There are some confusions among civil engineering students as well as professionals on relative differences among slab foundations, crawl space foundations and basement. So we have decided to write a post on this topic. First, we will go through the basic concepts of each of the topics and then we will summarize the relative differences between slab foundation, crawl space foundation and basement in a comparison table.
Slab foundations are usually around 6 to 8 inches thick. The house sits on the slab, which means no floor support system is needed. In an area where ground water and drainage is a problem, then a slab foundation is not a good option, but in areas with good drainage and few groundwater problems they are ideal. They are cheaper than most other foundation options and are often quicker to install, which means they keep house building costs down.
It is a space left in between home and the ground. Crawl space is typically between two and three feet, and stem walls extend from the footings around the perimeter of the foundation, though sometimes beams and piers are used instead. If there is a high moisture content and possibly poor drainage, then it is better to use a crawl space foundation as it helps to stop water from building up. They do require more excavation and more installation time than slab foundations, but are not overly expensive because of it. Some people are concerned about rodents getting into the crawl space under the house. But if there are spaces for cats to wander in, then it is rarely a problem. You can also check the crawl space repairing facts.
Many people prefer a house with a basement because they make excellent storage rooms, and they often offer a lot of soundproofing when compared with the rest of the house. Some people install windows and turn the room into a bedroom, dry storage area, or games room. They often improve the selling price of a house, and allow plumbers and electricians easy access to the house. They also make installing insulation a lot easier too. There are few basement foundations in places with a high water table, such as Miami, because the water may cause flooding or cracks in the foundation. If you are looking for an extra room, then a house with a basement may be suitable, but the ground you build upon and the local environment may restrict your choices.
Difference among slab foundation, crawl space foundation and basement
Let’s summarize the differences as slab foundation vs crawlspace vs basement comparison table for easy understanding as below.
They are ideal for places with less ground moisture.
They are perfect for homes with a lot of ground moisture.
They are ideal in places where the water table is very low.
Little excavation is needed to install a slab foundation.
A fair amount of excavation is needed to make a crawl space foundation.
A lot of excavation is needed to create a foundation basement.
They are a cheaper option, and more often are cheaper than basement and crawl-space foundations.
They are not expensive to install, but cost more than slab foundations.
They are the most expensive of all three foundation options, but offer an extra room and ergo push up the sale-price of the house.
Houses can be built faster because the foundation installation process is very quick.
They take a little more time to install than a slab foundation.
Basements take the longest to build and install.
Getting to the plumbing and electronics in the house can be very difficult.
A crawl space allows easier access to power cables, piping and under-floor insulation.
They often allow things such as piping and electronics to be accessed very easily.
No floor support system is needed with a slab foundation
Some people have problems with animals finding their way into the crawl space
The basement offers added functionality to a house by providing another room
Depending on the house design you have, it may be easier for rodents to enter your home.
It is more difficult for rodents to get into your house, but they may find their way into your crawl space.
It is often difficult for rodents to find their way into a basement, though holes in the walls may encourage bug infestations if food is left in the basement.
Maintenance and repairs are often more difficult with a slab foundation.
It is often very easy to repair and maintain a crawl space foundation because repair crews can access it easier.
Basements are easier to maintain and repair than slab foundations, but some repairs may be difficult to fix in rare circumstances.
It is harder for outside gasses and ground gasses to seep into the house.
A crawl space means it is slightly more difficult for ground gasses to get into the house because the airflow carries them off.
Ground gasses and contamination may seep into the house via the basement, so adequate protection may be needed in some areas.
Slab foundations may need repairs after 30-40 years unless they are installed in warm areas or rocky-ground areas.
A crawl space will need maintenance, but should last at least 40 years before needed bigger repairs.
A basement will need semi-continuous checking and maintain ace to be sure it is sound, but should last around fifty years before needing repairs.