Bathroom Flooring Options: Structural Support Issues Explained

Jan 18, 2012 by Frank Scherer

It’s something that the average person for the most part is pretty much unaware of. That is that there is an “engineered” structural support system built into each and every home. Now if you’ve ever seen a home that’s in the framing stage perhaps you can appreciate that in a way it really does look like the “bones of the building” because this is in fact what the framing members are. The “structural bones” of a home.

What you may be interested in learning though, is that somewhere inside the framing network of a home are the load bearing wall or walls and a “bearing wall” is a wall that’s designed and located in the structure to hold the “major weight” of a home. A pressure point if you will, where the greater majority of the weight of all that goes into a home will be directed, and this is why a bearing wall will always sit directly on the concrete foundation.

So then what does all this have to do with your bathroom flooring options? It turns out that it has a lot to do with them. That is unless the floor of your bathroom is concrete slab. If it’s it’s “not a wood floor” that’s built up on a raised foundation or on the second floor of your home.

The Building Engineering Plan Approval Process

You see, when your home was designed and the plans drawn up a “final approval” process was conducted by a county building engineer. In fact if you have a copy of the blueprints that were used when your home was built you can find the county engineers “approval stamp” right on the front page.

He or she went over your plans, took measurements, calculated the weight of the materials that were going into the building of it and then determined if the main structural support system was strong enough to support what the plans called for. For instance if they specified a tile roof which is of course much heavier than composition shingles, they checked the roof structure specifications and then determined if it was strong enough to support the “weight of tile”.

The engineer checked more than that too because just like the roof on a home the materials specified for in various bathroom flooring options can also vary in weight from one another. For example linoleum is obviously a whole lot lighter than ceramic tile, and the cement-board underlayment that goes down under it on a wood sub-floor.

The engineer checked where the bearing walls were located, measured the span as well as the dimensions of the floor joists, and the thickness of the plywood that was called for in the plans to be laid down on top of the floor joists. Then with that information in hand he or she was able to determine the amount of weight that the bathroom floor will support. Sam and Ann of apartmenttherapy.com went through this process when they designed and built their home.

A Floor Must Be Strong Enough For Tile Or Stone

So then does this mean that if you install ceramic tile on a bathroom floor that’s not engineered for the weight of a tile floor it will collapse? The answer here is a “simple no”. The floor will be perfectly safe to walk on. The problem you will have though, is that there will be a “slight spring” in it.

“Taking great care in working with architect Kevin Alter of Alterstudio, materials—like that gorgeous wood floor in the entryway from reclaimed barns or the soapstone kitchen counters—were chosen that infused the space with personality and function.”

A bounce that you won’t even notice when you walk on it. What you will notice though, is that in relative short order that slight bounce in the floor will lead to cracking in the grout along with tiles that will come loose.

So there’s a lot more to it than meets the eye when it comes to bathroom flooring options, and the last thing that you need is to learn expensive lessons the hard way when this all really is quite basic. That is that either your bathroom floor was designed and built to support light-weight flooring materials or it was designed and built to bear the load of heavy materials like ceramic tile or perhaps a natural split stone product like slate.

So then now the you’re aware of all this, it really comes down to one of two choices, with first one being to simply go with one of the lighter bathroom flooring options like linoleum or hardwood flooring because at the very minimum the “bones of your house” will support that.

Or if you’re exploring the concept of going with one of the heavier materials like tile or stone you need to make a determination as to whether the structural underpinning will support it.

How Strong Is Your Structural Underpinning?

Now if your bathroom floor already has ceramic tile on it, and it has “no cracking problems” then it’s a safe bet that the framing structure that’s supported it is strong enough. Or if your bathroom is on a concrete slab foundation, here again you’re free to go with pretty much any of the many bathroom flooring options available, including tile and stone.

However, if your bathroom sits on a raised joist sub-floor or it’s on the second floor of a two-story home, and it currently has a vinyl or hardwood floor a determination has to be made as to whether it will support a heavier flooring material before you do the job.

Now if you have a set of the blueprints that were used when the home was built you’re in luck because it’s a simple matter of taking them into a building engineer to have them examined. He or she will look them over, and then calculate what type of load your floor will hold.

On the other hand, if you don’t have a set of blueprints you’d be well advised to consult a building contractor. A professional who can come in, take the necessary measurements, determine what type of material was used in the structural underpinning, and sheeting then do a quick drawing that you can take to a building engineer.

Why Not Over-Build Floors To Support Future Upgrades?

So now you might be wondering “why they just don’t build homes that can accommodate all the bathroom flooring options that are available?” It would for sure make things a whole lot simpler and easier for owners down the road who are looking to upgrade. People who are looking to move up from, say vinyl to a nice custom tile floor in their bathroom.

What you need understand here, is that in all types of manufacturing decisions are made regarding materials and labor with the final selling cost in mind. Your house was built for a targeted price and all through the construction process, from design to completion, decisions were made every day to keep it within that targeted price range.

It’s not just the flooring either you see, because for instance when the roof structure was designed and engineered what type of roofing material was going to go on top of it was a major factor in deciding the cost of the materials and labor that was to go into framing it. Lumber is expensive, and the bigger and heavier the lumber is, the more expensive it gets. Labor costs also go up as lumber becomes bigger and framing systems become heavier, and more elaborate.

Then if you’re wondering why they simply couldn’t just design the flooring structure under the bathroom sturdier, and leave the rest of the home alone which would really have minimal cost impact there’s also an answer for that. That is that it’s more difficult than you may realize because the floor surface of the entire level has to match to be even. Using thicker, heavier lumber would have that area sitting up higher than the rest your floor.

The Bottom Line On Bathroom Flooring Options

In the end though, the bottom line here, is that if you have the money to spend you can upgrade any flooring system underneath a bathroom to accommodate even the heaviest materials. Now a structural upgrade project like this, if it’s required, will involve completely gutting the bathroom so it’s for sure not a simple weekend job. However, it can be done, and this means that all bathroom flooring options are open to you, if you’re willing to pay.