Optimum Bones: An Engineer's Take on the Best "Bones" for Your New Home
A fairly frequent question for a prospective homeowner, or an advising
agent, is about the “bones” of a home. When
someone talks about the “bones” of a house, they are usually focused
on primary components of the house (and likely not the cosmetic finish
choices). Think of it as a good home that has the potential to be great.
I started thinking about this when I wrote the article “Good Bones” of a
Structure (Engineering Perspective). This follow-up article is intended to explain
what “bones” I would pick for my New Home Construction in Florida
(while most can hold true in your state, a review of the local weather perils
should be carried out).
Table of Contents
Having spent 20+ years inspecting failed structures, I have seen quite a bit that works (and works extremely well) and what clearly doesn’t work. The state of Florida is unique in many ways. The climate is great for outdoor sports, and is a phenomenal place to retire. The seasonal visits from hurricanes, however, as well as the frequency of Floridians in the news, are some of the things that make this state….unique.
Winner: Monolithic footer, and slab on grade.
This element is typically stronger and more durable than other foundation elements (like wood-frame construction). It also requires less in-depth knowledge to adequately construct, and less labor dependent. These can be constructed much quicker than other common elements, and are typically cheaper. Site conditions, however, may not be suitable to construct this type of element. An irregular sloped site will not work with these foundations, or in areas with higher groundwater levels. Also, areas expecting larger rainwater events should probably consider a continuous strip footer with a raised slab-on-grade. This foundation does not give its owner a termite/insect concern (itself), and is clearly more suited in moist and humid areas. These are more energy efficient than wood framing and comparable to continuous strip footers. This flooring system can accept nearly all major finished flooring options, and is particularly superior for any type of tile installation. Lastly, this flooring system, once adequately constructed, provides a maintenance free foundation for the home.
Winner: Concrete Masonry Unit (CMU) walls
These walls are superior than other major wall systems, like wood and metal in terms of strength and fire resistance. CMU provide solid water resistance (themselves) and can receive most any of the common exterior cladding materials. Stucco installation, in particular, is most strongly suited for CMU construction because the coefficient of thermal expansion is nearly identical since both are cementitious materials. This means they tend to expand/contract at the same rates (again remember, differential tends to be bad in terms of building/material movement). The wall (itself) is inorganic and will not promote or harbor mold growth. It provides termite resistance since the insects cannot consume or degrade it, and it provides superior sound proofing.
Winner: Engineered truss
This option is superior over
conventional framing in terms of convenience, and can accomplish enlarged spans. These get you assured structural capacity, as
they are designed for certain capacity.
You also get quicker assembly, and here you are less reliant on labor
Winner: Hip over gable
This selection was mainly for wind resistance and aesthetics. Here in Florida you get some solid insurance discounts as well. Whatever you choose, ensure your expert evaluates the FUNCTION of the roof more so than the aesthetics. I can easily say that the vast majority of failures that I see are related to poor flashing, and the complex roof geometries out there cause some of the most difficult to design.
Winner: TIE between copper and CPVC
Both, once installed properly, last a very long time with no maintenance. CPVC is a little easier to install, and copper much more expensive. Pex is a great product, but seems best for remodels or retrofitting (admittedly I have limited experience with Pex).
Winner: PVC for the drainage system
The Drain, Waste, Vent (DWV) system should be PVC. Other types of piping degrade over time or are brittle/prone to root intrusion or breakage. Such pipes are: Clay, Steel, Cast Iron, Orangeburg (made from wood fibers with adhesives). Acrylonitrile Butadiene Styrene (ABS) is similar to PVC, and suitable for this application but uses a differing chemical. ABS may be preferred in very cold/freezing climates. You typically will not see newly constructed homes with anything other than PVC or ABS.
Winner: TIE vinyl flooring and porcelain tile
Obviously, the choice for finished flooring is a very personal one. This material was selected almost solely on his longevity, ease of use and resistance to deterioration (again, remember I’m an engineer). So the correct flooring for the correct area will have to start with your intended use (i.e. you wouldn’t put carpet in the bathroom; although people used to).
Vinyl flooring is extremely water-resistant and does not damage by water exposure (it can sit in water for extended periods of time). It’s primarily made of plastics and is available in tiles, sheets and planks. Vinyl Composite Tile (VCT) and Luxury Vinyl Tile (LVT) are options that have gained popularity lately, do to their extreme durability and the styles available that work with many installation scenarios.
Porcelain tile are great because they are very resistant to moisture absorption. Your toilet, in contact with water at all times, is likely porcelain. I know we mentioned thermal expansion and contraction a few times, but moisture absorption and release do the same thing. These tiles are not overly affected by that. Ceramic tiles, on the other hand, absorb moisture and expand with heating so the linear changes may be enough to cause it to delaminate from the substrate and/or crack. These tiles are also significantly more dense than ceramic tiles. While this will likely wear out more saw blades, it’s not such a bad thing for longevity and use in commercial/high traffic environments. A dropped tool or dish can ruin an entire room worth of ceramic tile (as you usually cannot find replacements and the interior/body of the tile is usually clay-red color), but porcelain tile are the same color throughout it’s body. So a chipped tile looks closer to the color of the tile itself, giving it a fighting chance to blend in without being overly observable. They are also less susceptible to stains to the decrease in porosity. There is a reason that very few ceramic tile options tend to be available, as people tend to favor porcelain. Expect to pay more for these tiles, as they are made with more refined materials and fired longer to create that impermeability. Don’t be afraid, however, to use those beautiful ceramic tiles in non-wet or areas where you feel these movements will be problematic.
Also, in either case, the integrity of the substrate is the real critical factor for the performance of your chosen flooring material. Any tile that you install atop a wood-framed floor may crack, if provisions to stiffen the floor or if the framing elements are not conducive to elimination of floor movement.
|Foundation||Monolithic Footer (site/elevation permitting)|
|Walls||Concrete Masonry Units (CMU)|
|Roof Framing||Engineered Truss|
|Plumbing (supply)||TIE, Copper & CPVC|
|Finished Flooring||TIE, Vinyl Flooring and Porcelain Tile|