Screeding is a common technique used to level uneven floors, ensuring a smooth and even surface for flooring materials such as tiles, carpet, or wood. Here’s a step-by-step guide on how you can screed uneven floors.
What is Screeding?
Screeding involves applying a layer of material (usually a mixture of cement, sand, or specialised screed compounds) over a subfloor to create a level surface. It is typically used when the existing floor has dips, bumps, or slopes that need correcting before laying the final flooring.
When Should You Screed A Floor?
You should consider screeding if:
- The subfloor has noticeable dips or bumps.
- There is a slope in the floor you want to correct.
- The floor needs to be prepared for new flooring.
- The surface requires strengthening or smoothing for improved durability.
Types of Screed
Traditional Sand & Cement Screed:
- A mixture of sand and cement.
- Commonly used for general levelling, offering strength and durability.
Flowing or Liquid Screed:
- Made with anhydrite (calcium sulphate) or cement and poured as a liquid.
- Ideal for large areas and underfloor heating, as it flows into all gaps and provides excellent coverage.
- Faster drying and less labour-intensive compared to traditional screeds.
Self Levelling Compound:
- A fine, fast-setting material used for minor floor imperfections.
- Suitable for small dips or uneven areas rather than significant levelling.
- Often used as a finishing layer on top of traditional screeds for ultra-smooth results.
How to Screed an Uneven Floor: A Guide
Materials Needed:
- Screed mixture (sand and cement, flowing screed, or self-levelling compound)
- Trowel
- Spirit level
- Screeding board
- Mixing bucket or pump (for liquid screed)
- Floor primer (if required by the screed manufacturer)
Step 1: Prepare the Subfloor:
- Clean the floor: Remove any dirt, dust, debris, or grease to ensure the screed adheres properly.
- Check the existing floor level: Use a spirit level to identify the areas that need filling or levelling.
- Prime the floor (if needed): Some screed compounds require a primer to help them bond to the subfloor.
Step 2: Mix the Screed:
- Traditional screed: Mix sand and cement in the correct ratio (typically 3 or 4 parts sand to 1 part cement).
- Flowing screed: Use a pump for larger areas, mixing according to the manufacturer’s instructions.
- Self-levelling screed: Mix as per instructions, ensuring the right consistency for easy spreading.
Step 3: Apply the Screed:
- Lay the screed: Start at one corner of the room, spreading the screed mix evenly across the floor using a trowel or a screeding board.
- Ensure level: Use a spirit level and screeding board to flatten the screed and ensure a consistent level across the entire surface.
- Work quickly: Screed can dry fast, so aim to work efficiently and smooth out any imperfections as you go.
Step 4: Allow to Dry:
- Curing time: Traditional screeds may take up to a week to dry, while liquid and self-levelling screeds can set within a few hours or days.
- Avoid walking on the screed until it is fully cured, especially if laying tiles or flooring directly on top.
Step 5: Final Levelling (if needed):
- For a perfectly smooth finish, apply a self-levelling compound after the main screed has cured to fill in any small imperfections or to add a fine top layer.
