Pros and Cons of Basement Foundations

Ranging from Functional Storage to Sleek Living Space, Is a Basement Right for You?

 

Why would a basement be an item on the “wish list” of buyers looking for a new home?

The basement has a variety of purposes, including the obvious: storage space and more living space. For homes with a small footprint that cannot expand out and around the property, a basement offers the flexibility of building down – to maximize the square footage of the main living areas.

Think of all the possibilities a finished basement provides: a workshop, laundry room, in-law suite, guest quarters, game room, entertainment center, home office, fitness center, second living room, or whatever a person wants. And should the home not turn out to be a “forever” one, there’s the potential to increase the property’s value when it’s up for sale.

 

Realtor surveys show that finished basements rank next to kitchen and bathroom renovations in return on investment. On average, finishing a basement gives the homeowner a return of 70% to 75% of the investment: if you spent $1,000 on improvements, it would increase the property's value by about $700. If you spent $10,000 on improvements, it would increase the value of the property by about $7,000.”

One more advantage of a basement is having a convenient shelter, especially for those who live in the Midwest and experience all those tornado warnings. The basement serves as a “safe room” during these instances and other extreme weather conditions.

 

But there are a few glitches, too.  

• If your basement is primarily unused – aside from laundry purposes – the basement is really wasted square footage.
• Be prepared – though it's not inevitable – for possible water damage and moisture accumulation at some point – especially after several days of heavy downpours.

 

Basement as Foundation

Simply put, a home’s foundation is the load-bearing portion of the structure – typically built below ground. Whatever foundation you choose, keep in mind that it must do these three things very well: support the structure above, keep out groundwater, and act as a barrier to water and soil vapor. There are three common foundation types:

Slab, which is basically a concrete platform – built on grade with a deeper perimeter footing underneath – on which a house is built

Crawlspace, which consists of footings and short columns that are set to support the house structure and a perimeter wall to enclose the foundation area

Basement, which uses full-height walls extending below ground to support the perimeter of the house and precisely placed interior columns to support beams across the length and/or width of the house.

The basement foundation, which is an excellent way to anchor the property to the ground, is popular because of the options it provides for additional living areas and storage. The basement may be fully underground. If you’re building on a sloping lot, it may be partially exposed to daylight or even fully exposed on one or more sides, allowing you to walk out onto a patio (walkout basement). These latter basements are more likely to be finished as living space. Basements are also the most expensive foundations because they require more materials and more time to build.

 

In construction terms, the basement is built by excavating eight or more feet belowground (depending on the basement headroom desired), then pouring a concrete floor and constructing walls that enclose the space. Today, contractors typically use poured concrete for the walls to eliminate problems related to structure and moisture.  

 

Advantages

Here are several advantages of a basement foundation over a slab or crawlspace:

• Additional square footage can be made livable at a much lower cost per square foot.
• A finished basement creates an energy-efficient seasonal living space for smaller homes – it stays warm in the winter months and cooler during the summer season.
• A variety of options for expanded living spaces (recreation rooms, crafts room, man cave, additional bedrooms and bathrooms, and more) – plus storage are available.
• More privacy is inherent – particularly if the basement is a dedicated in-law/guest suite.
• Tremendous buyer appeal results, particularly if it’s fully finished, increase the resale value of the home.
• Basements provide shelter during tornadoes, hurricanes, and other severe weather elements, resulting in protection from the elements for both residents and the home.
• There’s easy access – and cheaper cost – for repairs. Technicians can get in and out of a basement much easier than crawling in a crawl space or digging into a slab.
• Flexibility to be built on a sloping grade – ideal for a walkout basement.
• Wood floor structure on the main level is much more flexible and forgiving than concrete.

 

Disadvantages

There are also a few drawbacks.

• A basement is more expensive to build than a slab or crawlspace.
• There’s a higher likelihood of a radon issue – but it can be avoided/prevented by using radon-resistant techniques and installing an active radon mitigation system.
• There's potential for flooding without a sump pump (which can be eliminated by ensuring a natural path for drainage from the footings).
• Lack of natural light (if it’s not a walkout/daylight basement) presents a challenge to finding creative ways to bring light into the space.
• A sloping lot is needed if you want to build a walkout basement.

 

Basement Construction

There are several ways to build basement foundation walls. Some are less expensive than others; others may be specified by engineers based on local soils or are typically used more often in one locality than another. And sometimes, it may just come down to personal choice.

