Building and planning a house from scratch is a complex and often perplexing process, and laying a foundation is one of the most essential steps. But after that is done, how is a house attached to the foundation?
Most houses use anchor bolts to attach the house to the foundation. But this can vary depending on the type of foundation the house has. For example, in crawl space foundations, the house is attached through piers or columns.
Read below to find out more about the different types of foundations and how they are attached to the house.
Foundation Types
There are different types of foundations, and this section provides an overview of each.
Full Basements
The basement’s perimeter is the same as the rest of the house. Therefore, assuming the first floor of the house is 800 square feet, the basement is probably also 800 square feet in size.
A full basement has bearing walls that rest on foundation footings, which go around the entire basement’s perimeter. In most cases, footings go beneath the frost line, which is the depth at which the ground freezes during the winter.
The value of a house increases significantly when the basement has a ceiling height of seven feet or more. It can be used as-is for storage, as a home gym, a playroom, a media room, or even as a bedroom.
Crawlspace Foundation
Crawl spaces are formed by short foundation walls resting on footings. The walls can be quite low, making it necessary to crawl through, or they can be four feet high, offering ample space for storing items and, in certain cases, a furnace or other pieces of machinery.
Floors in crawl spaces are often constructed at or above the grade. In other words, the lowest part of the crawlspace (as opposed to the upper floor of the house) is at or above ground level.
Crawlspaces are sometimes constructed below ground level, like a basement. Steps must be taken to ensure that flooded water can drain. Flood insurance rates may be more expensive for people whose homes are on the ground level or have crawlspaces below ground level.
Crawlspaces tend to be unheated and may have some ventilation provided by small vents that pass through the foundation walls. Crawlspace foundations present unique challenges when it comes to moisture management and preventing water seepage and leaks.
Crawlspace foundations are more cost-effective than full basements since less work is involved in excavating the site and constructing the foundation walls. The walls of a crawlspace are normally constructed with concrete blocks and either poured or mortared together, just like the foundation of a full basement.
Slab-On Foundation
A slab-on-grade foundation consists of a flat, level concrete slab placed directly on the soil. The term “slab” represents the large, flat, and solid concrete floor, while the term “grade” represents the ground level.
Slab-on-grade foundations are generally used in warmer climates where the earth does not freeze and thaw, which can cause cracks in the concrete and foundation movement.
Slab-on-grade foundations are less expensive than full basements or crawlspaces and can provide better protection from termites, which are prevalent in warmer areas.
How Is A House Attached To The Foundation?
Anchor bolts are often used in both wood and steel-framed buildings to attach houses to their foundations. When the concrete foundation is being poured, these bolts are placed in the wet concrete so that their ends will extend above the foundation.
After that, nuts and washers are used to fasten the sill plate, which is the lowest horizontal part of the house’s structure, to the anchor bolts. This secures the home to the ground, so it won’t move during quakes or strong winds.
In homes that have crawl space foundations, the floor structure is frequently held in place by piers or columns that are supported by footings. These piers are secured to the floor framework of the house using beams and joists, which helps to keep the home secure above the crawl space.
A slab-on-grade structure has the same meaning as its name suggests: a concrete floor poured at ground level and used as a foundation for the home’s primary living areas. At the perimeter of the slab, there are shallow footings that support the house’s walls.
Role of Soil in Foundation
The real load-bearing system that keeps the house upright is the material beneath the foundation. Certain soil types—like sand and gravel—may be suitable for structural support. Whereas loose fill, for instance, would collapse under the weight of a car.
Soil that is high in clay tends to expand and contract with the weather, which can lead to foundation movement and wall cracking from internal pressure. The Midwest and the Western United States are more prone to having poor, unstable soil, but it can be found anywhere.
The best kind of soil to have under a foundation is one that hasn’t been disturbed, is porous enough to promote excellent drainage, and is stable and strong enough to offer proper support.
In order to replace poor soil or provide a flat area for the foundation, it is sometimes necessary to bring in additional soil. When using fill soil, it’s important to compress it so that it works like undisturbed soil. A geotechnical engineer ought to be present throughout the compacting of fill material.
Common Problems With The Foundation
In this section, we cover some common problems related to the house’s foundation.
Water or Moisture damage
When it comes to problems with buildings, water is by far the biggest culprit. The easiest way to protect your home’s foundation and other parts against water damage is to keep water (both liquid and airborne moisture) out of them.
Gutters and downspouts should be installed to divert water from the roof away from the house’s base. A good rule of thumb is to have downspouts extend out at least five feet from the building’s base.
Cracks
In most cases, a concrete foundation slab or wall with a few hairline cracks doesn’t need to be fixed. Larger cracks, however, may signal an issue that needs the attention of a contractor with expertise in foundation or masonry repair.
Conclusion
Building a house from scratch takes a lot of understanding of the entire process. Luckily, you won’t have to look further for answers when it comes to attaching the house to the foundation, thanks to our detailed guide above.
