Most homes in the United States are built on below-grade foundations, but agents should be trained in all types of foundations, including slabs, to be able to answer buyer questions. Let’s break down what a slab foundation is and why it might be a smart choice.
Knowing a few basic building principles will serve real estate agents well, making them more comfortable and confident when viewing. While agents don’t have to be experts, able to answer highly technical questions, it can make the presentation more interesting for you and your buyer.
For example, after entering a kitchen at an exhibition for the third time with the same group of buyers, it can become tedious and redundant to say, “This is the kitchen”. After all, the room has a stove, sink, fridge and hopefully a dishwasher – what else could it be?
Creating a dialogue with buyers about different types of construction and foundations can help you answer questions and build your expertise. As every day is new in real estate, it pays to have information at your fingertips.
Since most homes in the United States are built on below-grade foundations – basements or crawl spaces – it’s a good idea for agents to understand the pros and cons of each and understand the principle of a slab foundation.
What is a slab foundation?
Homes built without basements or crawl spaces are built on slabs, which are flat cement bases. Slab homes are economical to build because no excavation is required, eliminating the need for heavy equipment, energy expenditure, and transporting soil removed from the basement to another location.
A slab foundation reduces the impact on the site. Cinder blocks and bricks are not needed to support a slab house and only a cement floor or slab is poured, which can be done in a day. Building from a slab basement is less expensive than digging to build a basement.
Foundations are generally determined by the type of house being built, the type of soil and ground conditions on site, and the climate and part of the country where construction is taking place. Bedrock or solid soil is ideal for building slab foundations. Sand and clay are less ideal, as are places with excessively wet soil or prone to flooding.
Although slab foundations are quick to build, they can last 50 years or more.
How are slab foundations made
Slab foundations – also known as slab-on-grade or SOG – require pre-coordination of plumbing, electrical, and sometimes heating, ventilation, and cooling (HVAC) that are installed on the job site prior to pouring the foundation. slab.
Slab homes are less flexible than traditionally built homes, which add plumbing, electrical, and HVAC after the foundation is poured. Once the site is leveled, gravel or crushed stone is poured and plumbing and power lines are laid.
Large trees near the job site may have roots that over time will negatively impact the foundation, just as they would affect a basement or underground pipes in a house, so it is best to remove any that are too close.
A cement truck then comes and pours the cement, which will dry and be ready for construction between seven and 28 days. Steel bars, or rebar, are added to the slab before the concrete sets. These steel rods add tensile strength, the result being reinforced concrete (also called reinforced cement concrete).
Myth: Slab houses are cold
A common perception of slab houses is that they are cold. This is not the case.
Slab foundations have been used in the frigid climates of Canada and Europe for over 50 years and a new insulated foundation, a shallow frost protected foundation, is currently in use in Alaska.
Cement floor insulation is mandatory and radiant heating installed in the cement ensures warm interiors. Slab-on-grade foundations require skirt insulation that protects the perimeter of the slab, ensuring that it will never be subject to freezing.
Vertical rigid insulation on the outer edges of the slab that extends to the bottom of the foundation walls preserves heat. A “wing” of rigid insulation that extends from the foundation two to four feet also protects the structure from the cold. The right perimeter of the house loses less heat in the corners, so more insulation is needed in the corners to provide warmth.
Moisture in the ground can freeze when temperatures drop, causing ice crystals to form underground. Frozen water expands and ice “lifts” results. Uninsulated slab foundations can be damaged by ice heaving, which is why slabs were not used in colder climates in the past. Modern insulation and waterproofing materials have prevented ice from damaging the tiles so they can be used in all climates.
Slab foundations have evolved over time to be energy efficient, economical and environmentally friendly. In the future, with the advanced waterproofing and insulation options available, slab foundations will be used more frequently and more effectively than in the past.