Special Concrete Repair

Gunner provides foundation repair, levelling, underpinning and raising. We also do concrete levelling, mudjacking, liquid topsoil and backfill and much more. We have years of experience serving residential, commercial and industrial customers in the Prairie Provinces.

 

Services

Compaction Grouting

Regina and area is known for its volatile clay soil conditions. This can result in inadequate support of foundations. Compaction grouting is a recognized structural engineering method of repairing settled foundations. Like most major repairs, proper application by an experienced team of professionals is essential.

How does it work? Grout injection pipes are installed below foundation footings or pilings to raise the foundation and improve poor ground conditions. Special equipment is used to mix and inject the materials under high pressure. This creates very low impact to the surrounding landscape.

A stiff mortar grout is injected into the subsurface soils under high pressure. This supports and thickens the soil while filling voids. The key us to effectively place and control the flow of grout. We accomplish this by using a very stiff, granular grout combined with concrete cone slumps in the range of ½” to 2 ½”. Using less stiff grout can result in loss of control of the grout location, fracturing of the grout, ground splitting, and grout migrating away from the intended treatment area.

The selection of the right mortar and consistency is essential to the project’s success. This is where our prior experience comes in. Our grout allows pressures in excess of 500 PSI to be used, resulting in an ideal grout bulb shape forming within the intended treatment zone.

Some of the conditions that can be treated by compaction grouting materials include:

• Stabilizing poor backfill material under footings and slabs, as well as behind retaining walls.
• Densification of tunnel crown soils during soft ground tunnelling operations.
• Reducing surface settlements to eliminate the need for costly and messy underpinning.
• Improvement of slope stability.

Our experience allows us to accurately diagnose the cause of foundation distress and properly evaluate the subsurface. We can then apply the right material in the right place to correct the issue. We carefully monitor the worksite to observe any heave and verify the effectiveness of the grout application.

Whether you are looking to incorporate compaction grouting into your design, or need to remediate ground stabilization problems, Gunner is here to help.

Shotcrete & Gunite

Shotcrete is a structurally engineered sprayed concrete used to repair foundations. In addition, it can be used to restore concrete, stabilize slopes, repair swimming pools and improve water erosion control.

There are many benefits to shotcrete:

• Shotcrete builds upon itself, covering steel reinforcements while adhering to the wall.
• The result is a very dense, high strength, waterproof concrete.
• Existing wall cracks and irregularities are filled with by shotcrete.
• The foundation wall is now structurally superior to new foundation walls, at a fraction of the cost.
• The work’s structural integrity is protected by the work of local engineers, who prepare structural drawings and do site inspections.
• Work can be completed in any season of the year, generally within a week.
• There is little disturbance to the building occupants and the surrounding landscape.
• Engineered shotcrete foundation repair is recognized by the Central Mortgage and Housing Corporation (CMHC).

Liquid Topsoil

Homeowners often invest time and effort using topsoil to improve the grading around their foundation. The result is often further settling of the soil soon after the work is complete. This can result in water running towards the house, as well as damaged landscape features.

Liquid topsoil is another landscaping innovation from Gunner. Liquid topsoil can be applied within a few hours, improving the landscape grade, covering underground sprinklers, preparing for sod, and more. It eliminates soil compaction as well as the need for shoveling, wheelbarrows, and your time.

The process is quick and easy, and makes a great compliment to our Liquid Backfill process.

Jack-Down Piling System

We refer to jack-down piles as smart piles because they self-design based on the structure’s load requirements.

This system is a great compliment to Compaction Grouting when foundations need to be raised and underpinned.

An excavation is don below the foundation footings. A high pressure hydraulic jack and an interlocking steel casing section are then used. New steel casing sections are added and jacked down into the bearing ground, using the foundation’s weight as resistance. The installation continues until the resistance is able to permit elevation of the structure.

When installation is complete, the structure is raised incrementally to the required elevation. The steel casings are then filled with concrete.

The installation can be done from the exterior, or even within the basement area. This allows the jack-down piling system to level and underpin foundations any time of the year.

Foundation Underpinning

Sometimes, foundation settling reaches a point where lifting the structure back to its original elevation should be considered. This point is generally in the range of 2” or more of settlement.

The process of underpinning involves the installation of piles into a zone of stable soil below the foundation walls. Our preferred method is jack-down piles. These smart piles structurally design themselves. Interlocking steel pipes are hydraulically forced into the bearing soil, using the structure itself as resistance.

As many as 10 to 20 of these pipes may be used. Installation continues until enough resistance is attained to lift the structure. If only stabilization is required, work stops there. Otherwise, all pipe locations are incrementally raised until the foundation is raised and leveled.

Each pile is then filled with concrete and capped of, create an underpinning support system that could easily last lifetimes.

Our underpinning method is an excellent structural addition to historic properties. Whether a historic home or your own private castle, be sure to contact us at Gunner about your foundation settlement concerns.

Rental Arrangement

Hire Gunner to do the job or rent one of our units to get it contracted yourself. We rent boom pumps, trailer line pumps and placement line assemblies. We can even provide you with a contract equipment operator and/or equipment training.

Clay Spray

Clay spray is used to stabilize slopes, control washout and provide excavation safety. This application fills and rebuilds slop washout, sluff-ins, sinkholes, cavities and more.

