Mark Magennis Technical Services Manager, Unilin Insulation. Mark joined Xtratherm, now Unilin Insulation, back in 2003 and leads the Technical Team for the UK and Ireland where he manages both technical support services and training. Mark specialises in thermal bridging, building energy performance and sustainability including life cycle analysis. He and his team regularly support self-build projects, advising on both regulation and legislation issues along with optimum fabric choices on projects.