Room for Improvement: Air Tightness in Timber Frame Construction

Abstract

Timber frame construction in Ireland is beginning to gain significant ground on traditional block built construction. This is in part due to developments in timber frame practices. The application of an air tight barrier is now a common component in the construction of a typical dwelling. With much emphasis placed on energy efficiency and increased insulation value within the home, air tightness is a key factor in the continued development of these areas. In March 2008, Part L of the National Technical Guidance Documents was updated to include the requirement of a mandatory air infiltration test on all new dwellings in Ireland. In December 2011 the pass level was lowered to further reduce CO2 emissions. This paper presents a research study into the Irish timber frame construction industry which addresses the need to accommodate greater air tightness capabilities in a typical dwelling. This research focuses on the jointing technique between closed panel timber frame members and the ability to produce an air tight joint without compromising its structural strength. Ensuring that the main fabric of the building is correctly sealed not only prevents air escaping but also assists in the wind tightness of the dwelling along with significantly improving thermal comfort. The preliminary findings identify the upgrading of basic jointing techniques as essential in the continuous development of air tightness in timber frame construction. It is envisaged that the findings will have a positive impact on timber frame construction in Ireland and beyond.