Shouldn't the IRC Require Flashing for Deck Ledger Attachment in Section R507?

[jar546]

There is a mention of flashing for exterior decks in R507 but it only mentions minimum thickness and type of material, not that it has to be done or how it must be done. The roofing sections of the code are very good about this. I am surprised that as many revisions in R507 since its birth as a new section did not bring forth this requirement.

There are two figures, one shows what I can assume is flashing and the other figure calls out flashing but does not show it.

I am surprised that one of the major reasons for deck collapses is the failure at the band to ledger connection, most often due to rotting from a lack of flashing is not prominently listed as a requirement in R507. This is why I have always been a fan of the AWC DCA-6 manual which not only stipulates corrosion-resistant flashing but also requires stainless steel connectors for all decks built within 300' of salt water.

At one point Pennsylvania had put together a fantastic deck program based on the AWC DCA-6.

R507.2.4 Flashing.​

Flashing shall be corrosion-resistant metal of nominal thickness not less than 0.019 inch (0.48 mm) or approved nonmetallic material that is compatible with the substrate of the structure and the decking materials.

 

[ICE]

TABLE R507.9.1.3(1)
Footnote a. Ledgers shall be flashed in accordance with Section R703.4 to prevent water from contacting the house band joist.

 

[jar546]

TABLE R507.9.1.3(1)
Footnote a. Ledgers shall be flashed in accordance with Section R703.4 to prevent water from contacting the house band joist.

A footnote? Footnote "b"
This should have its own section that is prominently displayed and not hidden in a footnote like a secret or at the very least in the code like this:

R507.9.1.1 Ledger details.​

Deck ledgers shall be a minimum 2-inch by 8-inch (51 mm by 203 mm) nominal, pressure-preservative-treated Southern pine, incised pressure-preservative-treated hem-fir, or approved, naturally durable, No. 2 grade or better lumber. Deck ledgers shall not support concentrated loads from beams or girders. Deck ledgers shall not be supported on stone or masonry veneer. Ledgers shall be flashed in accordance with Section R703.4 to prevent water from contacting the house band joist.

R703.4 Flashing.
​

Approved corrosion-resistant flashing shall be applied shingle-fashion in a manner to prevent entry of water into the wall cavity or penetration of water to the building structural framing components. Self-adhered membranes used as flashing shall comply with AAMA 711. Fluid-applied membranes used as flashing in exterior walls shall comply with AAMA 714. The flashing shall extend to the surface of the exterior wall finish.

 

[ICE]

Even a blind squirrel finds an acorn now and then.

Footnote a. You don't have footnote b. because the hurricanes blow the snow north.


I was going to add that only a complete idiot would place ledgers without flashing. Then I remembered an apartment complex with a hundred rotten balcony ledgers that were not flashed. The idiot part of that was that the supposed fix didn't have flashing either and it was an engineered plan... approved by the AHJ.

 

[jar546]

Even a blind squirrel finds an acorn now and then.

Footnote a. You don't have footnote b. because the hurricanes blow the snow north.

View attachment 12197

You are behind a few code cycles.

 

[ICE]

You are behind a few code cycles.

Always will be.

 

[redeyedfly]

A footnote? Footnote "b"
This should have its own section that is prominently displayed and not hidden in a footnote like a secret or at the very least in the code like this:

I grew up building single family under the UBC. Everything that applied to me was in the footnotes!!

I learned that you ALWAYS read ALL the footnotes

 

[Inspector Gift]

Yes Sir! Deck collapses are a real problem. One retirement community in Central Montana had several decks ledgers fail due in large part to there being no flashing at the wall connection. As Building Official, I was pulled into the legal fray and verified the builders did not comply with the flashing requirements adopted at the time they were constructed. Thankfully, it wasn't any fault of our department due to the policies in effect long before I was hired. And thankfully, there were no fatalities or injuries.

In the jurisdiction where I work, we have adopted and enforce the deck ledger flashing method detailed in the FEMA Technical Fact Sheet No. 23. (attached below).

 

[Robert]

All of these flashing details assume the structure has sheathing behind the siding or stucco. What do you do when you have a structure with wire backed plaster (or wood siding attached directly to studs) and no sheathing (typical 1950's post war homes)? Seems too invasive to open up a large chunk of wall instead of just lagging into the rim joist and use stand offs (Deck2Wall spacers for airspace) to hang the deck ledger.

 

[Inspector Gift]

All of these flashing details assume the structure has sheathing behind the siding or stucco. What do you do when you have a structure with wire backed plaster (or wood siding attached directly to studs) and no sheathing (typical 1950's post war homes)? Seems too invasive to open up a large chunk of wall instead of just lagging into the rim joist and use stand offs (Deck2Wall spacers for airspace) to hang the deck ledger.

Short Answer: Locate the framing members. Fasten to the structural members. Flash or space ledger away from wall to allow water to pass behind the ledger without penetrating the wall membrane.

Best Answer: Upgrade the exterior wall sheathing and cladding and Flash according to FEMA Technical Fact Sheet No. 23.

 

[steveray]

Making the writing bigger is not going to solve the problem.....Not that I wouldn't support that code change......But.....