- Light camber
- Average camber
- Strong camber
- Full blockage
- Partial blockage
- Outbuilding department
If it so happens that a crack has gone along the load-bearing wall or foundation, this is not yet a sentence, it’s just time to take radical measures to strengthen the entire structure. We will talk about the most simple and popular methods of preserving the integrity of a building in this article..
Note.The article uses conditional terminology.
When purchasing a ready-made house, the new owner in all cases deals with a pig in a poke. And it doesn’t matter if it’s a new building or an old renovated one. Builders build and renovate cottages and private houses in a fantastically short time, which always affects their stability and durability. Regardless of the reasons for its appearance, a crack is a frequent and faithful companion of stone buildings and structures. We will talk about the most difficult cases of these unpleasant and dangerous defects – structural cracks, which serve as signals of the appearance of the mobility of the bearing elements. To stop the development of the crack, the movement should be stopped and the elements should be fixed, and then repaired and “masked”.
Note.A crack in the finish does not always mean the presence of defects in the wall material. Make sure that it is the carrier material that is damaged by removing some of the trim and exposing the defective area for observation.
Let’s leave the theory and consider the three most common cases of the appearance of element mobility: collapse, blockage and separation of the extension.
In the event of a collapse, the walls and corners have a visual outward deviation from the vertical, sometimes wavy. Walls can also be deformed in waves or deflected by the entire plane. In most cases, this is accompanied by the appearance of cracks in the upper corners of door and window openings..
By the degree of coverage, the collapse can be:
- Complete. All load-bearing external walls are deformed to varying degrees.
- Incomplete (partial). Some walls are deformed.
In both cases, even if only one wall is collapsing, we recommend applying a preventive screed on all sides to prevent the development of movement on other walls..
Depending on the degree of collapse of the walls, measures of different depth of influence are used. We will conditionally divide the degree of collapse into three categories – light, medium and strong, and tell you what to apply in each case..
The tops of the walls are noticeably deformed in the area up to 1/3 of the height of the wall (without the height of the foundation). Cracks in the corners of openings in 50% of cases. The rest of the walls and foundation are normal (no cracks, deformations).
It occurs due to the unreliability or lack of an armored belt, roof overload, when building an attic floor on old walls.
Note.The most common mistake leading to roof overload is unaccounted snow load.
In this case, it is reasonable to use a steel mono-yoke (hereinafter referred to as the cage) on the corner stops for screed walls. At the same time, as in all cases of using various cages, the rods will pass from the outside along the facade of the load-bearing walls, standing in the shape of a rectangle. Sometimes it is necessary to make technological openings for rods in the walls of the outbuildings.
What you need:
- Steel corner 100×100 mm (minimum 75×75) – 4 m.
- Pipe 1 inch – 1 m.
- Threaded hairpin 20 mm – 4 m.
- Stud nuts and washers.
- A circle (steel bar) with a diameter of 20 mm or a strip of 40×4 mm – as long as the perimeter of the house.
- Welding, painting.
Note.It is undesirable to use reinforcement for rods, since it is not designed for outdoor work and is subject to corrosion.
How to make a corner stop: on a steel corner 100×100 mm long equal to the distance from the top of the wall to the top of the window openings plus 20%, pipe sections 150 mm long are welded.
The number of stops is equal to the number of corners (4).
- Rods (strips) are welded into two continuous lashes along the walls of the house minus 200 mm (per tightening stroke).
- Then at the ends of the stitches, studs with a free end of 200 mm are welded.
- The pins are threaded into the tubes and the whips are welded together in the middle.
- The whole structure is assembled on the ground and fixed at the required height.
- The nuts are tightened to a state of tension.
Attention! When using steel clips and ties, remember that they are for anchoring walls. An attempt to return the walls to their original state can result in breaks and sagging areas.
The design of the steel race may vary. For example, in the case of undulating deformations, a channel can be used as one, several or all four rods. Installation will be more difficult, but the entire load from the wall will be evenly distributed over the rigid channel.
All signs of light collapse extend to 50% of the wall height (excluding the foundation). The probability of cracks in the corners and boundaries of openings – 80%.
Weak armopoyas. Lack of a bunch of corners and masonry in the wall material, high material wear, overload.
