Fact or Opinion

I find as a home inspector people look to me to provide them with information on the condition of the house they are in the process of purchasing. By its very nature a home inspection is based on both facts and opinion. During a home inspection, and after when writing the report, the inspector will attempt to provide opinions, when a judgment is needed, that will, should be based on available facts.

The difference between fact and opinion can be said this way;

In general, an opinion is a judgment, viewpoint, or statement about matters commonly considered to be subjective, i.e. based on that which is less than absolutely certain, and is the result of emotion or interpretation of facts. What distinguishes fact from opinion is that facts are verifiable, i.e. can be objectively proven to have occurred.

I think it is safe to say, fact and opinion are unmistakably different, yet can in certain instances be confused and or convoluted.

One of the most common additions to many homes is a wooden deck. They are also more often than not, incorrectly constructed. It is extremely rare for me to find a deck that does not have at least one deficiency.

Some are real nightmares.

Modern deck building standards are not based on opinions so much as on known and tested data. Like so many changes in the construction of houses and buildings, the standards have evolved too often from catastrophic failures. Injuries and loss of life often the impetus.

A strong and safe deck is not a particularly complex structure. Typically there are two main structural points on the deck. The ledger board and the beam(s), posts and footing. This animation by Simpson Strong Tie depicts the continuous load path of a deck structure. The remainder of the deck is built upon this basic structure. The joists that the decking is eventually attached and the stairs and guard rails. In case one were to think, and based on my experience people do, that the remainder is not as important, that would be a wrong assumption.

Going back to the company that gave us the load path animation, Simpson Strong Tie, if one were to peruse the site further, you would find many other components for building a strong and safe deck. The most common being the joist hanger.

Joist hangers are used to securely attach the structural members to the deck structure. Looking at the diagram, one can see there are holes where the fasteners are to be driven. The smaller, circular image is meant to show the proper penetration  of the fasteners. Logically this should be interpreted to mean that not just any fastener will do, because it won't.

On a recent inspection of a newer deck that also has been attached to and older deck, I found all the hangers and structural hardware to be fastened using screws. Deck screws. Yes it is a deck, but deck screws are meant for fastening decking to joists and balusters to guardrail members. Deck screws are not strong. They are not structurally rated. They are made from old beer cans and Volkswagens. No, not really, but you get the idea.

Further, the deck had been built using an unconventional framing method. Instead of attaching the joists perpendicular to a ledger board securely bolted to the house structure, this deck builder opted to use several beams attached to a board secured to the house structure. The method turns the typical structure 90 degrees and introduces a host of structural hurdles.

The newer deck has a total of three beams. One would, could have been used. The outer portion of each beam is supported by a post which has been secured to the beam with a plate with a lot of those deck screws. A specific piece of hardware is available for the purpose of fastening the post and beam, but it costs a lot more than that plate.

That happens to be the best part of the post and beam structure. Two posts are set upon a concrete block wall and the third, I'm really not sure. My 12" screw driver is pushed into the ground up to the hilt next to that post. There can not be a footing below that post.

The other end of the beam is supported by a large joist hanger screwed to the ledger board. For added strength an L bracket was added. The bolts used in the bracket are of adequate size, but that bracket offers little added strength.

Here are the facts, joist hangers or any hardware can not be fastened using deck screws. First and most important, any fastener not specified by the manufacturer means the component will not perform as intended, i. e., it will be weaker structurally.

Simpson specifies nails or structural screws (made by Simpson) for their hangers. Each and every piece of hardware is engineered and tested. The deck structure is weaker than could be expected if the proper fasteners were used. Further it is also weak due to the other inadequate structural elements incorporated by the builder.

I was suspicious this deck had not been permitted and more importantly inspected by the city building official. Remarkably, it had been permitted...after it was built. Even more amazing the city inspector passed the structure.

My client, speaking with the building official due the concerns raised during the home inspection, showed the city inspector the inspection report. He said that in his opinion, the deck was structurally fine.

Fact or opinion, which would you trust?