Checklist for Building a Foundation for a Wooden House

Geological and Geodetic Survey

Before starting construction of the foundation, it is important to carry out thorough geological and geodetic surveys of the plot.

Geological survey

A geological survey helps assess the physical and mechanical properties of the soil, the presence of groundwater and possible risks.

• Purpose: Determining the bearing capacity of the soil, its heaving, density and other characteristics.
• Procedures: Carrying out drilling operations to take soil samples; laboratory analysis of the soil; identifying groundwater depth and its seasonal changes.
• Legal basis: In Italy such work is regulated by D.Lgs. 152/2006 (Codice dell'Ambiente), which defines the procedure for research for environmental protection purposes.

Geodetic survey

A geodetic survey is carried out to determine the topography of the plot and identify potential problems related to the relief.

• Purpose: Ensuring the accuracy of foundation planning and optimal placement of the house on the plot.
• Procedures: Preparation of a topographical plan of the plot; identifying slopes, irregularities and elevation points; analysis of possible soil settlement.
• Legal basis: Requirements for geodetic work are defined by standards UNI 10736 and recommendations of regional administrations.

To carry out surveys, involve licensed companies or specialists with experience in Italy. Their conclusions will form the basis for correct foundation design.

Foundation Design

Depth of the foundation is determined by the type of soil, groundwater level and climatic conditions. In regions with seasonal freezing (for example, the Alps) the depth should be below the frost line, as prescribed by standard UNI EN 1997-1. In warm regions, shallow foundations are allowed, especially for light structures. The minimum depth is usually 50–60 cm but may be greater depending on the type of soil and structure.

Foundation dimensions are designed to distribute the load evenly. For example, a strip foundation for a wooden house usually has a width from 40 to 50 cm, while for heavier structures or weak soils it is necessary to increase the width and depth. These parameters are strictly regulated by NTC 2018 standards to avoid settlement or destruction of the structure.

Foundation reinforcement is carried out to prevent cracks and increase its strength. The number of reinforcement bars and their diameter are calculated based on loads and seismic risks. For regions with high seismic risk, such as Sicily or Calabria, reinforcement design must comply with standard UNI EN 1998-1.

Drainage and waterproofing are mandatory to protect the foundation from moisture and groundwater. Laying drainage pipes along the perimeter and using waterproofing membranes that comply with standard UNI EN 13967 help avoid damage from moisture and mold. This is especially important in regions with high rainfall.

Seismic loads must be taken into account in seismically hazardous zones of Italy. For such plots, it is recommended to use anti-seismic structures, including reinforced monolithic slabs or foundation blocks with damping elements. Design is carried out in strict accordance with NTC 2018 and UNI EN 1998-1.

Thermal insulation of the foundation is relevant in regions with a cold climate. The use of thermal insulation boards made of polystyrene foam or extruded polystyrene helps to avoid heat loss and condensation.

Foundation design in Italy is carried out taking into account all safety standards, including approval of the project by a licensed engineer and supervisory authorities. This guarantees the durability of the structure, compliance with local standards and minimization of operating risks.

Formwork Installation

Preparation of materials. Boards, plywood or metal structures are usually used for formwork. It is important that the materials are strong and withstand the pressure of concrete.

Formwork installation.

• Placement. Formwork is installed along the foundation boundaries, exactly corresponding to the design dimensions.
• Fixing. The structure is fixed with supports, posts and braces to prevent displacement during concrete pouring.

Checking geometry. Before pouring, it is necessary to check the horizontal and vertical alignment of the formwork using a spirit level. This ensures a level foundation surface.

Waterproofing of the inner surface. To prevent concrete adhesion and simplify dismantling, the inner side of the formwork is treated with oil or covered with film.

Compliance with standards. Formwork installation must comply with Italian standards such as UNI EN 13670, which regulate requirements for concrete structures.

Formwork ensures not only the exact dimensions of the foundation but also its strength, forming the base for further construction work.

