Replacing The Foundation: How To Replace A Block Base Under An Old Wooden House With Screw Piles With A Building Uplift, The Option Of Converting A Pile Base To A Strip Base

2024 Author: Beatrice Philips | [email protected]. Last modified: 2024-01-18 12:09

Over time, any foundation can be damaged or completely destroyed. Deformation of the base leads to many undesirable consequences: distortion of the house, jamming of windows and doors, the appearance of cracks in the material. Replacement, restoration and strengthening of the foundation under a wooden house helps to significantly extend the service life of the structure, as well as to avoid the listed negative consequences.

We recommend:

Any work with the foundation from the company GLAV-SVAI

Site: glav-svai.ru

Free calls within Russia: 8 (800) 70-70-988

Base types

Regardless of what type of foundation for a wooden house will be chosen, it must fully cope with the following functions:

• with all loads that are associated with seasonal soil movement, for example, soil subsidence;
• it must maintain stability and not change its horizontal position throughout the entire period of construction and operation of the building;
• it must guarantee the waterproofing of the structure during floods, as well as protect the materials from the effects of groundwater.

The characteristics of the foundation are also directly influenced by such factors as:

• depth of seasonal freezing and occurrence of soil layers;
• ground water level;
• the average height of the spring flood at the site.

Depending on the material, the types of bases are stone (rubble, brick, block), as well as cast reinforced concrete and pile (on asbestos-cement or metal pipes).

By its design, the base can be columnar, tape or pile.

The features are as follows:

• Strip foundation is considered the most reliable and durable option that can smooth out some of the miscalculations made during the construction process. However, it is rather difficult to mount such a base.
• Column foundation it is a little easier and cheaper to build than a tape one. However, if at the site the soil tends to bulge, shrink or flood, then it is better to choose a different type of foundation.
• Pile foundation great for light mobile soils. However, its construction requires the use of special piles and the implementation of bored works, which may not be performed in all areas.

Construction rules

Tape

Such a foundation is made of brick, cinder block, rubble stone, reinforced concrete blocks or a monolith. It should run in a continuous strip under all structures of the building. This is to ensure that the weight is evenly distributed over the entire surface of the base. The laying is carried out using a cement-sand mortar, the height of the foundation should be from 50 to 80 cm, while 30 cm should fall on the buried part, and 20-50 - on the aboveground one.

If the site drowns heavily, then the basement part can be made higher.

To fasten the crown of a wooden house, threaded rods or side corners are installed in the foundation. Then a lattice of reinforcement, smooth metal rods, thick iron wire or small pipes is mounted. The lattice is laid on the bottom of a previously prepared trench in two rows at a distance of about 10 cm from the formwork, while the distance between the rods should be about 50 cm. The rods must be fastened together by welding or tying them with wire.

Depending on the depth of occurrence, it can be:

• deeply buried - for massive multi-storey structures;
• shallow - for a one-story wooden house;
• shallow - for light outbuildings.

Columnar

This type of foundation is chosen if the upper layers of the soil on the site cannot provide reliable support for the strip foundation. The pillars are made of bricks, blocks, or reinforced concrete. Their width should be about 20-30 cm more than the thickness of the walls of the house, and their height should be 3 times the width. Most of the height of the posts usually falls on the above-ground part.

The distance between the foundation pillars along the perimeter of the house should be 2-2.5 meters, while they must be installed under open or closed corners of the house, intersections and convergence of internal walls.

The technology for erecting a columnar base for a wooden house involves several stages:

• creation of a pillar layout;
• preparation of a trench around the perimeter of the house;
• concreting of pits;
• installation of pins and corners for mounting the first crown;
• laying a waterproofing layer on the sections of the pillars.

The upper part of the foundation pillars is connected by horizontal reinforced concrete beams that form the base of the house.

Pile

A similar base can be installed at any time of the year. It is ideal for moving soil, fast and inexpensive to install. There are two types of pile foundations.

Bored

To install it, you need to drill several holes in the ground with a diameter of about 20 cm at a distance of 2 m from each other. At the same time, it is important to install piles at the open and closed corners of the building perimeter, the points of convergence and intersection of its walls. Then it is necessary to lower the asbestos-cement pipes of the appropriate size into the prepared holes and align the height of the pipes to the required parameters. After that, three rods of reinforcement should be lowered into the pipe and everything should be poured with concrete. It remains only to install threaded rods and anchors on the upper end of the structure.

Screw-in

Its design involves screwing piles into the ground to the required depth. Piles can be screw, made of iron pipes with a head, blades and a tip.

Destruction

Practice shows that of all the listed options for the foundation, the old columnar base is most often destroyed. The problems with the foundation are evidenced by distortions of the walls, difficulties in opening doors and a window, blockage of one side of the house in a certain direction.

Causes

Below are some of the most common cases that indicate problems with the foundation.

• Strong deterioration of the old structure . This is evidenced by crumbling masonry and bricks, rotten wood and other defects.
• Destruction of the support pillar … If at least one of the pillars is broken, then the building structure may deform. Therefore, this should not be allowed - it is necessary to immediately take appropriate measures.
• Noticeable misalignment of the piles . This can occur due to incorrect calculations and construction errors.
• Cracking and chips in the strip base. Violation of the solidity of the base can lead to distortions of the house.
• Lowering the log house to the ground … This usually happens after several decades of operation.

These consequences can manifest themselves as a result of errors in the construction of the foundation or its dilapidation.

Determination of the degree

If you find at least one of these reasons, you should think about repairing or replacing the foundation. But first, you need to invite a specialist so that he draws up an accurate conclusion about the need for such work, and also clarifies that it is wiser to redo the base of the old building or build a new one.

When is repair only needed?

Complete replacement of the foundation under a standing wooden house is a rather radical, time-consuming and expensive procedure. Therefore, you should regularly check the condition of the base in order to avoid serious problems, because it is much easier, faster and cheaper to repair the material. For example, if small cracks are found in the foundation, then it is enough to fill them with cement to avoid further destruction.

If the house is noticeably lopsided, and the base has violated its integrity, then its complete alteration will be required.

Repair and strengthening of the foundation is carried out in cases where:

• the degree of subsidence of the building is higher than the permissible norms;
• there is a need to build a second floor;
• the structure is constantly exposed to any vibrations.

Strengthening is carried out by installing micropiles, cementing, updating brickwork, expanding the sole of the house and in other available ways. Such manipulations will help get rid of the cracks that have appeared and evenly distribute the load on the base when the house is standing.

How to replace it completely?

If the old foundation has sagged a lot and can no longer cope with its functions, it must be completely replaced with a new one.

The ways

Below are several ways to reconstruct foundations.

Cosmetic . This method does not require large monetary costs, therefore it is the most affordable. It involves replacing a destroyed or decayed part of the foundation with a wooden element. However, this method is not suitable for replacing a full base.

• With the dismantling of the walls . This is a very laborious process, since you will have to completely disassemble the walls. However, after that it will be easy to completely replace the slab foundation.
• With the dismantling of the base . This option involves dismantling the lower crown of the structure in order to fully and efficiently repair or completely change the foundation of a wooden house.

Base selection

To replace the base, the same material is used from which the old foundation is made. For example, a concrete base will need concrete and reinforcement.

Preparation and equipping

Before starting work, you need to prepare all the required tools. To rebuild the foundation of a wooden house with your own hands, you will need a scrap, a sledgehammer and wedges, as well as a jack for lifting the base, bars, beams and other materials.

If the replacement of the concrete slab cannot be restored manually, it is necessary to use special equipment for work . In particular, hydraulic jacks are suitable, which are capable of lifting loads up to 10 tons. Such cars can be rented from special companies.

You will also need strong beams, bricks and chocks for the construction of temporary supports, as well as boards for laying. And so that there are no problems with raising the crowns, you need to use a steel plate with a thickness of more than 5 mm.

Technology and stages

First, you need to carry out the transfer of all furniture from home and prepare for the fact that the work on replacing the foundation will take at least 6 weeks, depending on the speed of setting of the concrete solution.

The work is divided into several stages

• Installation of jacks . They should be located in a solid area of the base and used at a uniform rate to avoid damage to the crown of the house.
• Raising the structure . It is necessary to raise the walls 6 cm higher and remove the worn-out elements. It is first necessary to make supports from beams, treating each with an antiseptic. In place of the new base, you need to fill in 10 cm of gravel. It is important to raise the structure gradually: no more than 2 cm at a time on each side. After each climb, it is necessary to fix the position of the house with the help of log supports.

• Removing old material . The damaged masonry is dismantled using a crowbar and a chisel. If the foundation has retained its integrity in places, then it is left.
• Installation of a new foundation . First of all, it is required to prepare a trench, the depth of which will be deeper than the previous one. A sand cushion is poured at its bottom, then a reinforcing cage and a formwork for waterproofing are made up.

After that, you can start pouring the concrete solution. It will harden in about 2 weeks. After this time, boards and temporary supports are placed on the first section of the base. The frame of each next section is tied with reinforcement.

The final stage of the work will be the installation of the house on a new foundation. The fixing temporary beams are removed.

It is necessary to follow the rules and sequence of stages of work - then it will turn out to properly repair or replace the foundation under the wooden house.