In these cases, a solid corner frame is used. It is arranged similarly to a mono-holder, but along the entire height of the wall and has more tie belts. With an average camber, it is recommended to arrange three belts.
In all cases, the circle can be replaced with a steel strip 10×40 mm.
Attention! The welds must be of good quality (they hold the load). Overlap – 250 mm.
All signs of medium and light, but at a level of over 50% In the overwhelming majority of cases, it is accompanied by the appearance of deep, sometimes open, cracks along the walls and foundation.
Most often, deformations of the base or foundation are combined with the causes of slight to medium collapse. May be accompanied by partial destruction of the foundation.
For repair, use a solid corner frame and a retaining wall (support) or a retaining belt of the foundation.
Retaining wall or support – part of the reinforcement belt applied in the deformed area.
Retaining belt is a repair structural element designed to reinforce existing foundation walls along their entire length. It is used when it is necessary to strengthen the foundation. Material – reinforced concrete.
Backwater device. Let’s consider an example of a corner section. A solid belt is arranged in a similar way..
First you need to determine the size of the backwater. If we had to resort to such drastic measures, it means that it is too late to calculate the load, especially since the existing foundation remains in place. Therefore, we simplify the calculations towards increasing the safety factor. The backing thickness should be 50% of the foundation wall thickness, but not less than 400 mm. If possible, the bottom of the backwater and the foundation should be at the same level. The optimal ratio of the aboveground to the underground is 1 third above the ground, 2 thirds below the ground.
Attention! Reinforcement rods at the corners must be solid (bent at 90 °). The minimum side of the corner support is equal to three support thicknesses.
- We excavate the damaged area and clean the trench. We clean the wall of the foundation from oils and organics, residues of waterproofing.
- We drill holes with a diameter of 18 mm into the wall of the foundation to a depth of 200 mm in a checkerboard pattern with a step of 200 mm.
- We drive in reinforcing pins with a diameter of 16 mm and a length equal to the thickness of the backing plus 200 mm (driven into the wall) minus 40 mm (protective layer).
- We tie working fittings with a diameter of 16 mm with a pitch of 200 mm to the pins with a knitting wire.
- We make U-clamps from 10 mm reinforcement to the dimensions of the frame of the beam (support) 600x360x600 mm (workpiece length 1600 mm) and install them with a step of 200 mm.
- We install the formwork by size.
- We lay concrete (factory or prepared on site) with vibration.
- After the concrete has set (3 days), we remove the formwork and apply waterproofing.
- We carry out backfilling of soil with ramming and pouring.
Backwater reinforcement: 1 – foundation; 2 – working L-shaped rods O 16 mm; 3 – formwork; 4 – U-shaped clamps O 10 mm; 5 – rods driven into the foundation, Ø 16 mm
Device costs 1 lin. m backing with a thickness of 400 mm, a height of 600 mm when making concrete on site:
Name Unit rev. Qty Unit price, rub. Total cost, rub. Note Rebar 16 run. m 20 thirty 600 Wall pins and work rods Rebar 10 run. m ten 20 200 U-shaped clamps Knitting wire Kg 0.5 200 one hundred Anchoring all wireframe elements Concrete cub. m 0.25 1000 250 Waterproofing sq. m 1 20 20 Formwork costs sq. m 1 one hundred one hundred Self-tapping screws, nails, boards Additional expenses – – 300 300 Disks, drill, etc.. Total material 1570 Depends on local conditions and contract Job 1000 Total material and work 2570
The walls are piled up inside the building. It can be complete or partial (incomplete). In different degrees of deformation (light, medium, strong) one stop method is used.
Note.To repair the blockage, it will be necessary to carry out welding work inside the premises, which is most often associated with a major overhaul of the entire building. Take care of fire safety.
Three or more walls are piled up inside the building (to varying degrees).
Weak armored belt, material wear, violation of technology during construction (weak solution, lack of corner reinforcement, etc.).
Rigid spacer self-supporting steel cage (frame) on through fastening.
What you need:
- Rotary hammer with a drill 18-20 mm.
- Channel 50×100-150 – length equal to the perimeter of the walls to be reinforced.
- Steel plate 200x200x3-4 mm (up to 300×300).
