Constructed of concrete, stairs can withstand the elements and are a great way to enhance architectural appeal or bridge a change in elevations on your property. Sure, you can hire a contractor to build concrete stairs for you, but if you are handy and have some construction experience, you can save a bundle by doing it yourself. Here’s a step-by-step guide to help you build concrete stairs that will last for years to come.
Before you begin, you need to determine the location of your stairs, the number of steps required, and the dimensions of each step. You will also need to gather the necessary materials, including concrete mix, rebar, gravel, sand, and lumber for the forms. Once you have all of your materials, you can begin constructing the forms for your stairs. The forms will determine the shape and size of your stairs, so it is important to make sure they are accurate. Once the forms are in place, you can pour the concrete. Be sure to vibrate the concrete to remove any air bubbles and ensure a strong bond. After the concrete has cured, you can remove the forms and finish the stairs to your liking.
Building concrete stairs is a rewarding project that can add value to your home. By following these steps, you can create a beautiful and durable set of stairs that will last for years to come. If you have any questions or concerns, be sure to consult with a qualified contractor.
Excavation and Formwork
Excavation
Excavation is the process of digging out the soil to create a cavity in which to place the concrete stairs. The size of the excavation will depend on the dimensions of the stairs, including the number of steps, the width of the steps, and the overall height of the stairs. When excavating the area, it is important to dig down to a depth that is below the frost line to prevent the stairs from shifting or cracking due to freezing and thawing of the ground.
Steps for Excavation:
- Mark the location of the stairs using stakes and string.
- Excavate the area to a depth that is below the frost line, typically 36 inches deep.
- Create a level base for the stairs by grading the soil.
- Compact the soil to create a firm foundation for the stairs.
Formwork
Formwork refers to the temporary structure built to hold the concrete in place while it cures. It is typically made from plywood or lumber and is shaped to conform to the desired shape of the stairs. The formwork must be strong enough to withstand the weight of the concrete and prevent it from leaking out.
Steps for Formwork:
- Build the formwork using plywood or lumber.
- Secure the formwork in place using stakes or clamps.
- Apply a release agent to the formwork to prevent the concrete from sticking.
- Check the formwork for levelness and squareness.
| Material | Thickness |
|---|---|
| Plywood | 3/4 inch |
| Lumber | 2×4 inch |
Concrete Preparation and Placement
1. Concrete Preparation
Before placing concrete, it is critical to prepare the site properly. This includes clearing the area of any debris, leveling the ground, and installing the necessary formwork. The formwork should be sturdy enough to support the weight of the concrete and should be level and square to ensure that the stairs are straight and even.
2. Concrete Placement
Once the site is prepared, the concrete can be placed. The concrete should be mixed according to the manufacturer’s instructions and should be poured into the formwork in layers. Each layer should be tamped or vibrated to remove any air pockets and ensure that the concrete is well-compacted.
The concrete should be allowed to cure for at least 28 days before removing the formwork. During this time, the concrete should be kept moist to prevent cracking.
| Concrete Mix Design | Proportions |
|---|---|
| Standard Concrete | 1 part cement, 2 parts sand, 3 parts gravel |
| High-Strength Concrete | 1 part cement, 1.5 parts sand, 2 parts gravel |
| Low-Slump Concrete | 1 part cement, 2 parts sand, 3 parts gravel, less water |
Finishing and Curing
Finalizing the Surface
Once the concrete has set, you can begin finishing the surface. Use a concrete finishing trowel to smooth out any imperfections and create a level surface. For a smoother finish, you can apply a concrete resurfacer or a skim coat of mortar.
Adding Non-Slip Texture
To enhance safety, add a non-slip texture to the stairs. You can achieve this by using a broom finish, dragging a stiff-bristled brush across the surface while the concrete is still wet. Alternatively, you can sprinkle non-slip additives, such as sand or grit, into the surface during the finishing process.
Curing
Proper curing is essential to ensure the strength and durability of concrete stairs. Keep the stairs moist by covering them with plastic sheeting or burlap. Water should be applied regularly to maintain the moisture level and prevent the concrete from drying out too quickly. The curing period typically lasts for 7 to 14 days, depending on weather conditions.
