Deck Ledger Flashing
The Importance of Deck Ledger Flashing:
Recently I have been spending my time working up off of Monument Street performing exterior rot replacement in anticipation of having the house painted. This normally means going over the house with a fine tooth comb looking for problem areas to fix.
Deck ledger flashing problem areas typically seem to repeat themselves from house to house.
Deck Ledger Flashing Typical problem Areas Are:
1. Touching or low to the ground trim.
2. Horizontal surfaces: deck boards, railings, window sills.
3. Areas adjacent or below roof run off.
4. Flashing issues: missing, or improperly installed.
Below is a photo of the clapboards meeting the mahogany decking. The two story roof above does not have gutters and the client does not want them.
The problem is that the paint on the first and second clapboard courses continues to peel off due to the beating they take from the rain pouring off the roof and splashing off the deck.
The plan was to remove two courses of cedar clapboards and replace them with a 1×10″ pvc trim board that would weather the roof run off better.
Once the clapboards were removed we discovered rotted plywood sheathing and a deck ledger flashing problem.
The flashing used on this deck ledger was inadequate and basically is what we normally use to flash the top window trim boards.
The photo below shows the flashing extended above the decking approximately 1″. With all the rain splashing and snow build up
this flashing should extend higher.
In addition to the ledger flashing a second layer of tin, copper or rubber flashing should have run up the house behind and above
Another issue was that the original carpenters installed the Typar house wrap behind the ledger flashing.This wrap should be installed over the flashing so any moisture draining down it can end up on the outside edge of the flashing and not behind the ledger board where it could potentially get into the house framing.
We pulled off the rotted sheathing to discover that carpenter ants had started to chew into the structural rim joist.
The deck boards on the right of the picture is protected and
does not get the same abuse from roof run off.
~ concord carpenter