 

Poured Concrete

The most common – and most popular – type of basement construction, poured concrete, is simple and sturdy and begins with the pouring of a footing for the foundation. Builders use forms to contain the poured concrete and hold the walls in place as they dry – resulting in strong basement walls that don’t typically cause many problems. Benefits include

• Resistance to cave-ins caused by water and earth pressures because of the solid concrete
• More fire resistance because the solid concrete is dense and joint free
• More resistant to water because it has fewer and smaller voids than concrete block.

 

Concrete Block

Less expensive than poured concrete and very popular in certain parts of the country, concrete-block construction involves using blocks of masonry, which can be built in less total time than a poured concrete wall. To reinforce the strength of the walls, builders typically use steel rebar.

A big disadvantage of concrete block walls is their susceptibility to water leaks along the floor and wall joints. Not only that, but water can seep through the mortar that holds the blocks together – and remain in the hollows of the blocks even after the surrounding soil has dried.

 

Precast Concrete

Residential builders who want to save time and money turn to precast panel walls, fabricated offsite, and then transported to the building location when they are ready to be installed. Not as common as poured-concrete construction, precast panel walls are made of a high-strength, low-water concrete mix that makes them more water-resistant over the long haul. If there is water damage, it is usually along the joint between the walls and the floor.

 

Wood

Pressure-treated wood may also be used to construct a foundation. Pressure-treated 2x6s or 2x8s form a frame to which pressure-treated plywood is secured as the foundation walls. A wood foundation is much less expensive than a foundation made using a concrete product. It may be used in remote areas where it would be difficult to transport concrete, for example, but it is not generally recommended in normal circumstances.

 

Stone

Finally, there are stone walls, which are basically found in older or historic homes when other construction materials were not available. These walls can be strong, but when there are cracks and gaps in the stone walls, the biggest potential risk is groundwater seeping through to the basement. To solve this problem, builders install an interior perimeter drain system.

 

Short History of the Basement

The basement was typically referred to as a cellar in its early days … when it was mostly a root cellar – an underground or partially underground space used to store crops like vegetables, fruits, nuts, and other food products on a farm. In the days before refrigerators, root cellars, which were cooler than most of the other parts of a home, were the perfect spots for items that needed to be kept at lower temperatures.

As cellars evolved into basements with concrete walls and floors, their functions were still boring but necessary – a “home” for the boiler and/or the washer and dryer and space for extra storage. These early basements did not even consider the bad effects of mold, mildew, and moisture problems. It was only later in their construction that builders incorporated drainage and air circulation.

In the 1950s, when industrialization in the U.S. was in full swing and technology advanced, things started to change in basement construction. By then, most new homes – especially in parts of the Midwest and the Northeast – integrated the basement in their overall home design.

So whether the basement is simply an upgraded root cellar intended for storage, a completely finished and furnished extra living space, game room, home gym, family/theater room, or an all-important shelter in tornado-ridden areas, it has a wide variety of purposes for today’s homeowner.

 

Basement or No Basement – Where Do You Go from Here?

Today, savvy potential buyers come prepared with their ideas and needs/must-haves for a new home. And residential builders and designers are very cooperative – providing flexibility to allow creative use of the lower-level living space to accommodate growing families. They are also there for advice and recommendations – before clients choose a foundation and move on to the next step of planning.

 

For example, the first thing that Sam Morgan, a certified professional building designer from SW Morgan Fine Home Design, tells customers when asked about basement foundations is to look first at whats most common in their area. And if it’s most common to have a basement, “maybe it’s worth considering even if youre just going to leave it unfinished,” and let somebody else complete it down the road.

Morgan also adds that homeowners who have resale in mind should not design or build their house for the next owner but build what they want and let the next owner make the changes.

So are you ready to decide if there’s a basement in your present – or future? If you’re in the market for a home, keep a checklist of foundation options and design ideas to discuss with your builder – to ensure that your choices and plans for a lower-level living make sense and are appropriate for your property size, location (including topography), and area of the country.

Now that you have all the basics of basement foundations and construction squared away, it’s time to envision that amazing basement space and focus on what you really want in it. Keep in mind that you can be creative when planning its design and that while it’s basically “life underground,” it can be airy, bright, comfortable, sophisticated, and family-friendly.

 

Footnote: The lead image in this article is the walk-out basement in a breath-taking 2-story, 7,404-sq.-ft. Craftsman style home with 4 bedrooms, 4 bathrooms, 2 half-baths, and covered decks on both levels. For more on the basement and all its amenities, go to Plan #161-1017.