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Building your dream home can be a long process. One of the most important parts of this new construction is the foundation upon which the home sits. The foundation plays a crucial part in keeping the home stable. After months of looking at the home plans, when the foundation is laid, homeowners often wonder why it looks so small. For your convenience, we brought you the answer.
This optical illusion happens because the excavated hole is three-dimensional and looks big which makes the two-dimensional foundation look small. The foundation has no height which makes the area inside the foundation look smaller than it is.
A good contractor will construct the foundation exactly as the home plans specify. If you still have some questions about house foundations, don't worry. In this post, we'll discuss the topic in greater detail. Keep reading to learn all about home foundations and what they do.
What is the Main Purpose of a Foundation?
The foundation of a home (or any building) is constructed to support and stabilize the home on the ground.
With a solid foundation, the home will stand square and level for its lifetime. Every new construction requires a careful look at different factors to determine the best foundation to be used.
How is the foundation made for a house?
Before the foundation is constructed, the contractor will prepare the soil, making it level and steady. The foundation is usually a combination of concrete and concrete blocks reinforced with iron rebar.
The rebar gives strength to the concrete block, helping it to maintain its 90-degree vertical integrity. Some foundations are flat slabs of concrete called slab-on-grade (grade means prepared soil).
How Does the Optical Illusion Make the Foundation Look Small?
The foundation looks small because the owner has spent so much time looking at the paper or digital plans. Then, when the hole is excavated for the foundation it has depth, length, and width.
The hole looks so large. The foundation usually only has length and width and sits 1-3 feet from the edge of the hole, making everything look two-dimensional and small.
What are the Types of Foundations?
The three main types of foundations are slab-on-grade, crawl space, and a basement. The slab-on-grade is also simply called a concrete slab foundation.
The crawl space usually uses concrete footings and concrete blocks to lift the house 3-4 feet above the ground. This space often has gravel between the soil and the wood floorboards.
The basement foundation includes load-bearing walls made of concrete block and iron or steel rebar sitting on prepared ground.
The basement foundation has extra thick concrete in the sections that will be load-bearing. It will often have other block walls that are not intended to be load-bearing.
What are the Types of Basements?
Basements come in a variety of designs. Older basements were usually under 7 ft. high and unfinished with exposed floor bears, wires, and pipes. They were used for storage and possibly laundry. Modern construction requires 7+ ft. high basements.
Full basements have the same dimensions as the house above. Partial basements only share some of the dimensions as the house above.
Daylight basements have windows. Some daylight basements are walk-out basements with either a full side at ground level or with a stair to the surface. Bedrooms in basements are required to have egress windows for emergency exits.
What are Pier Foundations?
Some locations with clay or other moisture-laden soil may require a pier or caisson foundation.
A pier foundation has either a basement or crawl design but with the addition of piers. Piers are small circles or squares of concrete pads that are secured to the ground with treated wood or steel into the ground.
The piers are strategically placed at various points of the foundation to support the entire home.
Some metal piers are drilled all the way down through the soil to the bedrock itself to secure the home against changes in the soil.
If the water in the soil freezes, the piers secure the home to "float" a small amount but otherwise remain secure and square.
The Factors to Consider for a Foundation
Architects and home builders have to consider a few main factors to determine the best type of foundation to use for new construction. These factors are:
- Home design
- Exact location
- The type of soil
- The moisture of the soil and in the air
- Home Budget
As the foundation supports the entire home, the size of the designed home affects the foundation. A one or two-story foundation requires one set of specifications. A three-story home requires a stronger foundation.
Location and Climate
The architect needs to know the exact geographical location of the home so that they can choose the best foundation.
If the home is on a hill, the foundation must accommodate this. The home's location near a body of water can change the type of foundation used.
The location's climate affects the foundation choice. A home in a hurricane or flood plane needs a stable foundation to give stability in such conditions. Excessive heat or cold are other considerations.
The Type of Soil
The foundation anchors the home to the ground. The type of soil must be considered. Is the soil sandy or gravelly? How much dirt sits above the bedrock? Is the soil clay?
A big question that is considered is whether or not the soil is undisturbed. Undisturbed soil hasn't been moved, hoed, or had another building on the same footprint.
Undisturbed soil is considered stronger for supporting the foundation and the house itself. Soil that has been disturbed may require fill dirt, leveling, and/or stamping to make sure it is solid.
Read more: How Deep Are House Foundations?
The Moisture of the Soil and the Air
The amount of moisture in the soil is a crucial consideration. Clay holds a lot of water. In a freezing climate, the water in the clay will freeze and expand, lifting the home up and down.
The foundation must be designed for this yearly change so that the house keeps its frame square.
The moisture in the air is a consideration for the creation of mold and mildew in basements and crawl spaces. Architects can choose home designs that include good airflow to the foundation to keep mold and mildew from growing.
The Home Budget
Choosing the best foundation for a home always includes how much it will cost. A slab-on-grade foundation is the cheapest to use, followed by a crawl space, then a basement.
The most expensive foundation may involve using piers or caissons in the footings to secure by metal pipe the foundation to the bedrock deep below the soil.
Is the foundation the same size as the house?
The foundation is usually the same footprint as the house. Since the foundation is the load-bearing support for the home, it is the same size as the home. Decks and patios may or may not have a foundation underneath them.
How long does a foundation need to cure?
Concrete needs to cure to become strong. If the temperature is above 50 degrees, the concrete in the foundation will need a week to cure to the strength required for most building codes. It will take 28-60 days to fully cure.
If your foundation is using concrete poured into wooden or plastic forms instead of concrete blocks, the contractor may decide to wait longer than a week to give the foundation longer to cure.
How can I make my house foundation stronger?
When you are building your home, you can make the foundation stronger by:
- Putting a concrete layer under the concrete block.
- Keep the steel or iron rebar inside the concrete block from touching the fill gravel or concrete layer so moisture doesn't reach the rebar and allow rust to form.
- Make sure you test the soil type at different places so you know if the foundation requirements need to change if you have do have different soil types.
- For a slab-on-grade, use a water barrier between the slab and the gravel.
- Use moisture barriers around the foundation.
- Use piers to support the foundation.
- Make extra sure bolts attaching beams to the foundation are level.
How long do house foundations last?
Poured concrete, slab-on-grade, and concrete block foundations should last 80-100 years if properly constructed.
A yearly inspection of the visible foundation for cracks or crumbling is useful so that you can do maintenance to ensure your foundation lasts as long as possible.
The foundation of a new house is the solid support that gives the home structural integrity. Inside the excavated hole the foundation may look small.
This is an optical illusion. When the house is framed on that foundation you will begin to see the spaciousness of your new home.