Deck Failures

My biggest fear in Home Inspection is missing a bad deck.
I find most decks are not built properly and I look hard and make sure I miss nothing .
We had one in Canada let go a few years ago with a lot of very important people on it and there was many seriously hurt.

Michael Leavitt has started a new web site on decks have look you will learn a lot .
Information on the deck that fell today in Virginia is on it already .
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thanks for the link good stuff

Here is a site with info on how to build one correctly etc…

Many “deckaroos” are cutting corners by nailing the header to the home exterior instead of bolting it. :mad:

Here’s one from yesterday, brand new 3800 square foot home, never lived in and both the front and rear deck were not bolted to the outside rim joist, not to mention they left the OSB sheathing under both decks exposed.

With wrong size hangers to boot. ha. ha.

Nice pick up Peter.
Looks like a crack in the foundation too. Hope the water proofing is below grade and adequate.

Marcel :slight_smile: :wink:

Nice sites guys…

Here’s a deck that I found which had NO LEDGER BOARD whatsoever. It was attached to the lower 1/2 inch wood trim below the siding.

Nice connection ayyy?

“click to enlarge”

I had an inspection a couple days ago where only lags were used in areas I thought through-bolts should have. Areas of wood were separating with age, and needed tightening. I felt bad for ‘flagging’ concerns about a year old deck. :frowning:


Another good article by Dek-Lok.

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DeckLok in the Press

Back to the main In The Press Page
Responding to Deck Failures

Dec 2006 DeckWorld Magazine
A deck failure can be as simple as a board that gives way or a sag that develops at one corner. It can also be as dramatic as the whole structure pulling off the second story of a house.

You’ve seen the headlines and heard the news reports:A deck on a house in the 800 block of South Elm collapsed in the midst of a 30th anniversary party Sunday afternoon, sending five guests to the hospital with various injuries, none serious.

The good news, of course, is that no one was seriously hurt. Unfortunately, that’s not always the case. Of the deck collapses that were reported in 2006, 94% resulted in personal injuries. The actual number of deck failures is very difficult to know. Many deck failures go unreported because emergency crews were not summoned or the deck was not occupied at the time it went down. Additionally, decks that were clearly unsafe and were repaired or replaced before they collapsed are not recorded either.

*DeckWorld *talked at length with Michael Morse, founder and president of DeckLok. Morse has been studying deck construction, building codes, and ways of developing a failure‑proof system for almost 25 years.

Morse points to studies that show over 90% of deck failures are linked to a failure in the connection between the house foundation and the deck. Metal fasteners (whether they are bolts or nails) embedded in wood depend on the resistance of the wood fibers to hold the screw or nail in place, attaching the deck ledger to the house. But this assumes that both the fasteners and the surface they are gripping have the appropriate construction integrity.

For starters, these same metal fasteners offer a pathway for water and then rot in the wood they are supposed to be holding. Seasons of freezing, thawing, and heat cause wood to dry, split, or even rot. Screws may loosen or pop out. Nails provide a much weaker connection to begin with and are more susceptible to popping. As Morse points out, it only takes a slight shift in the surface to begin a lateral pull on nails or screws. For example he points to how easy it is to remove a nail from a piece of wood, once it has started to withdraw. The lesson here, he says, is that once fasteners start to pull out, it does not take much for them to pop the rest of the way.

What about the building code?
According to the International Code Council (ICC), for the most part, “there are no prescriptives for decks in the International Residential Code. They would be treated as floor construction and would follow Chapter 5 of the IRC especially the floor joist spans table.”

Specifically, the 2006 International Residential Code, R502.2.2 Decks, stipulates: “Where supported by attachment to an exterior wall, decks shall be positively anchored to the primary structure and de­signed for both vertical and lateral loads as applicable.” It goes on to describe attachment methods and structural supports.

At its recent 2006 hearings in Orlando, the International Code Council Code Committee adopted a prescriptive method for attaching the deck ledger to the house, but it does not specify which part of the house this is. It even specifies the number and placement of bolts.

Morse points out, however, that most decks are inspected the day they are complete - when the materials are new and they have not been subject to weather or weight. The damage comes when this same structure has been left in the elements - wet, cold, snow, heat‑for a decade or two.

