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The Critical Eye!

Michael Leavitt’s professional inspection related blog.

Deck Ledger Connections - Simpson SSD’s

Deck Ledger Connections - Simpson SSD’s


As a home inspector I have become quite aware of deck failures over the years and look at their inspection as a high priority when they are attached to the homes I inspect. The International Residential Code seems to be very clear that the attaching point to the home requires 1/2” bolts or lag bolts with washers. Anything less is supposed to be unacceptable, this includes the use of just nails only. This is to help prevent injuries and death from collapse.Simpson SSD

On the surface this seems like a very simple item to look for. About 2.5 years ago I started to see a new kind of bolt that was smaller and was being used with no washer at alland I started running around like Chicken Little until my phone call to the engineers at the manufacturer was returned and I gained some great peace of mind. It turns out that the long time standard 1/2” lag bolts or bolts with washers is the main method of attachment, BUT the IRC allows for alternative methods of attachment as long as they are engineered. The IRC states,

R502.2.2.2 Alternate deck ledger connections. Deck ledger connections not conforming to Table R502.2.2.1 shall be designed in accordance with accepted engineering practice. Girders supporting deck joists shall not be supported on deck ledgers or band joists. Deck ledgers shall not be supported on stone or masonry veneer.”

Sure enough, Simpson Strong Tie came up with an easier way to install an approved fastener. It is smaller in diameter, it is self-boring, and it requires no washer. Was I skeptical? You betcha! Two months later I found myself sitting in an all day Simpson Strong Tie seminar that showed off all the newest products. The engineers were present and I interviewed them in-depth on the new SSD’s. They answered each question and showed all of the needed documentation to back up their statements.The room was filled with over 50 municipal inspectors, architects, structural engineers and myself and a fellow home inspector. They convinced me and the entire room of building professionals as to their adequacy.

SO HOW CAN YOU IDENTIFY THEM? That was my big question to the engineers. They showed me the head and the identification marks. If you see these markings, then you should rest assured that it is an approved fastener. If you don’t see it, then you best start asking questions...

Simpson SSD 5

I know that you still have lots of questions and these are best answered by the information sheet from Simpson Strong Tie. They provide the references needed to research the issue further yourself. I am all about pointing others in the right direction and encourage them to go research, just like I had to do. So here is the SimpsonSSD.pdf...

Simpson SSD 2

NOTE: You will see in the PDF DOWNLOAD that there is an expiration of 12/31/2012 (NEWER VERSION). Please keep in mind that the IRC references are 2009. IRC 2012 references are moved to R507 from the older R502. So depending on which version of the IRC you are using you need to know where to find the “Code Equivalent Deck To Ledger Connection” information. Also visit my website, especially the article forwarded on to me by Professor Emeritus Frank Woeste, from Virginia Tech University regarding the big 2007 code changes in deck attachment requirements...

As always, I am hoping that this information is helpful...


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