Curing Table
| Day | Watering | Covering |
|---|---|---|
| 1-3 | Twice a day | Plastic sheeting or burlap |
| 4-7 | Once a day | Plastic sheeting or burlap |
| 8-14 | As needed | Plastic sheeting or burlap |
Safety Considerations
Building concrete stairs requires careful attention to safety. Here are some key considerations:
1. Fall Protection
Install temporary guardrails or barricades around the work area to prevent falls. Wear slip-resistant shoes and use ladders with non-slip rungs.
2. Sharp Objects
Wear gloves when handling sharp tools and materials, such as rebar and formwork. Keep the work area clear of debris and trip hazards.
3. Electrical Hazards
Use only grounded power tools and equipment. Keep cords away from water and ensure they are in good condition.
4. Health Hazards: A Deeper Dive
a. Dust
Concrete dust can be harmful to respiratory health. Wear a respirator or dust mask when working with concrete, especially when grinding or cutting.
b. Silica
Concrete contains silica, a mineral that can cause scarring in the lungs. Use a wet saw or grinder to reduce silica dust exposure.
c. Noise
Construction work can generate excessive noise. Wear earplugs or earmuffs to protect your hearing.
d. Chemical Hazards
Concrete additives and curing compounds can release harmful chemicals. Read and follow the manufacturer’s instructions carefully.
| Safety Hazard | Prevention Measures |
|---|---|
| Fall Protection | Guardrails, slip-resistant shoes, non-slip ladders |
| Sharp Objects | Gloves, clean work area |
| Electrical Hazards | Grounded tools, good cord condition |
| Dust | Respirator, wet cutting/grinding |
| Silica | Wet cutting/grinding |
| Noise | Earplugs/muffs |
| Chemicals | Follow manufacturer’s instructions |
Construction Joints and Reinforcements
Concrete stairs are typically constructed in one continuous pour, but in some cases, it may be necessary to create a construction joint. A construction joint is a planned discontinuity in the concrete that allows for the concrete to be poured in separate stages. Construction joints should be placed at the following locations:
– At the bottom of the stairs
– At the top of the stairs
– At any landings or changes in elevation
When creating a construction joint, the following steps should be taken:
1. The surface of the concrete should be roughened to promote bonding between the two pours.
2. A layer of bonding agent should be applied to the surface of the concrete.
3. The concrete should be poured in the second stage.
Reinforcements
Concrete stairs require reinforcement to prevent cracking and failure. The reinforcement should be placed in the following locations:
Main Reinforcement
The main reinforcement consists of rebar that is placed longitudinally in the stairs. The rebar should be spaced at a maximum of 12 inches on center.
Distribution Reinforcement
Distribution reinforcement consists of rebar that is placed transversely in the stairs. The distribution reinforcement should be spaced at a maximum of 18 inches on center.
Stirrups
Stirrups are U-shaped pieces of rebar that are placed around the main reinforcement. Stirrups help to prevent the main reinforcement from buckling and provide additional support to the concrete.
| Bar Size | Spacing |
|---|---|
| #4 | 12 inches on center |
| #3 | 18 inches on center |
| #2 | 6 inches on center |
Stair Design and Dimensions
Before constructing concrete stairs, it’s crucial to design them carefully, considering their dimensions and adhering to building codes and safety regulations. Here are key factors to consider:
Tread Depth and Height
Tread depth (the horizontal portion where you step) should range from 254mm to 305mm, while tread height (the vertical rise between treads) should be between 152mm and 190mm. These dimensions ensure ease of use and prevent tripping.
Riser Height
The riser height should be consistent throughout the staircase, typically ranging from 152mm to 190mm. Uniform riser heights promote safe and even ascent and descent.
Stair Width
The minimum recommended stair width is 914mm, allowing for comfortable passage of individuals and objects. However, wider stairs may be necessary for higher traffic areas or accessibility considerations.
Nosing Projection
Nosing is the projecting edge of the tread that extends beyond the riser. It provides additional safety by creating a visible and tactile cue that prevents tripping and slipping.
Handrails
Handrails are essential for safety, providing support and stability. They should be installed on both sides of stairs with a minimum height of 864mm and a diameter or width suitable for gripping.