By Morse’s definition, a successful deck is one that remains structurally sound throughout the service life of its wood. Engineering for decks, he says, needs to account for the fact that wood changes over time.
Morse believes there are three key facts to keep in mind in preventing deck collapse:

  1. Follow the load path to the footings. According to the International Code Council’s Residential Building Code, the “design must be capable of transfer­ring all loads from their point of origin to the foundation.”
  2. Do not assume you have created a structural link if you have not seen the structure. Often‑through no fault of the homeowner or builder‑the deck is not tied to a structural member of the house. The band joist must be specifi­cally attached to resist being pulled out by the deck. The deck ledger may be fastened with the correct number of ap­propriately sized lag bolts, but they may only be holding on to siding or an un­supported band joist. There must be a structural link to the house foundation.
  3. New construction methods that use materials such as manufactured “I” joists do not necessarily tie structurally into the band joist. In this case, a deck can collapse and take the band joist with it.
    What about vinyl and composite materials? Vinyl and composite decking materials attach to the same deck underpinnings as wood decking does, but with some differences. The hidden fastener systems these materials use hold decking in one direction, making the stability of the substructure that much more important. Morse says any structure needs to accommodate the characteristics of the new product.

There are no bad guys here. Morse is quick to praise the craftsmanship of deck builders. In fact, he says, most of them do a beautiful job - for 95% of the deck. He believes the last 5% - fastening the deck to the house - is where there’s room for improvement.

**The following specifications regarding decks is from the 2006 International Residential Code:**Section R501.2 Requirements

Floor construction shall be capable of accommodating all loads according to R301 and of transmitting the resulting loads to the supporting structural elements.**R502.2.2 Decks.**Where supported by attachment to an ex­terior wall, decks shall be positively anchored to the primary structure and designed for both vertical and lateral loads as applicable.

Such attachment shall not be accomplished by the use of toenails or nails subject to withdrawal. Where positive connection to the primary building structure cannot be verified during inspection, decks shall be selfsupporting. For decks with cantilevered framing members, connections to exterior walls or other framing members, shall be designed and constructed to resist uplift resulting from the full live load specified in Table R301.5 acting on the cantilevered portion of the deck.Table R301.5states that decks must be able to support 40 pounds per square foot. Exterior balconies must support 60lbs per square foot.

To learn more, please contact the Intema­tional Code Council,

© DeckWorld Magazine

Marcel :slight_smile:

Good call Marcel, I left that one hanging ( no pun intended ) to see if anyone would catch it. There were many other problems with this house, I’m sure the builder wont be to happy!

We have to call it the way we see it don’t we? Nothing wrong with that.

Good job Peter, and hope you are keeping busy.
Stay in touch.

Marcel :slight_smile:

80% of decks I see are not built correctly .
Please be carefull do not miss writing them up another deck collapsed last night two in hospital .

Another Collapse Two people were taken to the hospital after a deck in Brooklyn Park collapsed. 20-30 people were standing on a deck of a home Saturday night, when it fell out from under them. Two people were taken to the hospital for their injuries. Hospital officials have not yet revealed the condition of the two people who were injured. Police have not yet determined the cause of the collapse.
The coverage from WCCO and Kare11 was very brief and fact based. The police was only source used in either story. Using the police as a source is intelligent because they do research similar to that of a reporter so the information is pretty reliable, but I would have loved to hear from one of the victims. The sources were authority figures.

… Cookie

Check out the size of the screws (not bolts) securing this deck ledger to the house. How 'bout the mini joist hanger. I also called for an evaluation of the 4x4 posts without bracing.

100407 042 (Small).jpg 100407 012 (Small).jpg 100407 046 (Small).jpg

100407 042 (Small).jpg

100407 042 (Small).jpg


Are those tapcons?


Good call Marcel.
I asked the same question when I saw the 1st pic. If you look in the upper left corner you can see what appears to be concrete, so I beleive they are (plus being blue as tapcons are).

My real concern, as Joe pointed out in the 3rd pic using too small of a hanger, but also using regaular common nails to attach the hanger and the gap in the ledger board (3rd pic) that the joist is so nicely covering up. That must be a weep hole for the deck!:mrgreen: Also the flashing goes behind the ledger and not over the top of the joist to direct the water away from the house.


I agree with you. I don’t like using 4x4’s for support post. Whenever I have a deck built, I insist on using 6x6’s. I’ve had local building ordinances stipulate the use of 6x6 post on anything over 7’ off grade. To me 6x6’s look beefier and it allows me to notch them to insert a double 2x beam and bolt the beam to the post.


10-4. Tapcon secured to wood. The material you see above is flashing, not concrete. The nails used on the joist hangers looked like roofing nails to me, but I’ll let the contractor address that. I also called out the improper flashing, as portions of the band sill inside the crawl were rotted.

I questioned how the house ever got a CO (lots of code violations on a 11 year old home) and recommended that the buyer confirm the issuance of proper permits (the homeowner was a builder and the house was way back in the sticks).

I didn’t even notice the gap until you pointed it out. Nice.

And that wire was lucky. ha. ha.

Nice job. Keep it up.

Marcel :slight_smile:

Joe, I taught a class on deck construction and the proper attachment to our NH chapter and just realised that I should have created a deck check list as part of it.

You can easily miss something and then see it in a photo after.

Something to work on and post.

Are tapcons on your list of proper deck construction methods?