Concrete parging is important in protecting your home’s foundation from weathering and damage. Parging is a concrete mixture that is applied as a protective coating over concrete foundation walls and other structures. It acts as a barrier against water, provides insulation, and enhances the aesthetic look of the property.
Over time, parging can develop cracks, chips, or stains that require repair work. Properly repairing concrete parging is essential to maintaining the integrity and longevity of your foundation.
Assessing The Damage
The first step is to carefully inspect the parging to determine what type of repair is needed. Look for cracks, loose or flaking areas, water damage, or mold growth. Take notes on the location and severity of each issue. Next, use a flathead screwdriver or chisel to test how deeply the damage goes.
Minor surface cracks may only need filling, while holes or large cracks may require patching. Finally, consider how widespread the damage is. Isolated cracks can likely be repaired, but severely cracked or delaminated parging may need replacing.
Preparing The Surface
With the damage assessment complete, it is time for surface preparation. Start by power washing the entire wall to remove dirt, mold, and debris. For repair areas, use a wire brush or scraper to remove any loose parging down to the solid concrete. This prepares a stable surface to which the new parging can adhere. Fill and sand any cracks or holes in the concrete so they are level with the surrounding area. Let the surface fully dry before proceeding.
Selecting Materials
Quality parging materials are key. Look for a pre-blended parging mix formulated for foundations. Dry mixes require the addition of water, while some come premixed and ready to use. Also, concrete bonding agents, joint compounds, or mortar should be picked up to fill any gaps. Wearing gas-proof construction gloves and goggles is recommended when handling materials.
Application
Using a small trowel or putty knife, apply the bonding agent to the prepared wall surface using a brushing motion. Let it become tacky. Then mix the parging according to package instructions, usually a powder-to-water ratio, until thick yet smooth and lump-free. Apply a 1/8-1/4 inch layer with the trowel, pressing firmly so it bonds well. Smooth it with the trowel edge. Fill all holes and cracks, then smooth again. Let sections fully dry before moving to the next area.
Finishing And Curing
Once dry, use an abrasive block or sandpaper to smooth any rough spots. A spray bottle of water helps reveal unevenness. For a textured finish, use a wood float, sponge, or texture roller while wet. Allow for a full cure, about five days, to reach maximum strength. During this time, gently mist the new parging a few times daily with a pump sprayer. Proper curing prevents cracking.
Maintenance And Repairs
Inspect the parging annually for signs of weathering or new damage. Power wash as needed using gentle pressure. Reapply sealer every 2-3 years or as indicated. Minor hairline cracks can be filled with elastomeric or hydraulic cement. Larger areas may need re-parging. Consult a professional for extensive foundation wall repairs.
How Long Does It Take To Repair Concrete Parging?
The time it takes to repair concrete parging varies depending on the size of the area and the number of coats needed.
- Inspection and surface prep: 1-2 hours
- Bonding agent application: 30 minutes or less
- Applying the first coat: 1-2 hours for a medium-sized area
- Finishing the surface: 30 minutes once dry
- Curing before light use: 5-7 days
- Full curing before exposure: 2-4 weeks
Safety Precautions When Repairing Concrete Parging
- Wear Protective Gear: This includes gloves, eye protection like goggles, and a dust mask if cutting or sanding concrete. Parging materials can irritate skin and eyes.
- Work In A Well-Ventilated Area: Mixing the dry parging ingredients creates dust that should not be breathed in. Work outside or open windows/doors for ventilation.
- Avoid Contact With Skin And Eyes: The alkaline compounds in cement-based parging can cause chemical burns. Wear gloves and be careful not to rub your eyes with dusty hands.
- Use Caution With Power Tools: Scrapping or sanding concrete creates silica dust that requires a respirator for health safety. Guard against flying debris from impact tools.
- Lift With Care: Bags of dry mix and buckets of wet parging are heavy and should be lifted properly to avoid strains. Get assistance for large/heavy items.
- Store Chemicals Safely: Keep parging compound and bonding agents out of reach of children and pets. Follow all product instructions and disposal directions carefully.
- Watch Expiration Dates: Using expired parging materials can lead to application issues or potential toxicity risks over time. Dispose of it properly.
Conclusion
Properly repairing concrete parging requires time and effort but ensures your home’s foundation remains protected. Following best practices for inspection, preparation, application, and curing leads to a job well done. Some advance planning is needed due to curing periods. With the right repair approach, your parging’s longevity is restored.
