In a previous video we discussed the differences between slab on grade and pier and beam foundations,
the two most popular types of foundations.
In the comment section of that video, a lot of you requested a followup video on basement
foundations.
Basements are popular in Northern States, but not as popular in the West and here in
the South.
In fact, the overall popularity of basement foundations has been dropping over the past
20 years.
The National Association of Home Builders says that 65% of all new homes constructed
in 2020 had slab foundations, while only 22% of them had full or partial basements and
12% of them had crawl spaces.
The gap between these foundations continues to grow.
In this video, we’re going to look at how basements are constructed, different types
of basements, and their pros and cons and the reason for their downtrend.
Basements serve the same purposes as other foundation types; they distribute a building’s
weight evenly, they secure it into the ground and they keep moisture out.
The most common type of basement construction is poured concrete.
Forms are used to hold the wall in place as the concrete dries.
These can also be poured concrete in ICF or insulated concrete forms.
The least expensive option for basement construction is concrete masonry units reinforced with
steel rebar.
These walls are faster to construct but are more susceptible to water leaks.
To save time on site, builders may precast concrete panels in a factory and transport
them when they are ready to be installed.
Stone or clay tile walls can be found in older or historic homes.
Ground water can seep into the basement fairly easily.
Now let’s look at the various types of basements
A full basement matches the perimeter of the house above.
So, if the ground floor of the house is 2000 square feet, the full basement's square footage
is also around 2000 square feet.
A full basement consists of structural foundation walls that bear on foundation footings running
along the perimeter.
Footings usually extend below the frost line, the depth to which the ground freezes in winter.
Full basements can be insulated and installed with drywall and flooring, providing living
and storage space.
They can also be unfinished or uninsulated with bare walls and floors.
Full basements usually lack windows, but if they have them, they’ll be small and at
ground level.
They are the most expensive foundation and they are susceptible to mold, mildew and moisture.
Next are partial basements which have a full height space underground, but do not extend
under the entire perimeter of the house.
They have the same mold issues as full basements.
Daylight or walkout basements are built when the building rests on a slope: One side of
the basement is fully submerged, while the other is aboveground.
As the name suggests, daylight basements can have large windows and doors to bring in natural
light.
They aren’t as susceptible to mold, mildew or moisture.
Daylight basements are easier to convert into living spaces.
They aren’t dark and dingy like full basements and you can include a separate entrance, a
necessity if you plan to rent out the space.
Crawl spaces are a type of basement with limited use.
Crawl space foundations have a small protected space between the ground and base of the building.
They are deeper than standard foundations and more shallow than basements.
They cannot be converted into finished basements, but they provide easy access to piping or
plumbing.
They also encourage more airflow underneath the building, which helps keep things cool
in warmer climates.
Crawl spaces are the least expensive type of basement foundation since they don’t
require as much excavation.
Lastly, a cellar is a room underground that is often used to store canned goods, fruits,
vegetables, wine or general storage.
Now let’s look at the general advantages of basements.
The first and probably the most important is access to utilities like plumbing, electrical
wires and even under floor ventilation systems.
This is a huge advantage over slab foundations where you need to break up the concrete to
get to any utilities underneath.
Repairs and replacements are cheaper and easier with basements.
Finished full basements can boost home values by increasing the usable footprint.
A full basement with a 7 or 8 foot high ceiling can be converted into a home gym, office,
play area, home theater, or just left for storage.
Basements can be energy efficient.
They are naturally insulated by the earth so they need less energy to heat or cool rooms.
Basements also provide shelter incase of a tornado or hurricane so don’t find yourself
in this situation.
Even with all these advantages, there are many drawbacks to basements which is causing
a downtrend in their popularity.
The first and most obvious is the cost of building basements.
Most of our decision making in life comes down to cost.
In the north there are fewer financial obstacles to basements, making them more prevalent.
In the rest of the country, the cost to dig out soil or rock is just too expensive.
Basements can also take longer to build and require heavy duty equipment like excavators,
cranes, and forklifts
Soils play a big role in the feasibility of building basements.
There are large areas in the US with clayey soils.
Because of the small size of its particles, clay is good at holding water.
It also dramatically expands and contracts as it takes on water.
This puts immense lateral pressure on basement walls, which would lead to water in the basement
even if there was no rain.
In other parts of the country there is only a shallow layer of soil over a limestone bed.
Although limestone is a soft rock, it is still difficult and expensive to dig into for basement
construction.
A high water table can also prevent the construction of basements because the soil is extremely
damp.
Alabama, Louisiana and eastern Texas have a lot of swamp land or wetland territory which
are not compatible with basements.
Basements require a depth of 8 or more feet.
In southern Florida, the water table is just 3 feet below the surface.
Before we move on to other disadvantages of basement foundations, I’d like to introduce
the sponsor of this portion of the video, Skillshare.
Skillshare is an online learning community that helps me learn something new every day.
It has thousands of inspiring classes for anyone who loves learning and wants to explore
their creativity and learn new skills.
From photography and illustration, to woodworking, storytelling, and more, you can find classes
that will match your goals and interests.
I recently took MKBHD’s class on YouTube success.
Even though the subject matter of his videos is different from mine, he had a lot of invaluable
lessons.
If you’d like to check this out, the first 1,000 people to use the link in the description
or my code belindacarr will get a 1 month free trial of Skillshare.
Now back to the video.
Another disadvantage of basement construction is dealing with the climate, in particular,
the frost line.
As we briefly mentioned earlier, the frost line is the maximum depth of ground below
which the soil does not freeze in winter.
When you build a home, the foundations need to be below the depth of the frost line.
Northern states have a deep frost line of 60 inches or 5’.
They require deep foundations, thus making a basement far more practical.
In southern states, the frost line is less than 10 inches below the surface, so there
is no need to dip that deep.
Basements are an unnecessary and additional expense.
Another very important factor leading to the downtrend of basement construction is the
risk of leaks, mold and mildew.
Basements are often exposed to more water than standard foundations.
It’s important to have a sump pump to remove water from your basement.
It’s also important to insulate water pipes and keep the foundation crack-free.
Proper grading around the house is important to let water flow away.
Missing gutters and downspouts can cause water to puddle and seep into cracks in the foundation.
There’s one more reason why basements are declining in popularity.
Since 2008, the homeownership rate has stayed below 65%.
More people rent houses or apartments in complexes.
This is either by choice or because they have been priced out of the market.
Basements can be a liability because they are susceptible to moisture, so landlords
will want to stay away from them.
In conclusion, the rising cost of materials and waterproofing issues are two of the main
reasons why basements are no longer popular.
It costs more to build than the value it will add to the property.
When I lived in Cincinnati, DC and New York, the buildings I lived in had basements that
were usually dark and dingy, like a laundry room.
But I haven’t seen them here in Texas.
I’d love to have a basement as an acoustically insulated recording studio for videos and
podcasts, and as a shelter during tornado warnings.
Let me know if you’ve dealt with moisture issues in basements in the comments below.
I’ll link my Patreon page in the description.
If you can support me, I’d really appreciate it.
A big thank you to everyone already supporting me.
I’ll link all my sources in the description below and on my website.
Don’t forget to hit that like button, subscribe button and the notification bell too.
Thanks for watching.
See ya