A home’s foundation is critical to its safety, longevity and durability. So before you build your dream house, understand which foundation options are best for your location and climate.
One option that is ideal for floodplains is a raised slab foundation. These foundations combine a poured slab with masonry walls elevated above the ground.
Monolithic Slab
A monolithic slab foundation is poured in one go, which makes it faster and easier than other concrete slab foundations. It is also stronger than traditional foundations, which expansive soil conditions can damage.
It is a good option for homes in mild climates, as it improves energy efficiency by reducing the amount of space that needs to be heated or cooled. However, it may not be suitable for flood zones.
This type of foundation can be built using plastic void forms or styrofoam, which is more environmentally friendly. It uses less concrete, which reduces labor costs and waste. A trench along the perimeter of the foundation creates a thickened edge.
Floating Slab
Floating slab foundations are poured concrete floors that sit on top of grade or underlying soil without anchoring. This foundation is usually used in sheds, manufacturing workshops, home additions and garages that don’t need a standard foundation.
Unlike traditional strip footings that use frost walls, floating slab foundations integrate footings into the concrete for faster installation and cost savings. They are also more environmentally friendly and work well across cold climates.
To build a floating slab foundation, level the ground and dig a trench around the site to prepare for construction. Fill the area with granular soil, leaving a 5-inch margin on both sides of the concrete forms.
One-Way Slab
A one-way slab is a slab that supports loads mainly in a single direction. The bending in this type of slab happens only along the shorter side, and it is designed with main reinforcement bars running parallel to the shorter span.
A slab foundation Killeen TX is considered a one-way slab when its ratio of longer span length Ly to shorter span length Lx is more than two. These kinds of slabs are commonly used in verandahs and chakras. On the other hand, two-way slabs support loads in both directions, and the main reinforcement is provided in both directions. Two-way slabs are suitable for smaller spans as they distribute loads more efficiently.
Two-Way Slab
Two-way slabs are designed to resist bending in both directions and can be used when the load is distributed more evenly. They are commonly constructed in buildings with smaller spans and lower loads.
One-way slabs are designed to support the load in one direction along its shorter span. The longer and shorter span ratio can be calculated as l/b > 2. The deflected shape of one-way slabs is cylindrical, while the deflected shape of two-way slabs is dish or saucer-like.
In this type of slab, the main reinforcement is provided parallel to the shorter side and distribution bars are supplied in the long span.
Stem Wall Slab
Many builders use slab-on-grade foundations. Climate, including high water tables and frost lines, and vulnerability to storm surges and harsh winters will often dictate whether or not a slab is appropriate.
Monolithic slabs are poured all in one go, which makes them quicker and cheaper to construct. They can be built in areas prone to flooding and offer a solid base for vertical walls constructed on the foundation.
Good construction practice demands that a moisture barrier be installed as part of the slab-on-grade system, along with sub-slab or slab surface insulation, to moderate the slab temperature and protect wood framing from moisture damage and termite intrusion. The slab-edge insulation should be a minimum of 8 inches from the perimeter of the foundation wall to isolate the concrete from heat transfer.
Pier and Beam Slab
Pier and beam slabs are primarily used for residential construction, but you can also find them in light commercial buildings. This foundation type is a great option for homes prone to flooding. Since the house is elevated, it’s less prone to flooding and moisture that can plague slab-on-grade foundations.
Another benefit is that the crawl space underneath a pier and beam foundation provides easier repair access. This makes repairing foundation damage or plumbing problems much easier and less expensive than a slab foundation. The piers and beams also help the house adjust to shifting ground conditions, making them more flexible than slab foundations.