Headroom
Headroom, the vertical distance between the top of the staircase and the ceiling, should be sufficient to prevent head injuries. Building codes typically require a minimum headroom of 2032mm.
Surface Treatment and Finishing
Exposed Aggregate Steps
Exposing the coarse aggregate in the concrete creates a visually appealing and durable finish. This method involves removing the cement paste from the surface of the steps after they have cured. Techniques like water blasting, grinding, or acid etching can be used.
Broom Finish
A broom finish provides a non-slip surface by creating small grooves. It’s achieved by using a stiff broom to texture the concrete as it sets. This finish is commonly used for exterior stairs.
Stamped Concrete Steps
Stamped concrete mimics the appearance of other materials like stone or brick. Stamps with different patterns are pressed into the wet concrete, creating a decorative finish.
Colored Concrete Steps
Adding pigments to the concrete mix creates colored steps. This adds aesthetic appeal and can complement the surrounding landscape or architectural style.
Grinding and Polishing
For a smooth and glossy finish, concrete steps can be ground and polished. This process involves using diamond-abrasive grinding discs to smooth out the surface and create a high shine.
Paint
Painting concrete steps is a cost-effective way to change their color and appearance. However, paint can wear off over time, requiring periodic touch-ups.
Surface Sealer
Applying a surface sealer adds a protective layer to the concrete, making it resistant to stains, moisture, and salt damage. It also enhances the appearance of the finish.
| Treatment | Benefits |
|---|---|
| Exposed Aggregate | Durable, visually appealing, non-slip |
| Broom Finish | Non-slip, suitable for exterior use |
| Stamped Concrete | Decorative, mimics stone or brick |
| Colored Concrete | Adds aesthetic appeal |
| Grinding and Polishing | Smooth, glossy finish |
| Paint | Cost-effective, changes color |
| Surface Sealer | Protective, enhances appearance |
Inspection and Testing
Once the concrete stairs are complete, it’s important to inspect them to ensure they meet the required specifications. This includes checking for any defects, such as cracks or voids, and verifying the overall structural integrity of the stairs.
Visual Inspection
Begin by conducting a thorough visual inspection to identify any visible cracks, voids, or other imperfections. Examine the surface of the concrete for any signs of damage, such as spalling, chipping, or discoloration.
Level and Slope Measurement
Using a level, verify that the stairs are level and have the correct slope or pitch. The slope should be gradual enough to allow for safe and comfortable walking, while still providing adequate drainage for water.
Handrail Inspection
Inspect the handrails to ensure they are securely attached and at the appropriate height. Check that the handrails are free of any sharp edges or obstructions.
Structural Testing
In some cases, it may be necessary to conduct structural testing to confirm the load-bearing capacity of the stairs. This can involve applying a known load to the stairs and monitoring its deflection to ensure it meets the design requirements.
Nondestructive Testing
Nondestructive testing methods, such as ultrasonic testing or ground-penetrating radar, can be used to detect internal defects within the concrete that might not be visible to the naked eye.
Acceptance Criteria
The acceptance criteria for the stairs should be defined in the project specifications. These criteria will determine whether the stairs meet the required standards and can be accepted for use.
Table: Acceptance Criteria for Concrete Stairs
| Criteria | Requirements |
|---|---|
| Visual Inspection | No visible cracks, voids, spalling, or discoloration |
| Level and Slope Measurement | Level within 1/4 inch over a 10-foot span Slope within 1:12 |
| Handrail Inspection | Securely attached at appropriate height (34-38 inches), with no sharp edges |
| Structural Testing | Deflection meets design requirements |
| Nondestructive Testing | No significant internal defects detected |
Maintenance and Repairs
To keep your concrete stairs looking their best and functioning properly, it’s important to regularly inspect and maintain them.
Cleaning
Regularly remove dirt, debris, and stains from the stairs using a mild detergent and water. Avoid using harsh chemicals that can damage the concrete.
Sealants
Apply a penetrating concrete sealant to the stairs every few years to protect them from moisture and dirt.
Expansion Joints
Inspect the expansion joints between the stairs and the surrounding area. If any cracks or gaps appear, fill them using a suitable sealant.
Caulking
Caulk any cracks or gaps around the stairs where water can seep in.
Repairs
If you notice any cracks or damage to the concrete, it’s important to address them promptly to prevent further deterioration:
Minor Cracks
Small hairline cracks can be filled using a patching compound specifically designed for concrete.
Larger Cracks
Cracks that are wider than 1/4 inch should be repaired by a professional contractor using epoxy or other suitable materials.
Crumbling Concrete
If the concrete is crumbling or spalling, it may need to be replaced. This is a more extensive repair that should be performed by a professional.
Steps to Repair Cracks:
| Step 1: Clean and Prepare | Thoroughly clean the crack and remove any debris using a brush and water. |
|---|---|
| Step 2: Widen and Deepen | Use a chisel or grinder to widen and deepen the crack to create a “V” shape. |
| Step 3: Apply Epoxy | Mix the epoxy according to the manufacturer’s instructions and apply it into the crack. |
| Step 4: Smooth and Finish | Smooth the epoxy using a putty knife and allow it to cure for the recommended time. |
Troubleshooting Common Issues
1. Cracks in the Concrete
Cracks in the concrete can be caused by several factors, including:
To prevent cracks, use proper reinforcement, cure the concrete properly, and ensure the foundation is stable.
2. Uneven or Sloping Stairs
Uneven or sloping stairs can be caused by inaccurate formwork or improper screeding. To ensure level stairs, use a level to check the formwork before pouring the concrete. Use a screed board to level the concrete as it is poured.
3. Slippery Stairs
Slippery stairs can be hazardous. To prevent slipping, add a non-slip surface to the stairs, such as a textured finish or a tread material with high friction.
4. Water Damage
Water damage can weaken the concrete and cause it to deteriorate. Protect the stairs from water damage by providing proper drainage and sealing any cracks or joints.
5. Rust on Reinforcement Bars
Rust on reinforcement bars can weaken the structure and lead to premature failure. To prevent rust, use galvanized reinforcement bars or epoxy-coated bars. Properly cover the reinforcement bars with concrete to protect them from moisture.
6. Spalling Concrete
Spalling concrete occurs when the surface of the concrete breaks away. This can be caused by:
To prevent spalling, use a concrete mix with air entrainment and protect the concrete from moisture and chemicals.
7. Efflorescence
Efflorescence is a white or powdery substance that forms on the surface of the concrete. This is caused by the evaporation of water that carries dissolved minerals to the surface. To prevent efflorescence, use a concrete mix with low water content and protect the concrete from moisture.
8. Alkali-Silica Reaction (ASR)
ASR is a chemical reaction that occurs between certain types of aggregate and alkalis in the cement. This reaction can cause the concrete to expand and crack. To prevent ASR, use an aggregate that is non-reactive with alkalis.
9. Creep
Creep is the slow deformation of concrete under sustained load. This can cause the stairs to sag or crack over time. To minimize creep, use a concrete mix with a low water-to-cement ratio and avoid overloading the stairs.
10. Fire Resistance
Concrete can lose its strength and collapse under fire conditions. To improve fire resistance, use a concrete mix with a high compressive strength and add fire-resistant fibers or aggregates. Protect the stairs from direct flame exposure by applying a fire-resistant coating or insulation.
How to Build Concrete Stairs
Concrete stairs are a durable and attractive addition to any home. They can be built in a variety of shapes and sizes to fit any space. If you’re planning to build concrete stairs, there are a few things you’ll need to do to ensure a successful project.
First, you’ll need to determine the location of your stairs. Once you know where you want them to go, you can start to plan the layout. The most important thing to consider is the slope of the stairs. The slope should be gradual enough that people can walk up and down them easily, but not so steep that they’re dangerous.
Once you have the layout planned, you can start to build the forms. The forms will hold the concrete in place while it cures. The forms should be made of wood or metal, and they should be strong enough to support the weight of the concrete.
Once the forms are built, you can start to pour the concrete. The concrete should be mixed according to the manufacturer’s instructions. When pouring the concrete, be sure to work quickly and evenly. You want the concrete to cure evenly, so don’t overwork it.
Once the concrete has been poured, you’ll need to let it cure for several days. The curing time will vary depending on the type of concrete you used. Once the concrete has cured, you can remove the forms and start to finish the stairs. The finishing process may include adding a surface treatment, such as paint or stain.
