Deck Ledger Board Flashing

[mathew stouffer]

Does the IRC specifically address deck ledger board flashing requirement.
Moreover, is it required if the deck has a roof.

Thanks Mat

[Randy Navarro]

R703.8 Flashing

"Approved corrosion-reistant flashings shall be installed at all of the following locations:

5. Where exterior porches, decks or stairs attach to a wall or floor assembly of wood-frame construction."

[Gunnar Alquist]

Does the IRC specifically address deck ledger board flashing requirement. Moreover, is it required if the deck has a roof. Thanks Mat

I seems to me that the purpose for the flashing is to prevent water from penetrating between the ledger and the siding. If the ledger has no way for water to get behind it then I cannot see why it would be a problem and I doubt I would mention it.

[BWarner]

Without the flashing, debris and moisture will get trapped between the ledger and the structure eventually rotting the ledger board and the rim joist and possibly corroding the fasteners as well.

[Matt Fellman]

Personally, I let it slide if/when there is a good roof overhang. By 'roof' I mean a real roof.... not some hacked up Home Depot fiberglass... I'm sure others will disagree and call it everytime they find it missing. There just isn't enough repeated water presence to damage the ledger if it's not exposed to the rain. How many times can someone pressure wash the deck?

BTW.... those simpson brackets are missing some fasteners... and I can't see for sure but make sure the ones in place are nails and not screws.

[Don Schlecht]

In my part of the world, the Texas Gulf Coast, all decks are constructed of treated lumber.

[Phil Brody]

Not needed if it is a real roof above. No water no problem.

[Paul Johnston]

Why do they have to be nailed and not screwed? Never heard that before.
Thanks

[Steve Frederickson]

In my part of the world, the Texas Gulf Coast, all decks are constructed of treated lumber.

I would hope that all exterior decks are treated, but doesn't matter if it's treated lumber. It still has to be flashed. The structure it's attached to isn't treated, and treated does not mean that it's indestructable. Water will still get into the bolted (hopefully) connections and rot out the the house rim board.

I agree that if there's an enclosed room above, no flashing is needed. However, if it's just a roof (no walls) I would say that flashing is required, due to wind-driven rain.

[Jerry Peck]

Why do they have to be nailed and not screwed? Never heard that before.
Thanks


Paul,

Only nails have been tested with the hangers.

Screws act differently and have different pull-out and shear strengths as well as they typically break or snap instead of bending. May grip the wood better, but what good is that if the head snaps off or the shank breaks?

Besides, they are not listed as approved fasteners for those hangers, so they are therefore not allowed - not without some engineering which says to use this type of screw with this hanger for this specific use.

[Jerry Peck]

I would hope that all exterior decks are treated, but doesn't matter if it's treated lumber. It still has to be flashed. The structure it's attached to isn't treated, and treated does not mean that it's indestructable. Water will still get into the bolted (hopefully) connections and rot out the the house rim board.

I agree that if there's an enclosed room above, no flashing is needed. However, if it's just a roof (no walls) I would say that flashing is required, due to wind-driven rain.

I agree with Steve, to do otherwise is to not acknowledge wind driven rain exists. :)

If the wood is outside - must be treated. It treatment depends on its use.

If there is a wood horizontal projection from the wall, it much be flashed above and over, whether that be trim or the ledger, the ledger needs it more.

If there is a room ... well, then it is not "outside" any more, is it? :D

[mathew stouffer]

Jerry,
When you say it must be treated. Would treating the would with a oil based product surffice.

[Michael Thomas]

From the 2009 Simpson General Catalog's "General Instructions for the Installer"

"Unless otherwise noted screws may not be used to replace nails in connectors unless approved and recommended by the Designer/Engineer of Record. Unless stated otherwise, Simpson Strong-Tie cannot and does not make any representations regarding the suitability of use or load-carrying capacities of connectors with screws replacing nails."

