Flashing Deck Ledgers 2021 UPDATE

hello and welcome to building codes for building decks ledgers and lateral loads this session is all about flashing but before we talk about flashing we've got to talk about cladding and removing it now it hasn't always been this way these are photo examples of many many decks i built on new homes in the 90s all of them passed inspection and all of them were built over the top of the cladding and connected right through whether stucco or siding now this is a familiar photo to many deck builders but it's a different kind of past now this is in the past it's not okay anymore and never really was in the first place but you don't have to believe me let's go to the ledger connection table for the structural provisions of this connection and notice there's a maximum allowable sheathing thickness in each column and different sheathings that are permitted but these details are going to come in a session later now if this code is this particular about the shielding between the band joist and the ledger connecting it to it it's pretty easy to understand why the cladding is going to definitely have to be removed for that connection but there's something else to talk about even before we get to the flashing because after you remove the cladding there's a good chance you will find a water resistive barrier and it may be asphalt paper or it could be a proprietary product like this there also might be none because this has not always been universally required behind all claddings the water-resistant barrier is terminated and flashed at penetrations like dryer vents or combustion air inlets and at windows like you see here but what about where ledgers attach to walls well if we look at section r 703.2 we find that the water resistive barrier must be terminated at penetrations and building appendages which that pretty well speaks to decks so after the cladding is removed next comes the barrier or not you don't have to remove it you just have to terminate it so consider what's done with porch roof additions to protect the home during construction the shingles are analogous to the cladding and they must be removed for the structural connection of the roof over the other roof but the underlayment can be left there for protection when the shingles are installed later the underlayment can be properly installed into the new valley and this is in the same way that the water resistive barrier over a deck can be later terminated when the flashing is installed now going back to that page in the code we just looked at we find this part that requires the water resistive barrier termination to also direct the water out from behind the exterior cladding and that brings us to flashing because that's exactly what it does now since this is about dex let's start with the deck section now this section here is only going to be about the flashing materials and the first requirement is that it be corrosion resistant metal while that might seem easy to understand the irc has provided a definition for corrosion resistance and it's pretty obvious but it does speak to the environment that the flashing is in so depending on the environment galvanized steel could work but if you've got a lot of salt spray from a house on the coastline you may want stainless steel or aluminum and take a quick note here of the barrier between the aluminum and the copper treated lumber here's an example where they used copper flashing wow copper but if we go back to this section again and we read further we see that the flashing has to be compatible with the structure and the decking basically the materials it's c in contact with so copper may have been selected in that photo due to the high copper content in the treated material may also be the reason we saw the barrier between the aluminum and the treated material now we also see that non-metallic material is permitted but it must be approved and we learned in the first course of the building codes for building deck series that approved means it's acceptable to the building official so would they approve a plastic or vinyl flashing material well why not now all we've done so far is talk about the material we've got to also go to the footnotes in the ledger connection table to find out more about flashing this footnote points us over to section r 703.4 for more details and it also tells us a little about the purpose which is the flashing should prevent water from contacting the house band joist oh boy more code sections now we're going to put this one up on the chalkboard and talk about it step by step but first i want to take note of where flashing is required here it says where decks or stairs attach to wood frame construction let's look at these newly rebuilt stairs notice the deterioration of the siding where the old stairs were up against the house well if we look underneath we see that the builder attached stairs to wood frame construction and though i applaud the desire of the builder perhaps to brace these stairs laterally well maybe not maybe it was the lack of the connection here at the top of this stringer but neither either way i tend to recommend for bracing stairs laterally to brace them within themselves and that way they can be held off the house a little bit because otherwise if they are connected to the house there's going to be some flashing that's necessary and if they're not connected brace them independently and perhaps a little gap so you can allow the debris and water to flow through and not damage the cladding now here's a similar example notice the damage sighting from the previous deck connection but look at where the new ledger is it's attached to concrete construction not a wood frame assembly and thus no flashing is required see the flashing isn't really there just to protect the ledger we'll learn later that that has to be decay resistant material i mean if we had a powder coated steel ledger that's pretty decay and corrosion resistant we'd still flash the ledger many deck builders know this well as they have faced major repairs to a house after tearing out a deck that didn't have flashing all right let's go back here and now let's put this code section on the chalkboard and break it down a bit right from the get go we see that all flashing has to be approved corrosion resistant not just the metallic now the only directions provided for installation of flashing is that it must be done shingle fashion now i know what you're all thinking when i say shingle fashion because it's confused so many people that it was some wacky european fashion show that we actually have a definition now in chapter two to keep us straight okay here it is but i'm not going to read it to you so i want to show it to you here's a roof and when we install shingles they're placed at the bottom and we overlap them working their way up all the way as we go to the roof shingle fashion right now when the rain falls on top the lapping sheds this water to over and over and over to the next course and no sealants for water resistance are even used now let's replace this roof with like box shaped appendages right and use flashing shingle fashion like the shingles we would install flashing from the bottom with each course overlapping the one that's below and when our water drops it sheds all the way down which way shingle fashion i know these are worse than dad jokes but when you find a guy making artistic dresses from shingles online hey what can you do all right back to the code we see we have another statement in here about the purpose for flashing and this is coming from chapter seven saying to stop the entry of water into the wall cavity but we already got a similar message to this from that footnote we read in chapter 5 in the table chapter 7 does provide some more information about non-metallic flashing like that self-adhered products must comply with the aama-711 standard it's a test standard for material now the last thing i want to mention about the chapter 7 flashing provisions is this part here that will bring us back full circle to the water resistive barrier it says that the flashing shall extend to the surface of the exterior wall finish so as this example reveals the face of the ledger really is the surface of the exterior wall finish and so back to where we started this is what would drain water shingle fashion from the resistive water resistive barrier to the flashing and to the exterior my name is glenn mathewson thanks for learning with me this video was provided to you by buildingcodecollege.com where we go beyond the words

Channel: Glenn Mathewson

Views: 278

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Id: 4OpT-MokKg0

Length: 9min 53sec (593 seconds)

Published: Tue Jul 13 2021