property Requirements are three recommendations that seem bound to result in economies: a «-inch tolerance is now permitted in a 4-inch thick stab. This change will permit the use of 2-by-4 forms, and might reduce the slab concrete for a 1000-square foot house by as much as 1 « cubic yards. Asphaltic coatings are no longer required to protect perimeter insulation against moisture. New MRP's require that perimeter insulation be "not permanently harmed by wetting or by contact with wet concrete mix." It is believed that this change could mean a savings of up to 8 cents per perimeter foot. The new MPR's turn thumbs down on the use of waterproofing admixtures as a means of correcting deficiencies that can be prevented by sound construction practice. They approve, however, the used for air-entraining agents that result in improved durability, workability, and freezing resistance.