- Rebar 16 – 3 wall thicknesses for each running meter of the frame.
- Good welding (tension), painting.
- Determine the perimeter of the walls to be reinforced. If necessary, we punch technological holes (for the channel) in the partitions.
- We divide each wall into steps close to 600-700 mm (but no more). Are we retreating from every corner? step.
- We drill through holes 18–20 mm.
- On steel plates, perpendicularly weld reinforcement pins with a length equal to the wall thickness plus 100 mm.
- We install the resulting anchors into the holes with the plate outward.
- Trying on each channel from the inside, mark it under the holes.
- We burn by welding the holes in the channel for the reinforcement.
- We paint the outer shelf of the channel with a primer (it will adhere to the wall).
- We install the channel on the pins in the holes.
- Weld the pins in the holes.
- In the same way, we install the continuation of the channel.
- When the entire perimeter is installed, we weld the channel to each other along the joint and make welded linings from reinforcement 16 – 2 per joint with an overlap of 300 mm.
- We strengthen the corners in any way possible (for welding).
Ideal for such a holder – if it will then be covered with a suspended ceiling. Then you can arrange diagonal rods. If a suspended ceiling is not expected, close the tire with a box.
Attention! The plates on the outside and the reinforcement welded to them, passing inside the wall, are a strong cold bridge and it will destroy the wall with condensation. Be sure to insulate the plates, and preferably the entire wall..
One or two walls are overwhelmed.
The walls are located close to a busy roadway (with tram). Washing with atmospheric waters.
Partial cage arrangement according to the solid principle. The side of the interrupted corner is equal to one third of the length of the heaped wall, but not less than 1.5 meters.
Arrangement of a partial inner cage: 1 – wall with a blockage; 2 – reinforcement with a plate; 3 – channel 100x50x4 mm
In case of combined collapses / rubble (when the walls diverge in different directions), use the inner frame (first of all) and the outer screed (secondly) together. In severe cases, use all the enhancement options at once or their combination.
Calculation of the cost of 1 running meter of the inner cage:
Name Unit rev. Qty Unit price, rub. Total cost, rub. Rebar 16 run. m 1 thirty thirty Channel 100x50x4 run. m 1 200 200 Plate 300x300x4 PCS. 2 150 300 Primer – – 20 20 Total material 550 Job 1000 Total material and work 1550
Consider the most difficult and at the same time popular case – the combined.
A through crack along the inner corner or at the junction of the extension with the main building with a medium or strong collapse of the outer wall.
Lack of attachment to the wall of the main building during the construction of the extension (in 90% of cases). Weak foundation under the walls of the extension. Extension overload (superstructure, balcony).
A combination of a through, semi-through or anchor clip and back-up:
- Through cage – the rods pass through the load-bearing wall and are fixed (nuts, welding) on a thrust bar or plate located on the inside of the wall.
- Semi-through cage – one side is of the through type, the other is fixed from the outside to the embedded part.
- Anchor clip – the rods are attached to embedded parts, arranged on anchors in the walls of the building.
Extension screed options: 1 – semi-through; 2 – through; 3 – anchor; 4 – corners 100×100 mm; 5 – rods (rod, plate); 6 – capital walls; 7 – plate with anchor; 8 – plate 4 mm
You can arrange any of these types of clips using the instructions above..
Rules for the construction of anchor rods:
- A thrust bar or plate located inside the building must not hit the top of the doorway.
- Arrange embeddable parts in the walls at a distance of 1/3 of the extension wall length, set aside from the junction of the walls, but not less than 1.5 meters. Drill 3 points diameter from 12 mm, depth 2/3 of the wall thickness.
- If the number of anchor rods is more than 2, place them with a break in length of 1 meter.
- The walls of the main building should not have deformations and cracks.
The support can be either separate (under the outer wall) or along the entire length of the extension foundation. In this case, the reinforcement is driven into the foundation of the main building at an angle.
Most often, the types of deformations described above occur in houses made of marl or bricks laid on clay. Even in the case of the initial stage of deformations (the appearance of small cracks), we recommend using a preventive screed at home on corner frames. Remember that any metal passing through the wall into the room is a cold bridge and will negatively affect the condition of the wall if it is not insulated.