According to the United States’ Census Bureau’s Survey of Construction, basements are on a downward trend.
- In 2000, 40% of homes were built with basements.
- By 2013, that number was 32%.
This shows a 20% decline in basements, which is significant and suggests a major trend away from basements for new-build houses. But why is that? The advantages of basements are fairly clear – they represent additional space in a house that can be converted into usable space. Failing that, they are useful areas to use either as storage or as a home for appliances, away from the main body of the house.
What does seem to emerge when you analyze the data is that there are stark regional divides throughout the United States. This is driven by a number of factors:
- Climate
- Soil type
- Basement flooding risks
- History and culture
Each of these also overlaps with geographical differences within the US. This guide will discuss why 68% of new homes don’t have basements, and why the presence of a basement is very much dependent upon location across the United States.
WHICH AREAS HAVE BASEMENTS?
On the basis that basements are declining, we need to examine the areas where they remain a common feature in new-build houses. Generally, the divide across the country is regional, suggesting there is a combination of cultural and climate factors at play.
THE WEST
The Western part of the country (including the Midwest) is the area where basements are most popular. One region in particular – the West North Central States – is the heartland of basements. This region consists of the states west of the Mississippi and east of the Rockies.
The seven states of this region are:
- Iowa
- Kansas
- Minnesota
- Missouri
- Nebraska
- North Dakota
- South Dakota
These states remain the holdouts against declining basement numbers, with roughly 40% of new homes built here containing basements.
In a stark division, the states of the East North Central subdivision – many of which lie just across the Mississippi from the West North Central, have a 20% figure for new-build basements.
If you live in the following states, you have half the chance of having a basement in a newly-built home than if you live on the other side of the Mississippi:
- Illinois
- Indiana
- Michigan
- Ohio
- Wisconsin
What is striking about this is that states in either subdivision have broadly the same climate, with very cold winters and warm summers. This suggests that climate is less of a factor than culture may be.
THE SOUTH
In the southern part of the country, basements are rarer than in the north. The vast majority of homes in the South have either no basement whatsoever or have an unfinished basement. To illustrate this point, the following four states, which form the ‘West South Central’ division have a basement inclusion rate for new homes of 0.05%.
These states are:
- Arkansas
- Louisiana
- Oklahoma
- Texas
To put it another way, if you buy a brand-new home in Kansas, you are 800 times more likely to have a basement than if you buy a brand-new home in Oklahoma.
THE COASTS
Homes near either the Atlantic or the Pacific Coasts are also less likely to have basements than those of the 40% of the West North Central region, although there seems to be less of a clear delineation in this respect.
Many older homes on the East coast do have basements, although new-build homes follow the national average rather than show stark regional divides.
WHY ARE THERE FEWER BASEMENTS IN THE SOUTH?
The statistics above all show that the real divide in basements is north-south. Although there is some variance across the East and West, the real drop off occurs when you cross the Mason-Dixon line.
90% of homes north of the line have basements, and less than 1% of those to the south do.
Partially this is due to climate, although in most cases it is due to the conditions on which the house is built.
This centers on two main factors: the soil content and the water table.
SOIL
Across the southern part of the United States, one of the most notable features of the south is the sandiness of the soil. Across the country, there is a rectangle of sandy soil; if you draw a shape, with corners in Maryland, Florida, and northern and southern California, you have drawn a shape inside which the soil is extremely sandy.
In these conditions, home builders favor either an outdoor shed or attic storage, rather than a basement.
WATER TABLE
In addition to the sandy soil, in much of the south, the water table is high, making the soil extremely damp. In many parts of the south, this means that there is swampland or wetlands. Where the water table is high, it is simply not feasible to dig too deep underground. In Florida, Alabama, Louisiana, and Eastern Texas, the soil is particularly damp, which explains the minimal number of basements there.
Basements generally require a depth of eight or more feet. In southern Florida, the water table is roughly three feet below the surface, neatly encapsulating why basements are not feasible.
HOW DOES HOUSE SIZE AFFECT BASEMENTS?
There are certain statistics that demonstrate the impact of different house sizes on basements. For example, large houses (‘large’ here refers to houses with five or more bedrooms) rarely have finished basements.
Only 5% of these houses have basements that have been totally finished.
Indeed, only 18% of large houses have basements at all, well below the national average of around one third.
This certainly lines up with the idea that the large homes have less need for a basement. Since the primary function of a basement is usually storage – larger homes have more adequate storage elsewhere.
RENTAL VS. OWNERSHIP
One of the most dominant trends of the last twenty years when it comes to home building has been the decline of ownership. The average price of a house as a function of annual salary has increased across the country. This was compounded by the 2008 financial crisis and the resultant increase in difficulty for accessing a mortgage.
Homes built for rent are roughly 25% less likely to have a basement than those that are built by the owner. This would go some way to explaining the wider decline in basements across the country, in that it tends in the same direction as homeownership.
Renters are less likely to remain in a place for decades, meaning their need for major storage is less than a homeowner, making a basement less necessary.
WHAT ARE THE REASONS TO NOT HAVE A BASEMENT?
What each of the above statistics demonstrate is that even in areas where basements are possible and traditional, their usage is declining. The reasons for this tend to be rooted in very simple details.
SOIL
Even in parts of the country that don’t have sandy soils, there are large areas where the soil composition is especially clay-heavy. Clay soil can make building basements difficult because of the dramatic expansion and contraction as it takes on water. This places great lateral pressure on basement walls, which would almost certainly, and repeatedly, lead to water in the basement even if there was no rain.
In parts of the country – particularly in segments of the south – there is only a shallow layer of soil over a limestone bed. Although limestone is a soft rock, it is still hard to dig a basement from.
In addition, where the soil is in a loose pack, builders may have to add lime to the ground before building a basement to offset the moisture level.
CLIMATE
One of the main reasons why northern buildings often have basements is the depth of the frost line. When you build a home, the foundations need to be below the depth of the frost line. In the north of the country (and particularly in the midwest) this requires deep foundations, thus making a basement far more practical.
In most of the rest of the company, there is less of a need to dig that deep, making a basement an additional expense. For more on foundations, go to our pages on types of home foundation and foundation waterproofing.
COST
Ultimately, when it comes to home building, everything comes down to cost. In the north there are fewer financial obstacles to basements, making them more prevalent. Indeed, in the north, basements are driven by the need to dig deep foundations.
In the rest of the country, they need to be actively (and often expensively) dug out. This provides a major economic rationale for a state-by-state difference in approach to basements.
So, given all that is discussed above, and the overarching trend, does that mean we are heading to a basement-less future? The answer is probably not. Basements serve many useful purposes in the parts of the country where it is structurally possible to build them, including that they increase the capacity of a home without increasing its footprint.