NHBC Warranty on New Builds: All New Build properties are issued with 10-year NHBC guarantee, the Majority of House Builders and Developers Will advise against New Homeowners Loft Boarding a New Build, the reasoning behind this is that historic methods of Loft Boarding a New Build, prior to the introduction of the Construction Certified LoftZone Raised Loft Boarding System would require Loft Insulation to be either removed or excessively compressed.