I see a lot of people installing the conventional metal building R panel on wood decks on homes. I thought that because of the thermal expansion of the metal panels that you had to use a different type of metal panel on wood structures. I had read somewhere that the metal panels expand 1/16 of an inch per every 8' of panel and over a period of time that it would work the fastner loose. I guess I need some advice on this matter.
Guest User
2001-11-22 19:14:20.000000
You only received part of the information. Both the wood and steel expand and contract it is just a differant rates.
The corrosion resistant metals used today do expand and contract approximately 1/16" in 8' however this is over 100 degrees F in tepreture change. Looking at a worst case scenario, a dark colour roof could reach 165 degrees F when in the dead of winter it coould go down to 0 degrees F. An average home would have a rafter length of 16'. The middle of the sheet would not move however each end could move a maximum of 3/32" however the wood shrinks somewhat as well so a 1/16" differantial movement could be expected. The fasteners today are designed to handle well in excess of this.
Hope this helps.
