Your Home's Foundation
Your new home will need to be placed on a foundation that supports the entire structure while protecting it from groundwater and moving soil. Even beyond this basic idea, there are many different kinds of foundations to consider depending on what you want to achieve.
Some offer space and others affordability. Some work better in rock areas and others in loose soil. Once again, knowing the plot you will be building on is key to making the right choice regarding foundation types.
Piers are concrete blocks placed in or on the soil which have a bracket on top to hold the beams at the bottom of the house. Most often these are trapezoid blocks with flat tops, but they can also be long beams that are driven into the soil.
This means the house is essentially lifted off the ground by anything from a few inches to a foot, which promotes a healthy flow of air and removes the house from direct contact with the ground, preventing cold soil from transferring the heat into the home. However, this will also prevent the house from being cooled by contact with the ground in summer, so this is best reserved for somewhat colder climates.
Placing blocks on top of the soil is best done when the soil below is mostly rock. It would be expensive to drill or blast away the rock to place any other foundation, so piers can then be used to place a home with little or no ground work.
Conversely, placing the house on long piers anchored into the ground is a great solution if the ground is very loose or moves, like marshland, clay or sand. In these cases, the piers provide stability and prevent the house from being shifted when the ground does, preventing damage to the walls.
While relatively inexpensive and quick to build, this foundation does little else. There is no opportunity for storage underneath the house. Because the area underneath can be attractive to animals, you also need to cordon it off to prevent your home's foundation from being an animal's lair.
This foundation means that the house is not directly connected to anything; it also means that you will need to add extra protection to electricity and plumbing, all of which will bridge an open space somewhere as it leaves the house and enters the ground.
A flat plate of concrete is poured inside a casing that has the same shape as the house. It rests partially inside a cavity dug into the ground, and rises a few inches above the soil level. As it is being poured, spaces and tubing is left to allow plumbing and electricity cabling to be pulled to the house after the foundation has set.
Plate foundations are relatively cheap, but they are somewhat involved to pour. There is some groundwork, some casing and then the pouring of the concrete. It needs to be tended well so it can dry up without cracks or air bubbles that would weaken the structure. This takes time, so it takes more time to build than a foundation of piers.
A plate that has additional space in it, so you can enter it and check out the state of the tubes and foundation, is called a crawlspace. It will have one or more entries from the house, and while you cannot use these spaces, they provide additional insulation against moisture and cold.
Because it sits in contact with the ground, it allows for the soil to help regulate the flow of heat; heat rises up from the ground in winter, and draws in heat during the summer. The plate foundation is a solid choice for any type of plot, as long as it is not excessively wet (such as marsh).
The main downside of a plate foundation is that it features no storage space, as it is a flat sheet of concrete. It makes up for this by being affordable and easy to maintain.
With a cellar foundation, a large recess is dug or blasted into the ground, and a wooden frame is made inside of it. Once concrete is poured into this frame and it has had time to set, the frame is removed leaving a large concrete box. This box is largely hollow, and this space can be used as storage or additional living space. The walls of the box form the support for the rest of the house.
A cellar is a great option if you have solid ground to work with, but it can be vulnerable to moisture. Because of this, a cellar needs protective layers and runoffs to protect it from moisture creeping into the wall. Not only would that increase the moisture levels in the rest of the house, it can also damage any wood used in the house above it, and promotes the growth of mold and fungi.
But these extra costs and additional work load are more than compensated for by the option of having additional underground space, which is temperature-controlled. It will be roughly the same temperature throughout the year, and because it's usually cool and dry it's a great place to use for storing food. Many people also use the space as storage, or to keep the washer.
If you want to make a cellar space more usable, consider adding a cellar door going in from the outside, and one or more cellar windows. These differ from regular doors and windows in that they are dug into the ground. This will offer more light and access to the cellar, but be careful of snow and rainfall. Without good drainage these dug-out spaces quickly become pools!
Cellar spaces are prone to damage from the weight of the house above it, or the ground shifting around it. Because of this they require more maintenance. They are also much more expensive to build than a plate foundation. If you want to extend the house or make additions, it's also much harder to work on the foundation. Extending the foundation might mean simply adding Plate foundations for the newer pieces.
Sometimes you have the opportunity to build a home hill-side. But you can't build a straight foundation up on a hill, so it would need to be partially dug out and a concrete box built to prevent water and moving ground up the hill from pushing your house down. This box functions as the home's foundations, but is by itself also a cellar.
Because the front of the foundations are open to the air, it means you can use it as part of the house. It's not hidden like a cellar, but because its sides are partially hidden by the slope, it doesn't make your home look massive.
The slope house features all the benefits of a cellar, but also its drawbacks. Because it is only partially dug in, part of it is also in contact with the air and needs to be treated like the outside of any home would be.
Usually the entrance to the house is in the bottom part, unless there's a road or plateau that would allow easy access to the main house. So if you build a slope house, there is a good chance that the living areas will be inside the foundations. This means that you will need to make sure that this area is ventilated and secure, and that it is comfortable to live in.
If you manage to get the entrance on the first floor (so above the foundations) you can use the sloped cellar as a traditional cellar, albeit one with a view outside. So at the additional costs involved of building a sloped cellar, and the disadvantages it may bring, you bring a great view from the top level and light into your cellar spaces.
If you have the amazing opportunity of building a lake house, you will need stilts. These are essentially piers made of long wooden poles that are dug deep into the lake bed and secured with concrete feet. The house is connected to these poles with anchor feet, which allow the house to slightly move to prevent it from being affected by too much of the pole movements.
This has all advantages and disadvantages of the pier foundation, but you also need to contend with building inside a watery site. In many cases this means building a temporary dam to keep the water away while your home's foundation is placed. That can be very expensive.
Additionally, moisture and weathering is a constant concern. Water and aquatic life can do tremendous damage to wood over time, even if it's treated. So this house requires regular upkeep and now and then some of its foundations may need fortifying or even replacement.
Power and plumbing need to come from straight out of the house, as there's no ground for it to go through. This means some form of transition pipe from the house to the side of the lakebed, and that can be somewhat unsightly.
But in return for all this, you get an amazing view and the opportunity of being free from the ground entirely. If you love the water and want to be able to do some fishing from your patio, your lakehouse will need to have stilts for a foundation.
As you can see, the circumstances of your plot will determine what foundation works best for you. If you don't want a hill blocking your view, build your house up against it. If your soil is rock-hard you may be best off with piers. If you want to have plenty of space but don't want your small home to look stocky, opt for a cellar.