Provisions and regulations
Anyone starting a construction project must ensure that the building is designed and built in line with the construction provisions and regulations and the permit granted. They must have sufficient expertise to carry out the project, taking into account the complexity of the project, and have qualified personnel at their disposal.
The building permit application must be accompanied by an account of the foundation conditions and ground conditions of the site and, where appropriate, of the health and elevation thereof, as well as of the foundation method and any other necessary measures required by them. The account must include, inter alia, a preliminary description of the ground conditions and of the foundation method. Usually, a more detailed foundation plan is drawn up only after the construction permit. The foundation method description may already be available in the building permit application.
In Espoo, the Building Control Department is the authority granting permits and requires a reliable foundation method description for buildings, excluding light-weight sheds/garages.
In the first instance, the foundation designer is responsible for the scope and quality of the geotechnical analysis. Already when purchasing a plot, it is recommended to use a qualified designer who can determine the probable foundation method even at a rough level.
The geotechnical analysis data and extracts from the soil and constructability map retrieved from the eCity service (Pohjanpoika) are not sufficient for the foundation method description. In addition to existing research data and map data, those engaging in construction projects must usually commission project-specific geotechnical analyses involving a written foundation method description. In a rocky area or on otherwise firm soil, it may be sufficient to excavate test pits to satisfy the geotechnical analysis requirement. On the basis of the test pit, the project’s designer of foundation structures must compile a foundation method description.
The design of steel piles requires, among other things, knowledge of the shear strength of clay. Vane auger is usually used to determine the shear strength of the clay layers.
City of Espoo’s building ordinance requires provision for the occurrence of radon in the design and construction of construction projects.