Hi, we are in the process of building an extension to our cottage which is 1 and a half times the size of the origional house(Extention is 60x15 square ft). So far we have the walls up, windows in and most of the roof timbers up. We were hoping to have the roof done some 2 months back, but the chippies just didnt turn up to do the job once the builder had laied the foundations and walls. Anyhow, we are nearing having the roofer put the tiles on and wanted to know what to do about the 4 green oak roof trusses we have-3 are internal and 1 will be exposed-plus the ridge beam is green oak. Once the roof is done do they need treating with oil to stop cracking etc as central heating will be installed very soon. I am doing all the internal work as Im in the plastering trade.