The raised seam type of roofing is a classification among metal panels; however, it also has several sub-classifications. Basically the difference lies in the type of fold that locks two sheets together.
- Overlap – One panel has a longer raised edge which then folds over the shorter edge of the sheet next to it. This is the simplest type of seam; however, it is not as durable since the two sheets are not mechanically locked together.
- Single Lock – In a single lock seam, one side of the panel has a short inverted "L" edge. The next sheet beside it has a longer raised edge that can wrap over the shorter one, creating a durable mechanical bond between the two sheets. This type of lock has superior resistance against wind uplift.
- Double Lock – The double lock seam is similar to a single lock except that the two panels are folded twice for better water resistance and improved durability.
- Batten – In a batten seam, the two sheets are spaced and held and sealed together by a third piece of galvanized sheet which caps on the top of the two panels and folds on the inverted "L" edges of both sheets in a manner similar to a double lock.
- Snap On – The snap on is a simplified means of locking the two panels together. One side of the raised seam is formed into a right triangular shape and the other side has a semi- rectangular shape. The two opposing sides are designed to interlock together without requiring any fold, making them easier and faster to install.
- Tee – The tee seam is similar to a batten except that there are no spaces between the two sheets. A third sheet runs through entire length of the panel and folds into a single lock on both the opposite sides, forming a letter "T."
Similar to a conventional roof, this system uses the same sub-components as a shingled roof. The metal panels have to be installed over a deck; however, spaced decking can also be used instead of a continuous since the sheets alone are already strong enough. An underlayment should also be used in between the panels and the decking to serve as protection from moisture since metal can easily attract condensation due to its low thermal protection. A type of asphalt-saturated organic felt is the most ideal choice for such applications.
In summary, a raised seam structure is one of the most durable systems currently available. It is ideal for areas where high wind is a common occurrence because of its high tensile strength. It is lightweight, easy to install, low maintenance, and comes in a variety of designs and colors. Hopefully this article has provided some helpful information regarding the various types and benefits of raised seam roofs!
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Do you need a professional roofer Houston company knowledgeable about raised seam roofs? Schulte Roofing at 800-367-7663 can help all greater Houston area customers with this particular type as well as with all other roofing needs!