Mudjacking/Slabjacking

Mudjacking is known by several terms – slabjacking, concrete raising, concrete lifting, slab raising and slab lifting. The process is the same for all – a stabilizing grout material is pumped underneath the slab through 1¼” drilled holes to fill voids and raise the concrete to its original height.

The consistency of the grout is adjusted to best suit the site conditions. The grout material then hardens to provide a stable sub-base that doesn’t erode or settle. The drilled holes are then patched with cement.

Mudjacking offers several advantages over other methods.

• Less costly than concrete replacement.
• Faster and cleaner than other methods.
• Can be done at night or off hour times.
• The grout can be pumped long distances, meaning access space for large equipment is not required.
• The surface texture and appearance is maintained.
• Stabilizes and provide a semi-structural bridge support.
• Keeps water from migrating beneath the slab where it can freeze/thaw and create damage.
• Helps protect nearby concrete structures from water damage.
• Properly executed mudjacking will not create new cracks, but hardly visible existing cracks may tend to open with sagged areas.

In a typical settled slab illustrated here, cracks are wider at “A” and “D” on the top and “B” and “C” on the bottom. On the surface, cracks “A” and “D” (in tension are wide and visible, while cracks “B” and “C” (in compression) are either very fine or not visible at all. Mudjacking will produce a closing force on cracks “A” and “D”, and an opening force on “B” and “C” as the slab is being raised.

When large areas of concrete must be raised, mudjacking is typically the most economical and practical method. Injection holes are created every 3 – 4 feet, depending on the strength, thickness, condition and configuration of the concrete slab. This creates an distribution of weight over many injection holes. Rotary percussion drills are typically used, but core drilling can be done when required.

Our experienced staff will develop the optimal layout and hole spacing for your project.

Injection usually starts at the point of greatest settlement. Lifting is done at about ¼” intervals at all points. A stiff grout is used to maintain better control and prevent leakage at slab edges. A more flowable grout is then used to fill all remaining cavities. This is an important step that many other contractors do not follow.

Poor equipment, materials and techniques result in disappointing projects, which is why our experience can be such a great asset. Most customers who are left with inadequate work cannot visibly see voids left under the slab, potential seepage conditions, or new cracks waiting to emerge until it’s too late.

Foam jacking has recently entered the market in an attempt to compete with mudjacking. Foam that uses hazardous and toxic chemicals are used, and produce a result that is less durable than mudjacking. We do not support this technique.

Liquid Backfill

Liquid backfill is a pumpable, water impervious clay based material that can improve landscape grading around foundations and fill voids and cavities. It can even be used to backfill new foundations, preventing future grade settlement and water problems.

Liquid backfill can be used for shifting and cracking foundations, settled patios, driveways and sidewalks, and heaving basement floors.

Everyone strives to create low maintenance, long lasting structures that don’t require expensive future repairs. The proper backfilling of foundations is essential to ensure its durability and sustainability. Neglecting backfilling standards results in shifting foundations, water damage, and landscape damage. Most foundation problems can be attributed to the direct or indirect impacts of backfill settlement.

Many people place too much confidence in weeping tile to protect their foundation. Poorly installed weeping tile can actually create more problems than it solves, creating low spots that can trap water and undermine a foundation.

• Expansive clay like Regina’s can cause foundations to settle in three ways.
• The weight of the foundation causes it to sink in water softened soil. Think of your boot in heavy mud.
• Flash rains and floods can remove material from under a footing.
• Tree roots grow in search of moisture rich weeping tiles. This results in shrinkage of the bearing soil.

It is very important that the moisture condition at the depth of footings is maintained at a consistent moisture level, similar to the original moisture condition at the time of excavation. Complying with this simple rule will ensure a stable ground and foundation condition.

As industry experts, we do not recommend topsoil be used for grading and backfilling for several reasons:

• Organic material within topsoil decomposes, resulting in settlement.
• Topsoil doesn’t compact wll.
• Topsoil does not shed water, instead absorbs it until saturated.

Concrete Pumping & Pump Term Rentals

Gunner has worked in almost every pumping and weather conditions. We’ve worked with everything from houses to pulp and steel mills to high rises. We can help you find the ideal concrete or grout pump for your job.

Our Concrete Pump types are:

• ELBA Boom Pump (31m) (100 + Cubic yards/hr.)
• ELBA Boom Pump (28m) (100 + Cubic yards/hr.)
• SCHWING Line Pumps (70+ Cubic yards/hr.)
• REED Line Pumps (50+ Cubic yards/hr.)
Our specialty Grout Pumps is the ACKER Colgrout Unit (a colloidal grout mixer/pump).

Rental Equipment

1982 Elba Concrete Pump Model 8030 Boom
• Extension 105′ Reach
• Twin Wall Pipe 106 ubic Yd/Hr – piston pressure 863 PSI
• Mounted on: 1996 Peterbilt 320, 300hp, 10 speed, air conditioning, kysor system, am/fm tape, (low operating hours like new).

1982 Elba Concrete Pump Model 8024 Boom
• Extension 85′ Reach
• Twin Wall Pipe 106 Cubic Yd/Hr – Piston Pressure 863 PSI
• Mounted On: 1996 Peterbilt 320, 300hp, 10 Speed, Air Conditioning, Kysor System, Am/Fm Tape, (Low Operating Hours Like New)

SCHWING 750-18 Concrete Trailer Pump
• 69 Cubic yards per hour
• Construction or mine operation
• Low Hours, very reliable condition