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TOPIC: Standing Seam roof

Singel lock vs Double Lock

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We need to replace the roof on our log home and are thinking about having a standing seam metal roof installed. We have been told that there are 2 types of locking systems for the panels; single lock and double lock. Can you explain the difference and the pros and cons of each. We have a 12/12 pick roof. Thanks
Guest User

9/7/2004
"Double Lock" is referring to a system that is mechanically seamed with a seamer once the pans are fastened into place. Although this type of system can be used on any roof pitch, it is most common on lower pitch roofs of less than 3:12. The single lock or "snap lock" systems are all applicable for a roof of 12:12 pitch.
Guest User

9/7/2004
Double lock is not snap lock unless you are referring to someones product name. Double lock refers to the seams being folded over on top of each other or locked together twice as in traditional hand formed tin or copper roofs (hence double). Single lock refers to one layer folded or seamed in a hook like fashion ofer an adjacent pieceand is some times referred to angle seam. Either type could be an end lap or the main side laps of the panels. Either double or single could be eithe hand seamed on softer materials or on either soft or hader materials such as steel seamed with a seamer in one or two steps depending on the equiptment available. When generally speaking of double lock as the type of panel or system they would be referring to the sidelaps.
Guest User

1/11/2005
There are seamed and unseamed "standing seam" roofs. Also there are flange fastened which lay on flat decking and there is clip fastened which stands the roof off the deck. Then there are fixed clips and floating clips that allow the roof metal to expand and contract. The lower the slope then the higher the seam needs to be and the lowest slopes should have the seam hemmed with a seamer. I would look at why your existing roof failed and take this opportunity to correct any deficiencies in the roof assembly. The building codes now call for vented roof assemblies in residential construction. Assuming that you have vaulted ceilings, you need to provide a minimum of 1" vented air space in the US and and 1 1/2" in Canada. If this is not already provided for then choose a metal roof system that will.
Allan Reid
Dura-Loc Roofing Systems, Inc.

1/12/2005