What You Need To Know About Foundations

When you look at your house, do you ever wonder how it was built? How are the walls and ceiling held up together?

A simple look at your house could lead you to several questions that resulted from your curiosity as to how houses are built.

Do you ever wonder how the ceilings and walls of your house hold up together?

Houses Built According To Building Code
In the United States, more than 100 million housing units are built, the majority of which are single family dwelling units or in laymen’s terms, houses. The majority of these American homes are constructed using standardized building practices, from the foundations up to the interior finishing.

The United States is fortunate to have a set of uniform building codes applicable to all the states. Hence, the consistency on having homes that comply with the stipulations of the building code.

Foundations
Perhaps considered as the most critically important stage of house construction is when the foundations of the house are laid. With a properly-built foundation, it more than just holds the structure above the ground. The foundation also:

  • Keeps out moisture
  • Resists earth movement
  • Insulates against the cold
  • It determines how long a house would last standing safely on the site

Good Foundation Design And More
With a poorly-designed and built foundation, any structure is bound to “sink”. Good foundation means footings made of poured concrete and steel-reinforced foundation walls. Buildings or houses that have lasted for centuries are those built with laboriously assembled foundations of mortar, brick and stone.

Buildings or houses constructed with even the most modern and durable fastening materials such as stainless steel bolts, and using the latest construction methods will not be spared from collapsing if the foundation designs are weak to begin with.

The house’s foundation takes all of the load from the roof to the walls to the floors, and transfers them into the soil where the house stands. Hence, it is important that builders pay attention when laying the foundations of the structure.

A lapse in the proper laying procedures of the foundation could result in a failure of the building or structure shortly after it has been constructed. Every detail – soil conditions, backfill quality, water tables, properly compacted base, properly set up formwork, and concrete free of voids – contributes to having a solid foundation for your house.

The type of foundation your builder designs for your house will depend a lot upon your particular situation. Basically, there are three types of foundations:

Basement Foundations
If you are from the North, your house must have been built with a basement. A basement may be thought of as an extruded crawl space type of foundation. In the East and other older areas, basements are popular because of the additional space it provides the family with. A basement is also one of the most cost-effective ways of expanding your house, as it can be easily converted to become a living space.

Crawl Space Foundations
A crawl space or raised foundation is common in houses found in the middle part of the country where the frost lines are not as deep. A crawl space foundation is built above the ground, with just enough space allowed for crawling underneath. The crawl space foundation should have at least 2 feet of clearance from the ground so that an average person can crawl in to take care of the house’s mechanical systems.

Crawl space foundation allows for at least 2 feet space underneath for a person to crawl in to take care of mechanical systems.

Slab Foundations
Houses in the South are most likely built with a slab foundation. This is usually a flat concrete pad poured straight onto the ground. This foundation type requires little preparation on the site and little formwork for the concrete. Slab foundations are very efficient and cost-effective. In this particular area, the soil conditions may not allow basement type of foundations. Slab foundations uses concrete instead of wood to provide support to the weight of the structure.

Reasons For Foundation Failure
Designing a good foundation is not what makes a house or structure last for many, many years. Your house may have a well-designed foundation but could still fail due to the following:

Nonporous Backfill
Foundations may fill if backfill used is soil loaded with clay or organic matter. In this case, soil holds water like a sponge and that increases the risk of having cracks in the foundation when the soil expands and freezes.

Rushed Curing
Concrete needs approximately four weeks to cure to full strength of 3,000 psi. If concrete is not allowed to cure slowly to reach proper strength, it could cause the foundation to fail.

Inadequate Compacting
Crushed stones that have not been adequately compacted before the slab is poured are likely to settle or crack, causing the foundation to fail.

Concrete Pouring Interrupted
Concrete forms should be filled with concrete in one pass. Any interruption in concrete pouring can result in a “cold joint” between the fresh concrete and the previously poured part, creating the likelihood of cracking and leaking.

Article Sources:
http://www.diynetwork.com
http://www.thisoldhouse.com
http://home.howstuffworks.com
http://www.houzz.com

Lisa Myers
 

Is a blogger with an interest for all things mechanical. She is a full-time mom with three active boys, who loves encouraging them to explore the world of science and engineering. They spend a lot of time together playing with Legos.

Click Here to Leave a Comment Below 5 comments
Oliver

Buildings have extensive direct and indirect impacts on the environment, as far as I’m concerned. During their construction, occupancy, renovation, repurposing, and demolition, buildings use energy, water, and raw materials, generate waste, and emit potentially harmful atmospheric emissions. These facts have prompted the creation of green building standards, certifications, and rating systems aimed at mitigating the impact of buildings on the natural environment through sustainable design. But still, there are so many older homes built decades ago that are not so green.

Reply
James

If you are having a home built, there are things you need to know (and ask your builder) to ensure your home has a solid foundation. Footings and foundations are to homes what feet and legs are to the human body: footings anchor the home to the ground and support the foundation, which in turn carries the weight of the home. My father had a home built and it was a learning curve he had to experience.

Reply
Moses

As is well known by most homeowners in North Central Texas, the foundations for their homes are often times constructed on expansive clay soils. The problem is that clay soils shrink when they dry out and swell when they experience an increase in its moisture content and this shrink / swell of the soils can easily push a slab foundation around. This has cost Texas homeowners millions and millions of dollars in repairs. I wonder if there is a viable solution for the home owners in that region.

Reply
James

This article has discussed various types of issues that have to do with the foundation of home building. But one aspect that is troublesome and complicated is that of foundation movement can be categorized into two types: foundation settlement (the most common) and foundation upheaval (the most difficult to remedy by foundation repairs). I recently learned about a homeowner of a new custom home (costing about $1mm) where the foundation heaved upwards over 5 – within the first year! The slab was constructed over drilled concrete piers; which is the type of foundation I would design for myself if I ever built a new home (shoot me dead first).

Reply
Luther

I have learned that support cost is the cost of the installed or constructed foundation element (or system) divided by its allowable load. Accounting for set-up in pile design can result in using smaller hammers, smaller pile sections, shorter piles, higher capacities/allowable loads, and therefore more-economical installations than otherwise possible. Geotechnical characterization of a pile-foundation site (anticipated driving behavior, set-up magnitude and distribution, and long-term capacity distribution), combined with installation costs for various pile options, can be used to select cost-efficient pile installations based on support cost.

Reply

Leave a Reply: