Step-by-step instructions for building a pile-strip foundation with your own hands

Constructing a pile-strip foundation can be a sensible option for building a sturdy and steady base for a variety of structures, including additions and tiny houses. This kind of foundation combines the affordability of strip foundations with the stability of concrete piles. You can save labor costs and ensure that the pile-strip foundation meets your building needs by building it yourself with a methodical approach.

Examine the soil conditions on your construction site first. The kind of soil greatly influences the concrete piles’ depth and spacing. In order to determine the soil’s capacity to support loads and identify any potential problems, such as expansive soils, a soil test is usually advised. Long-term stability is ensured by using this information to inform the design and placement of your foundation.

Next, get your foundation’s layout ready. As per the recommendations of the soil engineer and your building plans, mark out the perimeter and the locations of each pile. Make sure the arrangement is exact so that connecting beams or strips and concrete piles can be placed precisely.

Dig the pile holes down to the designated depth—typically, this is below the frost line to avoid movement from freezing and thawing. The holes’ diameters should be large enough to comfortably fit the concrete piles and leave room for reinforcement, if needed. Make sure the holes are level and firm at the bottom and take care to clear any debris.

Start inserting the concrete piles after the holes are ready. In order to ensure that every pile reaches the required depth and forms a solid base, concrete must be poured into each hole surrounding any reinforcement cages, if any. To ensure consistency and stability throughout all piles, use a level to verify vertical alignment while pouring.

Differences between SLF and other bases

A single monolithic structure that concurrently combines piles and a grillage is what distinguishes a SLF foundation from other kinds of pile foundations.

This foundation has the major benefit of only requiring one pour of liquid concrete; no separate work is required for the installation of the support perimeter made of various materials or the construction of monolithic pillars.

Unlike other types of foundations, where reinforced concrete piles respond to loads differently than a grillage made of rolled metal or wooden beams, a single monolithic SLF functions as a single system.

This structural feature gives the foundation a higher bearing capacity and excellent dependability. In monolithic concrete, the load is distributed evenly over the whole volume of the foundation by a single reinforcement frame.

One characteristic of the SLF is that it’s designed for building homes on loose, weak soils, which can be found in both lowlands and on slopes.

Because of the varying pile heights on a large slope, the building on the grillage appears to float in midair, "ignoring" the intricate topography.

The inability to build basements or a basement floor is the sole and major drawback of this kind of foundation.

Preparing for work

The time leading up to the construction of the foundation consists of:

1. SLF calculation.
2. Materials.
3. Tools.

Calculation

Gather the loads from the house acting on the supporting structures before you start calculating the foundation. To compute the ideal bearing area, the maximum ground pressure must be ascertained.

Add up the weight:

• all designs,
• technological equipment,
• pipelines,
• furniture and everything that can be in the house at the same time, including people.

Additionally considered is the snow load on the roof, whose value is derived from SNiP.

Accurately identifying the properties of the soil is essential. The construction site’s vertical photography helps identify them. These documents are available from the land management and architecture departments in your community. They have to show the elevation of the soil bearing layer, the level of groundwater, and the depth at which freezing occurs.

To conduct survey work, get in touch with the nearby geological exploration service if obtaining a copy of the vertical survey is not feasible. Soil samples extracted from drilled boreholes can be tested to ascertain the properties of the soil.

The length of the pile is computed by examining the data from the soil foundation. It is made up of the above-ground portion’s height and the foundation’s depth. The point support’s longitudinal size needs to be such that its heel is submerged in the load-bearing soil layer by at least 300 mm, above groundwater, and below the freezing zone.

By dividing the supporting area by the heel size of one pile, the ideal number of piles can be found. Additionally, the area is computed based on the generally acknowledged specific load from the house, which ought to be lower than the resistance of the soil layer that bears the load. Soil resistance value is derived from vertical survey.

Generally speaking, determining the grillage involves using a conditional cross-section of the tape, with a height of at least 400 mm (this is because longitudinal reinforcement bars are best placed at a minimum distance of 30 to 50 mm from the upper and lower outer surface of the tape). The monolithic strip’s width is determined by adding 30 mm to each side from the wall’s thickness.

Underneath the rods are wooden or plastic supports that help maintain the ideal distance between the lower reinforcement chord and the bottom of the grillage formwork. This ensures that a layer of concrete protects the metal from corrosion.

Materials

The materials needed to build the foundation are ready before work begins. In the event that there isn’t any flowing water, a container equipped with the required water supply is placed at the location.

The site will receive the following deliveries:

Shells made of asbestos-cement, metal, or plastic sewer pipes are assembled to create piles. You must have plenty of plastic film on hand in order to cover the formwork’s internal surfaces.

Tools

You must compile the following list, using which you must get ready the following instruments:

1. Laser level.
2. Garden auger.
3. Shovels and bayonet shovels.
4. Cord and benchmarks (wooden pegs or pieces of reinforcement).
5. Wheelbarrow.
6. Saw, hacksaw, hammer, trowels, stapler.
7. Mortar mixer.

Technology for self-construction of a strip foundation on piles with step-by-step instructions

It should be made clear right away that this instruction is advisory in nature and is not intended to serve as a precise guide for implementing the points. The developer modifies it according to local construction conditions in each unique instance.

Experts advise taking the actions listed below:

• determining the distance between piles;
• marking and excavation work;
• installation of piles;
• production and installation of tape formwork;
• reinforcement of piles and grillage;
• waterproofing and ventilation of the foundation;
• pouring the foundation with concrete;
• thermal insulation.

Determining the distance between supports

Notwithstanding the approximate quantity of piles, the standards for the construction of light buildings dictate that the spacing between them be between 1500 and 2000 mm.

When the grillage is above ground, there must be a minimum of 1.5 meters between the piles. This is elucidated by the requirement to reduce the load on the beam (grillage span).

Depending on where the monolithic tape is located in space, pile installation sites are spaced 1.5 to 2 meters apart after the corner supports are first indicated on the foundation plan.

When installing a monolithic slab for a boiler or other large equipment, supports are positioned beneath it every 1000 mm according to the construction plan.

Marking and excavation work

The following order is followed when performing the work:

1. Before starting work, debris, vegetation and fertile soil are removed from the construction site.
2. The marking of pile supports and shallow strip foundations starts from one corner of the foundation plan and is carried out on adjacent sides. The route is punched with a double cord, which marks the width of the grillage. The centers of future wells are fixed with wooden pegs.
3. The SLF plan can be one or several rectangles. The correctness of their construction is checked by the equality of the diagonals between opposite corners using a cord.
4. According to the markings, trenches are dug to the design mark, taking into account the thickness of the crushed stone and sand cushion.
5. With a garden drill, holes are drilled in the ground to the design depth.
6. The bottom of the trenches and wells is filled with crushed stone and sand with a thickness of each layer of 100 – 150 mm, followed by ramming.
7. With a laser level and a rail, the equality of the marks of the bottom of the trenches and wells is checked.

Installation of piles

Professional builders advise that the wells be made slightly wider than the pile shells’ outer diameter. This is required to modify the point supports’ verticality.

If the hole in the ground is made with a slight deviation from vertical, the installed pipe can be tilted or moved. The pile is fastened in place by fastening timber pieces to it.

Production and installation of tape formwork

The formwork of an above-ground grillage and a shallow tape differ significantly.

The difference is that formwork in the first scenario is an open box with a sturdy bottom, while plank boards are only positioned on the sides of the trenches.

If sidewalls made of boards that are only 25 to 30 mm thick are sufficient, wood that is at least 50 mm thick is used to construct the box’s bottom. In certain instances, extra supports are erected in between the piles to support the ground grillage formwork.

Plastic film is placed on the bottom of the trenches and the inner surface of the shield fences to stop liquid concrete from seeping through the spaces between the boards. Using a stapler or tiny nails, it is fastened to the boards. The film aids in giving the monolithic strip a smooth surface.

The panels are strengthened with wooden spacers and supports. Panels are secured with boards. A screwdriver is used to screw the formwork’s components together into a single structure if it is made of construction plywood.

Holes with a diameter equal to the pipe opening are cut in the locations where the grillage is supposed to rest on the piles.

Reinforcement

They reinforce them after installing the grillage formwork and pile shells. The reinforcement is lowered into the pipes; it may consist of one or more vertical rods connected by knitting wire that have smooth sections Ø 6 mm and a periodic profile of ø 8–10 mm.

Up to a height that allows them to connect to the grillage reinforcement cage, the vertical reinforcement rods are carried. The formwork is filled with segments of the reinforcement cage, which are connected by wire and releases of pile reinforcement.

