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Foundations and all you need to know about it!

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FOUNDATIONS

Foundation plays crucial role in building stability.

Building a house is always an exciting project, in which we involve our time, dreams, expectations and money.

The construction of a house is composed of many essential steps. In this post, we speak about the foundations of the house and their settlement. The foundation construction is part of the early steps when erecting a house.

  • Why is it important?
  • How they are defined?
  • What are the options?

Let us guide you through the foundations step!

 

THE ROLE OF FOUNDATIONS

The house foundations are settled, hidden into the ground and partially seen on the surface. They play a crucial role in the building stability, durability, and the overall construction quality.

The foundations are primordial to ensure the security and durability of a building. Some of the major roles are to support the structure weight, stabilize the building through time and keep it standing straight. The foundations are acting as a sole between the ground and the building, transferring the weight of the construction to the soil using ground and rocks mechanics, that is to say, the natural movement and actions of ground and rocks.

Therefore, the house foundations prevent land subsidence, landslides, and other distorted ground movements, capable to impact the integrity of the building and with it, its balance and steadiness.
During bad weather, such as heavy rain, flood, substantial snowfall storm, strong wind, and other inclement weather changes, which can impact the building and ground conditions, the foundations stabilize and secure the construction by preventing lateral movements, collapses, and other possible kinds of distortions.

Besides, the foundations protect the construction from water infiltration’s, moisture, damp and other detrimental kinds, which create the perfect environment for fungus and mould development, possibly causing irreversible or/and costly damages. Thanks to foundations the house is preserved from external attacks to remain a healthy and sustainable living place.
Beyond protecting the house from undermining elements and ensuring the structural integrity of the entire dwelling, the foundations also have a notable role to play in the house comfort and cosiness.

The heat loss operating from a house is not only made through the walls, windows, and roof, but also through the flooring. The foundations reinforce the insulation, in a more or less efficient manner depending on the technique used (concrete slab, strips…).
In many cases, the heat loss is decreased as the building is not in direct contact with the ground, reducing at the same time the bill.

As the foundation step starts at the very beginning of a house project and construction phase, the understanding of their role is essential to design proper ones for the project. Good foundations are simply primordial and will provide a lovely and secured home for a long time.

The durability of a house depends, among other things, on the thorough planning and construction of the foundations. Their quality is impacted by the quality of the used materials. Good quality materials, proper respect for foundation construction and of drying times, are non-negligible.

In addition to high-quality materials, the proper engineering methods and techniques have to be used to build this house support. It ensures the sustainability of the building over the years. The building specificities – the number of floors, weight, nature of the materials used, use of the building, etc. – as well as the ground composition, enlighten the best choice for foundations.

A FRAGMENT OF ETYMOLOGY
THE WORD “FOUNDATION” FINDS ITS
ORIGIN IN THE LATIN LANGUAGE. IN LATIN, THE ROOT “FUND” IS USED IN MANY WORDS LIKE “FUNDUS”: A BOTTOM/ BASE, OR “FUNDARE” WHICH MEANS “TO LAY A BOTTOM OR A BASE”. FROM THIS ROOT IS ALSO MADE THE WORD “FUNDATIO”: A FOUNDING.
LATIN INSPIRED OLD FRENCH LANGUAGE, IN WHICH CAN BE FIND THE WORD “FONDATION” (A NOUN) AND “FONDER” (A VERB). THE WORD “FOUNDATION” IS USED IN ENGLISH AROUND 1400. THE ROOT “FOUND” HERE MEANS “SET UP/ESTABLISH”.

 

THE GROUND ROLE & THE VALUE OF SOIL STUDY

The ground composition will be studied and defined during a ground study, realized by experts. This study is highly recommended and helps to answer the following question “Which foundations are the most adapted to the soil type of the construction site?”. Indeed, the soil composites, their quantity, and features influence the ground balance, impact the environment of the construction, and the construction itself. Soil study is one of the first components of the foundations step.

Many different types of ground are inventoried as they vary from a region, a country, a continent, and another. If some regions will be mainly composed of sand, not so far from them, the ground will be solid rocks. Therefore, the foundation types and features will also vary according to the ground composition.
Among the ground types, very often are encountered clayey, sandy, and rocky soils.

 

Foundations on sandy ground

The sandy ground is the most convenient to build foundations on, as it is unlikely to move and is showing dampening properties. The best situation occurs when the ground is fully covered with a homogeneous amount of sandy soil.

Unfortunately, most of the sandy grounds are mixed and present an irregular amount of rocks, clay, and sand here and there on the land. The foundations installed on this type of soil are usually made a bit larger than the construction dimensions, in order to ensure sufficient upkeep.

 

Foundations on rocky soil

The rocky soil can be considered as “neutral”, as it is not defined as a good or a bad ground for building. It is a solid ground, which can cost a little bit of money to work with, as specific machines are often needed to do the job.

