What Are The Types of Basement Protection
– What is a foundation?
– Why protect the basement?
– Selection criteria for basement protection
– Choosing a basement protection
– Price of a basement protection
Basement protection is an essential part of the construction process, which, if neglected, can lead to many accidents and high repair costs.
What is a basement?
The base of construction is a masonry structure (breeze blocks, blocks…) or concrete poured in a formwork on which a construction will be built. Totally or partially buried, a basement is in contact with the ground by at least its base or several of its faces.
The constraints of the ring beam are multiple: it endures the vertical loads exerted by the weight of the building, and it must undergo the pressure of the earth which surrounds it while protecting the base of the construction from moisture, roots, and insects.
Why protect the basement?
In any construction, and even more so if part of it is buried (cellar, crawl space, garage in the basement…), the insulation between the backfill earth and the walls is essential, even though concrete walls are less permeable to capillary rise, water exchange, salts and minerals than masonry walls.
Criteria for selecting a basement protection
You must select basement protection according to two main criteria:
The nature of the ground
In particular, its hydric characteristics may require that peripheral drainage be carried out before installing base protection:
– In permeable soil (both the soil itself and the excavation backfill): generally, a granular or sandy soil in which rainwater infiltrates without stagnating, peripheral drainage is not necessary, and only the base protection is sufficient.
– In clayey or silty soils that are pretty impermeable: the water may stagnate without penetrating deep into the soil, which requires drainage around the base protection.
The destination of the partially buried parts
It is declined into 3 categories:
1. The walls of the premises cannot support any trace of humidity (living quarters, offices, game rooms, or movie theatres…): they are classified in the first category, which requires protection of the basement, ensuring waterproofness.
2. The walls of non-habitable premises can support some traces of moisture (boiler room, cellar, garage …): they are placed in the second category, which requires only protection of waterproofing (not waterproofing).
3. The walls of non-accessible parts (crawl space, earth walls) that do not require special treatment are placed in the third category (without waterproofing or sealing). However, other protections are required, particularly against termites and other insects.
Please note: when there is a risk of the water table rising on a property, especially near watercourses likely to flood, waterproofing and sealing the base is not enough. It is then necessary to build a casing.
To ensure drainage, waterproofing, and sealing according to the required levels of protection of the bedrock, the traditional materials (aggregates, geosynthetic…) have gradually given way to the use of sheets with excrescences.
Buried excrescent waterproofing sheets are thick films made of extruded high-density rot-proof polyethylene. They are interspersed with cells (on the ground side) and bubbles (on the masonry side) or vice versa, which physically isolate the basements while creating a decoupling air gap between the backfill and the construction.
Choosing a base protection
Thus, according to the role(s), the base protection will have to ensure that one will select which sheet to excrescendo among the following ones.
They mainly have a mechanical protection role in withstanding the ground pressures. It is the protective layer of the basement sufficient for permeable soils and non-habitable premises.
Protection + filtration + drainage layers
They ensure filtration and drainage thanks to an integrated geotextile on the backfill side. In contrast to the protection blankets, the cells are set on the backfill side to create a space between the blanket and the geotextile so that drainage can occur.
Protection + filtration + drainage + waterproofing sheets
They also have a PVC vapour barrier film that ensures waterproofing by allowing air to circulate, but not the water vapour and humidity that this air carries.
In addition to a protective sheet, it is never out of the question to cover the buried walls with products that provide partial waterproofing, particularly against the growth of plants. In this respect, there are two categories of products: grey cement-based and black bitumen-based.
Good to know: bedding mortars are generally industrial mortars to which an additive has been added (water repellent, waterproofing, super-plasticizer…) that cement and screed manufacturers can supply and apply.
The price of a buried base protection includes the supply and the installation of the plaster and mortar, then the alveolar sheet installed by a professional.
Please note: some prices for cellular sheeting are quoted by the ml (linear meter) in 1m, 1.5m or 2.4m widths. The m² quotes others, and still others by the roll, generally 20m long but in different widths.