Permissible, now there is a word subject to wide interpretation. Look at history or around the world or even on your own street. There is no question what one person finds permissible, another sees as offensive. For literally thousands of years, the way to take a good deal of the subjective-ness out of things is to make rules.
In the world of residential construction these rules are known as building codes. Building codes themselves date back thousands of years. The Greeks and Romans created and used building codes. Archaeological records of a building being constructed by the Greek philosopher Socrates in part state:
"He shall set the joints against each other, fitting, and before inserting the dowels he shall show the architect all the stones to be fitting, and shall set them true and sound and dowel them with iron dowels, two dowels to each stone…"
This I think demonstrates that it has long been understood when a building or structure is constructed, it must have a uniform method. It also must be strong and above all else, safe. It also shows incompetence and shoddy work are just as old as civilization or there would be less of a need for codes. Yet codes are only half the process. While they do exist, it does not necessarily mean they are followed by all. Another thing that hasn't changed with civilization's history. Thus the need for over site.
The process used today in many parts of this country, not all, but many, is the permitting and inspection of construction. Basically permits are taken out with the local building department. Then at some point the new construction is inspected by the local building official. When the project meets his or her approval, the permit is closed.
Let me repeat, the permit is closed.
As a home inspector I am inform often that permits were pulled for _____. My response is always the same, "are they closed?" This can at times receive a quizzical look on the face of the one who made the statement.
Recently I inspected a permitted deck. I really have come to despise decks. There is almost always something wrong.
The first glaring defect was the ladder like guard rails and lack of handrails. Stooping to look under the deck at the support structure, I was dumbfounded by what I saw. The main support beam was very noticeably bowing. The reason was very clear, this beam by my estimate is well over 20 feet in length and devoid of an center support. A 4 x 4 post was stationed at each end, nothing any where in between. But wait, it gets better.
Going around to one post of interest, I saw the pier was not squarely on the footing. Looking at the attachment to the beam, I saw four nails. Same on the back side. The support beam was actually two separate boards face nailed to the two posts. The center of this large deck in essence is supported solely on a total of 16 nails.
The best method for constructing a pier beam support is to set the beam on top of the posts. In this way the load is distributed evenly along the beam, with the piers fully supporting the beam, not a set of fasteners.
There were several other issues with this permitted deck, which goes to show, permissible is open to interpretation, especially when circumventing the rules.