Subscribe to the channel: / @siteformlightsteelconstruc1884 In Todays video we will guide you through the steps on how to calculate purlin spacings for sheeting and also how to install the TH40 purlins on our light steel frame trusses For any business queries, please contact us at [email protected] Socials Instagram : / siteform_ Facebook : / siteform Website : http://www.siteform.co.za/