SImpson Strongtie now has a DTT1Z tension connector which does not require invasive attachment inside the house. It connects the joists to the house sill plate. Lag screws attaching a ledger to the house band joist are fine for resisting lateral load, but they don't solve the problem of joists pulling out of their nailed hangers which have low pull out resistance.
My home was a kit home constructed of manufactured glulam logs and tji joists. The deck was attached to the parallel rim joist which was simply a tji joist with a plywood web stiffener added on the exterior side and squash blocks on 2' centers behind it. It was constructed in the mid 1990's by the home owner who wasn't a professional. There was no flashing and the ledger was fastened with a couple of 16 d nails on each end and a few short nails through the web of the joist. The rim joist web water damage under a patio door was significant. I replaced the rim joist with lvl backing it up with squash blocks 1' on center and lvl blocking behind the original . I flashed behind the ledger and reattached with Ledgerloks per code. I flashed on top of the ledger with self adherent material and galvanized steel flashing. I added 4 Simson DTT1Z lateral tensioners into the sill. Perhaps not needed, but I see it as insurance.
No matter how well a code can be written, there will always be those with poor reading comprehension skills. Thanks Glenn for trying to do something about this!
Nice video, This presumes other things do not fail at connection points and deck design detail. The lateral tensioners when connected to the joist at each sideof the deck helps prevent the disconnection of the joists to the rim joist secured to the home. This video appears to be politically generated as well as informative. If loads are applied on the ends of the deck to creat a force pulling away from the home lateral tensioners applied properly would keep the banding joist tight against the home and prevent a collapse where the deck meets the structure. To remove tensioners from the code would be a mistake without proper provisions on deck joist direction and proper banding joist installation. In 22 years of inspections i have yet to see a deck properly constructed in the south central texas region!!! I think one must consider over engineering of decks through the code due to the bob villa syndrome of home owner and handy man constructed decks.
The plan of the IRC is the plan of those that contribute. I think the only way to properly address lateral load analysis and design in decks is through more research, knowledge and contribution to the I-code development process.
Proper flashing at the ledger may not seem important on a new deck, but over the years water getting behind it and not being able to dry out may lead to rot or spongy wood that the lag bolts are attached to. If the framing nails used to attach the band joist to the floor joists rust out, the deck could easily pull away from the building and collapse. I’ve read that putting spacers or galvanized washers behind the ledger to create a space for air circulation is an option, but I wouldn’t do it.
Glenn, I really enjoyed this article. How does this relate to joist pull out away from the home? I never really considered it an issue for side to side but, have seen decks where all the joist pulled out of hangers. I tend to think several hurricane clips from ledger to joist would be more effective than two or four really big connections like these in your video.
When they propose stuff like this they should have to build a model and show it actually working. Yet, I see inspectors in my county and neighboring county not give two shits about flashing on the ledger which starts this issue in the first place. This includes my deck that was inspected but not flashed at all and had areas that trapped water. This is what happens when people who work in a lab have no idea of real world application.
SImpson Strongtie now has a DTT1Z tension connector which does not require invasive attachment inside the house. It connects the joists to the house sill plate.
Lag screws attaching a ledger to the house band joist are fine for resisting lateral load, but they don't solve the problem of joists pulling out of their nailed hangers which have low pull out resistance.
My home was a kit home constructed of manufactured glulam logs and tji joists. The deck was attached to the parallel rim joist which was simply a tji joist with a plywood web stiffener added on the exterior side and squash blocks on 2' centers behind it. It was constructed in the mid 1990's by the home owner who wasn't a professional. There was no flashing and the ledger was fastened with a couple of 16 d nails on each end and a few short nails through the web of the joist. The rim joist web water damage under a patio door was significant. I replaced the rim joist with lvl backing it up with squash blocks 1' on center and lvl blocking behind the original . I flashed behind the ledger and reattached with Ledgerloks per code. I flashed on top of the ledger with self adherent material and galvanized steel flashing. I added 4 Simson DTT1Z lateral tensioners into the sill. Perhaps not needed, but I see it as insurance.
A must for anyone constructing a raised level deck. I would like to see a proposal for a block and brick construction.
Many thanks
Karl
No matter how well a code can be written, there will always be those with poor reading comprehension skills. Thanks Glenn for trying to do something about this!
Great video with a wealth of knowledge thank you for this!
Nice video, This presumes other things do not fail at connection points and deck design detail. The lateral tensioners when connected to the joist at each sideof the deck helps prevent the disconnection of the joists to the rim joist secured to the home. This video appears to be politically generated as well as informative. If loads are applied on the ends of the deck to creat a force pulling away from the home lateral tensioners applied properly would keep the banding joist tight against the home and prevent a collapse where the deck meets the structure. To remove tensioners from the code would be a mistake without proper provisions on deck joist direction and proper banding joist installation. In 22 years of inspections i have yet to see a deck properly constructed in the south central texas region!!! I think one must consider over engineering of decks through the code due to the bob villa syndrome of home owner and handy man constructed decks.
Answered my question. Thank you!
Seven years passed. Does IRC have any plan to get rid of this lateral tension device requirement?
The plan of the IRC is the plan of those that contribute. I think the only way to properly address lateral load analysis and design in decks is through more research, knowledge and contribution to the I-code development process.
Very informative. Very well done!
In the last test (WDF summer 2013), how was the band joist attached in the "mocked up floor assembly"?
Proper flashing at the ledger may not seem important on a new deck, but over the years water getting behind it and not being able to dry out may lead to rot or spongy wood that the lag bolts are attached to. If the framing nails used to attach the band joist to the floor joists rust out, the deck could easily pull away from the building and collapse. I’ve read that putting spacers or galvanized washers behind the ledger to create a space for air circulation is an option, but I wouldn’t do it.
Flashing has been required for many years now. Your point is moot.
it only doesn't seem importatnt, to hacks.
Glenn, I really enjoyed this article. How does this relate to joist pull out away from the home? I never really considered it an issue for side to side but, have seen decks where all the joist pulled out of hangers. I tend to think several hurricane clips from ledger to joist would be more effective than two or four really big connections like these in your video.
When they propose stuff like this they should have to build a model and show it actually working. Yet, I see inspectors in my county and neighboring county not give two shits about flashing on the ledger which starts this issue in the first place. This includes my deck that was inspected but not flashed at all and had areas that trapped water. This is what happens when people who work in a lab have no idea of real world application.
Would be nice to remove that requirement from the the code, it never made any sense.
A though bolted ledger isnt going anywhere without taking the whole house with it ! This is a ridiculous code and needs to go