The modest scale of these simple yet detailed structures belies the expertise, highest quality workmanship and materials embedded in them. The double wall construction, lack of any thermal bridging, R 48 walls, R 56 roofs, .9 ACH50 (super tight for 2013 standards) led this project’s HERS rater, Home Energy Raters, to recommend us as the most energy conservation-conscientious builders in Lincoln to A3 Architects for the Old Sudbury Road project.