Post mix concrete is designed for setting posts and is quite simple to use. It typically requires minimal mixing, primarily involving adding water directly to the hole where the post is placed. However, mixing it correctly is important for a solid set.
Here's a step-by-step guide:
- Dig the Hole: Make sure the hole is wide and deep enough to accommodate the post and the concrete. The diameter should be roughly three times the width of the post.
- Position the Post: Place the post in the center of the hole. Use braces or supports to hold it plumb (perfectly vertical).
- Pour in the Dry Mix: Pour the post mix concrete directly into the hole around the post, filling it to within a few inches of the top.
- Add Water: Slowly add water to the dry mix. The key is to avoid adding too much. Typically, you'll add water until the mix is thoroughly saturated. The concrete should begin to stiffen up, but it should not be runny.
- Mix Briefly (Optional but recommended): While many post mix concretes are designed to set with minimal mixing, stirring the mixture in the hole with a shovel can help ensure that the water is evenly distributed and that there are no dry pockets.
- Check Plumb and Brace: Re-check that the post is still plumb. Adjust as necessary and ensure bracing is secure.
- Allow to Set: Let the concrete set according to the manufacturer's instructions (usually printed on the bag). This may take anywhere from 30 minutes to several hours, depending on the product and weather conditions. Avoid disturbing the post during this time.
- Backfill (Optional): Once the concrete is fully set, you can backfill the remaining space with soil.
Important Considerations:
- Read the Manufacturer's Instructions: Always refer to the instructions on the specific post mix concrete product you are using. Different brands may have slightly different recommendations.
- Safety: Wear gloves and eye protection when handling concrete. Avoid getting the mix on your skin.
- Weather: Avoid pouring concrete in freezing temperatures, as this can weaken the final set.
- Amount of Water: Too much water will weaken the concrete. Aim for a damp, not soupy, consistency.
While the reference text discusses a 3-2-1 ratio for mixing concrete, this applies to creating your own concrete mix from scratch using sand, gravel, and cement. Post mix concrete is pre-blended and doesn't require you to add these components. It simplifies the process by requiring only water.