Reinforcement of the Foundation

Purpose of reinforcement. Reinforcement is necessary so that the foundation can withstand loads and does not crack under external forces such as compressive, tensile or bending loads. Reinforcement acts as reinforcement for concrete, which works well in compression but poorly in tension and bending.

Types of reinforcement.

• Reinforcing mesh is used for reinforcing strip and monolithic foundations. The mesh consists of wire with a diameter of 6–12 mm, welded in a grid with 100×100 mm or 150×150 mm cells.
• Straight reinforcing bars are usually used to reinforce separate elements such as columns or piles.
• Reinforcing cages are structures made of reinforcement bars tied together with wire. The cage is placed in the formwork before concrete pouring and serves as the basis for foundation stability.

Reinforcement process.

• Placement of reinforcement. Reinforcement must be placed inside the formwork so as to ensure uniform load distribution. It is important that reinforcement is not located too close to the edges of the foundation to avoid corrosion. According to Italian standards (for example, NTC 2018), the minimum distance from reinforcement to the outer surface of concrete must be at least 3 cm.
• Tying and fixing. All reinforcement elements are tied together with wire or special clamps, which prevents their displacement during concrete pouring. In some cases, special plastic or metal spacers are used to fix bars at the required height.

Materials for reinforcement. In Italy, steel bars that must comply with standards UNI 10020 and UNI EN 1992-1-1 are used for foundation reinforcement. Galvanized or polymer-coated reinforcement is often used for corrosion protection.

Quality control. It is very important to monitor the quality of reinforcement in order to avoid the use of low-quality materials that can lead to reduced foundation strength. Reinforcement must be free of defects such as corrosion or cracks. Inspection must be carried out in accordance with Italian building regulations.

Reinforcement of the foundation is an important stage that directly affects the durability and reliability of the entire structure. Proper reinforcement allows the foundation to withstand various loads, preventing concrete destruction under external factors.

Technical Control

Soil quality control. At the stage of geological and geodetic surveys, it is important to control soil quality. Geological surveys determine the characteristics of the soil, its bearing capacity and stability. This is especially important for choosing the type of foundation (strip, column or pile).

Control of site preparation. After the plot has been prepared and earthworks carried out, it is necessary to control the depth and width of the excavation. Make sure that all dimensions correspond to the project, and that the sand and crushed stone cushion has been laid correctly to ensure foundation stability.

Control of formwork installation. When installing formwork, it is necessary to check its stability and compliance with design data. Errors at this stage can lead to foundation deformation. The accuracy of reinforcement placement inside the formwork before concrete pouring is also checked.

Control of concrete quality. Concrete used for foundation pouring must meet strength and durability standards. It is important to control not only its composition but also the method of pouring to avoid air pockets and other defects. At this stage, concrete strength tests are carried out to guarantee its compliance with standards such as UNI EN 206 (concrete standard).

Control of reinforcement. During reinforcement of the foundation, it is necessary to check the quality and placement of reinforcement. Reinforcement must be correctly placed in accordance with the project, and its diameter and quantity must correspond to the calculated data. This guarantees the strength and stability of the foundation.

Control of utility quality. When laying water supply, sewerage and electrical cables at the foundation construction stage, it is necessary to ensure that all technical standards are observed. The tightness of connections and the correct laying of pipes and cables are checked, as well as their compliance with the project and standards such as UNI EN 12056-2 for sewerage and CEI 11-1 for electrical cables.

Control of work completion. After completion of the main work on foundation construction, final control must be carried out. This includes checking that all structural elements correspond to the project and checking the quality of all materials. This is confirmed by acceptance certificates, which must be signed by the engineer and builder.

Documentation and reports. All results of technical control must be documented, including photographs, test reports and expert opinions. This is necessary for further analysis and reporting.

It is important to remember that foundation construction is one of the most responsible stages in building a house. The quality of this stage determines not only the durability and stability of the entire building but also the safety of its operation. An incorrectly designed or executed foundation can lead to deformations and even destruction of the structure, which makes its reliability and compliance with regulatory requirements key factors in the success of the entire construction project.