Waterproofing and ventilation

Maintaining the integrity of the monolith requires careful attention to the protection of reinforced concrete structures from moisture. After the formwork is removed, the pile-strip foundation is waterproofed.

Hot bitumen mastic or liquid rubber spray are used to fuse rolled material, also known as roofing material, to the grillage’s sides.

Waterproofing is not necessary for piles because their outer layer is composed of plastic pipes or asbestos-cement. Their material is completely impervious to moisture because it is hydrophobic.

The underground area’s ventilation, which is controlled by a shallow monolithic tape barrier, is crucial in preventing air stagnation and promoting the following:

• accumulations of harmful microorganisms,
• mold,
• fungi,
• high humidity levels.

The foundation monolith has vents installed in order to prevent these undesirable phenomena.

Prior to pouring concrete, products are positioned within the formwork. Polyethylene pipe scraps are used to make them. They emerge from the tape’s holes, which are situated on opposing sides of the grillage’s perimeter. Pipes are typically installed in 3–4 meter increments.

How to fill correctly?

In a mortar mixer, concrete mortar is made while paying attention to the ratios of cement, crushed stone, and sand.

For foundations, concrete grade 300 is utilized. You will need to use cement M 400–500 to prepare it. This prerequisite needs to be satisfied.

Water is added to the mixer little by little as the ingredients are mixed, until a thick, homogenous solution is achieved. Wheelbarrows are used to transport the solution to the pouring site.

Pile pipes are first poured using a tamper that works layer by layer. Use an electric vibrator if at all possible. After that, a vibrator or tamper made of readily available material is used to pour concrete into the grillage formwork.

A film is applied to the concrete surface to prevent it from drying out in the sun and from becoming soggy after rain. The film is removed and the formwork is disassembled after 30 days.

Thermal insulation

By insulating the blind area surrounding the house, shallow SLF is shielded from cold penetration. This is accomplished by either covering the sinuses between the expanded polystyrene sheets or filling them with expanded clay between the plinth and the foundation in front of the blind area. The first floor’s floors are insulated when a pile grillage is built at a height.

This section contains a wealth of pertinent and useful information regarding the construction of strip-pile foundations.

This post will walk you through the process of building a pile-strip foundation, which is an affordable and useful option for a variety of building projects. From planning and site preparation to the detailed procedures of installing piles and joining them with strips of reinforced concrete, we cover it all. Whether you’re renovating an old building or building a new one, this guide offers crucial knowledge and useful advice to help you lay a strong foundation for your project.

Video on the topic of the article

Phases of a pile-strip foundation’s self-production are shown in the video:

Step 1: Site Preparation	Clear the area where the foundation will be built. Mark out the dimensions for the foundation trenches.
Step 2: Excavation	Dig trenches to the required depth and width according to your local building codes and soil conditions.
Step 3: Installing Pile Footings	Place concrete piles at specified intervals along the trench. En Backfilling	Backfill around the completed foundation to stabilize the soil and prevent settling.

Because it offers a sturdy foundation for your construction needs, building a pile-strip foundation can be a satisfying do-it-yourself project. These detailed instructions will help you guarantee a solid foundation for your building.

First, determine the location of the foundation by surveying and delineating it. This is an important step because it sets the foundation’s dimensions and alignment. Plows and string lines can be used to precisely mark the perimeter.

Next, dig the strip footing trenches in accordance with your design requirements. Make sure the trenches are excavated to the necessary width and depth, taking into consideration any extra needs like drainage or insulation.

After the trenches are dug out, place the concrete piles along the trenches at predetermined intervals. The foundation is stabilized and supported vertically by these piles. Before pouring the concrete, make sure each pile is positioned and aligned correctly.

It’s time to build the concrete strip footing that will join and support the concrete piles after they have dried. As you carefully pour the concrete mixture into the trenches, making sure it reaches the desired thickness and level, set up the formwork for the strip footing.

Give the concrete enough time to cure and strengthen once the strip footings are in place. For your foundation to remain stable and long-lasting, this curing time is crucial.

In order to prevent settling, backfill the excavated trenches and compact the soil surrounding the foundation after the concrete has completely cured. Your pile-strip foundation is now complete and prepared to support the upcoming stages of your building project.

It takes careful planning, exact execution, and adherence to local building codes and regulations to build a pile-strip foundation by hand. You can create a strong foundation that offers stability and longevity for your building projects by carefully following these steps.