 

Foundations on clayey soil

The clayey soil is the most constraining one: the water infiltration affects the clay and turns it into an unsteady ground. In contact with water, the clay is reacting like a sponge: it grabs the drops and inflates.

The ground study is, for this type of soil, impossible to avoid, as the foundations should be set up under the clay layer, reaching a more stable ground.

The daily ground movement is not noticeable but the consequences of these changes are, however, observed. One of the most common distortions, appearing on buildings and often link to the ground changes, is the crack.

The crack is a more or less deep and large split, which can appear on the interior walls, exterior facades, foundation sides, or even ground flooring and marking an ungraceful line onto the building structure. The cracks are the testimony of the ground movements and often inappropriate foundations. Therefore, the repairing products find in shops are inefficient, and these damages can be costly when they can be fixed by professionals.
Several factors can serve as an explanation for the apparition of these bothers.

 

Soil three main elements

The soil is composed of three main elements: liquid, gas, and solid. The modification of one of these three elements alters the balance of the soil and, as a consequence, the balance between the house and foundations.

A modification can be caused by water, as for a clayey soil: the soil inflates when it is waterlogged and recants when the water evaporates. On the contrary, the water infiltrating sandy or rocky soils will move the small particles down as these types of grounds let the drops pass by. This phenomenon will cause the land to lower.

Ground modifications also happen during drought or can be caused by human activities (nearby constructions, traffic) or nature (when tree roots navigate underground and move the ground upper to free space, for instance).

These are the reasons why foundations are primordial for any type of construction and should be carefully studied and designed to be efficient.

The ground study, in addition to determining the soil quality and composition, also helps to establish the depth for which the foundations will be adequate and optimal. The depth is imperatively set up by the “good ground”.

 

SCIENCE FOR THE EARTH

Geo-technical engineering, a branch of civil engineering, is the analysis and understanding of natural movements of ground and rocks. It is the science related to soil and rock mechanics, that is used to analyse the natural forces and actions of the grounds and to apply them to human activity.

Civil engineering was created between the 18th and 20th centuries, and according to most members of the scientific community, it is also during this period that the sector extended. In 1936, the ISSMGE, International

Society for Soil Mechanics and Geo-technical Engineering is founded between scientists of 20 different countries. Through the years, the organization was growing bigger and evolving fast, just as the field itself.

The study of soil and rock mechanics is fundamental to investigate and observe the undergrounds, and Geo-technical Engineering allows gathering basic and crucial data for any activities directly dealing with sub-soils, water, and ground stability. These data are collected to evaluate, design, and build infrastructures and buildings.

Foundation engineering is one of the requisite activity branches of geo-technical engineering. Thanks to the field, it is possible to design foundations holding up men and natural loads, vertical and lateral pressure, weight structures of any construction, from cabins to skyscrapers, including bridges and monuments. The study consists of drilling into the soil and rocks to collect samples, sent afterwards for analysis.

 

Soil properties

The analysis helps to determine the soil properties as it is a very complex and variable element. Among others, the grain size, cementation, strength, and behavior are analysed during the test. Once the soil type is determined, geo-technical engineers can start the design, taking into account the soil effect on foundations, as well as the foundations’ impact on the environment.

The risks of earthquake, landslides possibility and land collapse, soil liquefaction, are, of course, addressed.

Therefore, technical and geo-technical engineering helps to attain the best level of sustainability and durability of a building. The field is always evolving, integrating more durable and sophisticated techniques, able to answer and solve complex building and construction design challenges.

One example of constructions built before the development of geo-technical engineering and studies of the ground is the “Pisa Tower” (built during the 12th century in Pisa). As the ground was too soft and foundations not adapted, the tower started to bend on the side over time.

 

LOOKING FOR THE “GOOD GROUND”

The so-called “good ground” is the soil that lays under the unstable first layers of soil. It usually has a darker colour. In certain regions, the good soil is the one never freezing. When freezing, the water is transformed into ice that occupies more volume than water itself and leads the first layer of soil to swelling.

When the land is prepared to receive the foundations, these visual differences – of texture and colour – indicate that the “good ground” has been reached. It is this ground which will support the weight of the house and the reason why the foundations are settled underground, under the first layer of soil.

 

WHAT ABOUT THE WEIGHT?

There are two categories of weights to take into account when speaking about house construction: the dead and live loads.

The dead loads are permanent forces acting with constant action on the foundations and ground. They correspond to the weight of the structure, that is to say, the weight of all the materials used to build the house. This weight will remain unchanged. The live loads, in opposition to the dead loads, can vary. They are the total sum of all the temporary or intermittent weights.

The live loads include human occupancy, furniture, daily items, etc… Therefore the loads vary over time, and are different from one construction to another, depending on the use of the construction (hotel, offices, flats, individual houses, etc.)

In addition to the live and dead loads, the foundations should be also designed taking into account other factors, such as the weather, site location, earthquake forces, earth pressure, (counterbalancing the construction weight), thermal forces, ice thrust, shrinkage and other vertical and horizontal stresses.

