As I sit here with a bandage on my pinky toe, I realize my threshold of pain is the transition from my master bedroom to my master bath. That’s right the marble threshold between floor finishes. Why do we have those pesky thresholds also know as saddles? There are multiple reasons. They are a transition from one-floor finish to another, they protect your interior from the exterior elements, but the main reason you have one typically between the bathroom and adjacent room is that the tile in your bathroom needs a firm substrate to prevent cracking. To get that firm substrate a tile layer will install a mortar bed which is referred to as a thick-bed installation or thick-set installation. The mortar bed aids in leveling out the existing sub-floor. It reinforces the subfloor that could be subject to vibration, allows for radiant flooring if this is your chosen form of comfort as well as enables the floor to be sloped if for some reason you require a drain in your floor. So in creating this full bed, it raises up the floor from the adjacent floor finish creating the need for a transition. The tile could not just end without the threshold because not only does the threshold create the transition it protects the tile edge which is not as durable as the marble slab.
Sometimes you will see a tile layer install on a thin-set which is a more economical method of installing the tile, however, you will not benefit from the soundness of a full bed and possibly you will regret it later down the road when the tile cracks.
What else do we know about the threshold? Well, they have been using them for a long time! There is history of them going back to the time of King Solomon’s Temple, which is over 2,500 years ago! It was noted that the temple had thresholds 6 cubits wide. Go back to my blog “Do You Measure up” to discover how big that is.
Different cultures look at the doorsill in terms of symbolism. For example, the Chinese believe the sill creates a boundary between one’s property and the outside world. They also view the sill as a symbol of status. The higher your class the higher your sill height. I guess if you are physically challenged and rich you are going to have a tough time getting into your home. In the USA we have the Americans with Disabilities Act and New Jersey conforms to their own barrier free code. Of course, this does not apply to residential but the IRC does have a restriction regarding the threshold Section R311.3.1.
The threshold even inspires traditions and superstitions. We all know the groom carrying the bride over the threshold. I’ve read a couple of reasons for this, one is to bring good luck and keep away evil spirits and the other is actually the groom forcing the bride into the home to take her virginity giving the illusion that she is not too anxious. Russian and Polish cultures have similar superstitions of not greeting a visitor at the threshold and Romans always made sure to cross the threshold with their left foot.
So next time you walk through a doorway take notice of what is underfoot!