How do I Mount a Deck Ledger Over Zip System R-Sheathing?
The thickness of the foam insulation will dictate whether you should use a standard fastening schedule or get advice from an engineer.
Q:
I’m installing a deck ledger on a new house where Zip System R-Sheathing has been used. Is there a special mounting system for installing a ledger with this type of sheathing?
Dan Crouse, Redding, CA
A:
Editorial adviser Mike Guertin replies: Huber’s Zip System R-Sheathing has rigid-foam insulation bonded to the back side of the structural panel and comes in two product thicknesses: 1 in. and 1-1/2 in. (A thicker version is being developed but isn’t yet available.) The short answer is that if the walls are sheathed with the 1-in.-thick version, you can mount the ledger using the IRC fastener schedule and most major screw manufacturer’s products. This is because the IRC has a maximum 1-in. limit between the back side of the ledger and the face of the rim board.
If the wall is sheathed with the 1-1/2-in.-thick version or the new, even thicker version, you can’t use the prescriptive code table, and your inspector may require that an architect or engineer design an attachment system. If that isn’t a viable option, there is an alternative deck-mounting system. The Maine Deck Bracket costs $29, has an ICC-ESR (meaning it has been tested for code compliance), and works well with thicker sheathing. Because these brackets mount directly to the rim board by way of a hole cut through the wall sheathing, they can accommodate up to 3 in. of thickness.
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View Comments
We had an engineer approve an attachment method where we run 1/2” threaded rod through the ledger and the rim joist with a pocket for brick (and air gap) between the ledger and the sheathing. Two pieces of 1/2 rod, one above the other, every 24” with a 3” square washer and nut on both sides of the ledger and rim band to set spacing. Then we can build the deck and the brick layers can work off the deck once the get to it and just set brick down into the pocket and it is continuous.
What was the other alternative deck attachment you showed from either the deck expo or IBS?