For the majority of novice builders, this is a very difficult question. Recently, it worries people more often than the dilemma: plate or tape. Why? Obviously, due to the significant price difference: a slab is five times more expensive than a pile foundation on average. In any case (and construction is no exception), a person wants to pay less, and if you already make a choice in favor of a more expensive option, then understand that it was inevitable. So here is the main question – which of the two types of foundation should be preferred? – we will answer in this article.
And is there a choice?
There are several situations when there is simply no choice between a slab foundation and a pile foundation, and there cannot be. Given their design features. For example, all houses made of brick, concrete and blocks, due to the large weight of the building, require a more reliable and strong foundation than piles. In such cases, it is usually about using a slab foundation (monolithic or block), thinking about the thickness of the slab, the level of its depth, about replacing it with a lighter “tape” or, on the contrary, strengthening it with the help of piles and grid. The specific parameters of the slab depending on the soil and the number of floors of the house.
There is also the opposite situation, when the only option is the pile foundation. We are talking about construction on wetlands and on soils with low bearing capacity. The slab should not be built in such places, but piles installed at a certain depth (from 3 to 7 m) rest on solid ground and create a reliable foundation for a monolithic reinforced concrete structure, called a grid, which evenly distributes the load on the piles. In this case, accurate design calculations are especially important.
When you are going to build a wooden or framed house, here is the opportunity to build a slab or use piles – the choice is yours.
Plate: pros and cons
A monolithic reinforced concrete slab is the most popular type of foundation today. It is willingly offered by construction siding companies, it is included in the working documentation of finished projects. Why?
The tile foundation is a universal solution for the vast majority of cases, it is suitable for many soils in any region of our country. The thickness of the plate can be different – it depends on specific conditions. When creating typical projects, we lay a slab 350 mm thick regardless of the material of the walls. In some cases, this margin of safety will be excessive, but this way we can guarantee the safety of almost any house built according to our project. The slab is the strongest and most reliable foundation of the building: due to the uniform distribution of the load, it can withstand the large weight of the structure and is less prone to destruction, in particular corrosion, than piles. Such a foundation can stand for 200 years, provided it is properly installed. In addition, the slab has a minimal shrinkage factor, unlike other types of foundations. And finally, its manufacturability conquers: it is convenient to lay the slab in the project (I am sure, many designers appreciated this back in their student days) and it is no less easy to build, as evidenced by the popularity of such a base among construction companies.
The advantages of a slab foundation are obvious. No less than this novices in construction are impressed by the costs of earthwork and concrete work. It is believed that the cost of the foundation for a stone house makes up a third of the entire construction budget. Knowing the specifics of your site (soil research) and consulting a design specialist will help you save here. Perhaps, in your case, the thickness of the plate may be less and deepening is not required, or even you can do without a strip foundation.
A house on chicken legs?
The foundation of piles is very difficult to fit into the system of human ideas about the foundation of a house – a frame structure on piles is popularly called a “cardboard house on chicken legs”. After all, we build for centuries (so that grandchildren and great-grandchildren will have it), with a huge safety margin (for just in case ). And it is clear to everyone that concrete is stronger and more durable than even the best steel. So, the choice is obvious? But no.
Economic conditions change the national mentality, forcing at times to solve problems with housing here and now, for themselves, and not for future generations.
So, what are the possibilities of a pile foundation for wooden houses? First, it can be erected on any soil (except rocky); secondly, construction does not depend on the season; thirdly, it happens very quickly (in one or two days); fourth, inexpensive. Additional savings can be provided by replacing the concrete grate with metal or wooden strapping. And remember, when construction work and facade finishing are completed, no one will ever guess on which foundation your wooden house stands.