 

FROM DESIGN TO APPLICATION

The construction of the house foundations can start after the soil study has been made and the company in charge of the foundations has established the best technical solutions for the building and environment, taking into account all the aspects of the house – loads, design, material weight – the ground – soil composition, mechanics – and location – weather changes, possible natural disasters, vegetation on the land…

The first step is the leveling work. This step is important to prepare the land before starting the foundations settlement. It allows also to delimit the ground accordingly to the project, secure the construction site, and to anticipate the future location of water pipes and electricity installations.

Indeed, it is at this early stage that the electric system, pipes and drainage nets are thought to be linked to the city network.

When the leveling work is completed, the foundations can be settled.

 

Basement

The foundations can include a basement (with or without windows, and which can become a new living room or simply a storage space), or a crawl space. A scrawl space is a space left between the flooring of the house and the ground. It is useful as it enables air circulation (can also be equipped with the ventilation system to improve air circulation), makes it easier to access pipes in case of problems and plays a role in the good insulation of the building. Before choosing this option, be aware that if no care is taken, the scrawl space can also harbor humidity and moisture and cause inconveniences such as mold and damp.

On the crawl space top and foundations can be installed the flooring, base of the building and construction. For instance, the flooring can built as follow: by beams, spaced and standing on the foundations, between the beams are placed hollow-core slabs, made of concrete, terracotta, polystyrene, or even chipboard. Depending on the project and analysis, the foundations sometimes have to be reinforced with an iron framework.

 

THE COST OF FOUNDATIONS

When building a house, one of the main limiting elements is the budget. To be well prepared for the construction of a house, in terms of work as well as spending’s, it is essential to list all the components of the final price.

The foundation is one of them.

The price of the foundation will vary according to the materials, the depth and surface area to cover. Thus, the foundation cost can differ from a one-storey house or a two-storey dwelling with the same number of meter squares, or for the same project but with different wall materials for instance. The cost is also depending on the foundation types and materials. If different types of foundations are possible for a type of land, it is important to go through the advantages and inconveniences of all options before making the final decision.

The foundations in a house project should represent an investment, just as a house itself, as their are one essential component of the construction and will insure the safety, durability, sustainability and play a role in the quality of the house in time.

 

Choice of foundations

The choice of foundations should not be only directed by money. If it can be tempting, be aware that the issues caused by or as a consequence of inappropriate foundations to the construction are generally costly and difficult to fix, if not impossible to repair.

To establish a price corresponding to the project, the building company uses the engineering study of soil and the architect foundation plans. The best way to have a accurate idea of the cost of the foundations is to require quotations from different companies, expert in the field.

 

THE IMPACT OF MODERN ENVIRONMENTAL CHALLENGES

The environmental questions about the impact and role of human activities – on landscapes, fauna and flora, nature disruptions, climate change or natural resource impoverishment, and CO2 release – are animating many debates nowadays and are impacting every sectors, which are expected to answer with sub-options and sustainable alternatives.

The construction field is also involved in these transformations and hold a crucial role in what will be the materials of tomorrow and the next generations of environmentally-friendly buildings.

Until now, many constructions were designed and built with iron, steel, concrete, and other materials privileged for their features such as resistance, fast drying process, durability or anti-rust, fire-resistant, waterproof, and mould resistant characteristics. These materials are also able to respond to architectural complex design and engineering requirements of a building (size, height, weight…).

The challenges of the construction industry implies among other things innovation, redesign and transformation.
Improvements have been made already and if not yet completely transformed, the field is taking initiatives in the good direction to reach this goal.

 

Environmentally friendly alternatives

For instance, concrete components have been replaced by more environmentally friendly alternatives.

Speaking about foundations, they can be the result of an association of concrete and wood: the flooring of the foundations can be made in wood and sets on concrete pillars.

For several years, new tendencies are developed on the market such as wooden pillars or screw piles. More respectful of the environment than more traditional methods. They also add a design touch and are considered as alternatives to more common foundations, when their use is possible. Indeed, the foundation types do not only depend on the visual or personal values, the ground and construction features also play major roles.

Innovations are not only visible in terms of materials but also directly during the production steps. Companies are now choosing more ecological ways to produce and do not hesitate to invest and improve each steps of the supply chain to better respond to social and environmental challenges. These values are translated by actions such as the collect, reduction or suppression of production waste, the reuse of production waste, the use of renewable energy, the implementation of strategic management or responsible sourcing.

 

THE FOUNDATIONS OF WOODEN HOUSES

The wooden houses do not require a specific type of foundations and can be built on all the types used by other kinds of houses. Therefore, the wooden houses or log houses can stand on full concrete foundations, concrete foundations with wooden flooring, prefabricated beams, foundations more or less deep… depending on the ground and building features (weight and size).

The wooden houses have the advantage to be lighter than brick and mortar constructions; therefore, the foundation type is sometimes less expensive and more diversified than other traditional buildings. To stick to an environmentally sound approach, the house can be settled on screw piles, for instance. More information about planning your new home can be read here!

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