[Jerry Peck]

Jerry,
When you say it must be treated. Would treating the would with a oil based product surffice.


Matt,

No.

The wood would either need to be a naturally durable wood (as identified in the code) "or wood that is preservative treated in accordance with AWPA U1 for the species, product, preservative and end use. Preservatives shall be listed in Section 4 of AWPA U1."


- SECTION R319
- - PROTECTION AGAINST DECAY
- - - R319.1 Location required. Protection from decay shall be provided in the following locations by the use of naturally durable wood or wood that is preservative treated in accordance with AWPA U1 for the species, product, preservative and end use. Preservatives shall be listed in Section 4 of AWPA U1.
- - - - 1. Wood joists or the bottom of a wood structural floor when closer than 18 inches (457 mm) or wood girders when closer than 12 inches (305 mm) to the exposed ground in crawl spaces or unexcavated area located within the periphery of the building foundation.
- - - - 2. All wood framing members that rest on concrete or masonry exterior foundation walls and are less than 8 inches (203 mm) from the exposed ground.
- - - - 3. Sills and sleepers on a concrete or masonry slab that is in direct contact with the ground unless separated from such slab by an impervious moisture barrier.
- - - - 4. The ends of wood girders entering exterior masonry or concrete walls having clearances of less than 0.5 inch (12.7 mm) on tops, sides and ends.
- - - - 5. Wood siding, sheathing and wall framing on the exterior of a building having a clearance of less than 6 inches (152 mm) from the ground.
- - - - 6. Wood structural members supporting moisture-permeable floors or roofs that are exposed to the weather, such as concrete or masonry slabs, unless separated from such floors or roofs by an impervious moisture barrier.
- - - - 7. Wood furring strips or other wood framing members attached directly to the interior of exterior masonry walls or concrete walls below grade except where an approved vapor retarder is applied between the wall and the furring strips or framing members.
- - - - R319.1.1 Field treatment. Field-cut ends, notches and drilled holes of preservative-treated wood shall be treated in the field in accordance with AWPA M4.
- - - - R319.1.2 Ground contact. All wood in contact with the ground, embedded in concrete in direct contact with the ground or embedded in concrete exposed to the weather that supports permanent structures intended for human occupancy shall be approved pressure-preservative-treated wood suitable for ground contact use, except untreated wood may be used where entirely below groundwater level or continuously submerged in fresh water.

[Michael Koser]

There are other factors to consider even with a roof above. Can the rain blow in from the sides and saturate the area? I have seen a lot of rainwater blowing sideways with a good wind. There already appears that there is water staining at the lag bolts and nails. That ledger board also looks to be split in several areas. The band board is OSB and is subject to quick water damage. A lot of guys here say that they would not report. I for one would. Its not that hard to pull up one decking board and install a strip of flashing.

[mathew stouffer]

Jerry,
I got my threads confused. The question was regarding the exposed stand board under the deck in another thread. I am trying to figure out if I should mention anything about it. It is very dry in Utah most time and the deck is covered. But we do get a lot of snow.

[Jerry Peck]

Jerry,
I got my threads confused. The question was regarding the exposed stand board under the deck in another thread. I am trying to figure out if I should mention anything about it. It is very dry in Utah most time and the deck is covered. But we do get a lot of snow.


Matt,

I would, OSB is not designed to be left exposed to the weather and elements, even as protected as that is.

OSB probably has an Exposure 1 rating, meaning it is okay to be left exposed 'during construction until covered by following construction activities', which is usually taken as 'not longer than 6 months', less in harsh climates.

[Stuart Brooks]

It appears that a number of deck builders assume that vinyl siding is sufficient as flashing since they bolt the ledger board on top of the siding. Opinions?

[Steve Frederickson]

Assuming that the vinyl doesn't crack, it still doesn't prevent water from getting between the ledger and siding and into the bolt holes and rotting the rim board.

You need flashing that extends up vertically behind the siding and horizontaly over the tiop of the ledger