According to the provided reference regarding modified sand and cement screeds, they can technically go up to whatever thickness you would like.
However, it is important to understand the practical considerations when dealing with significant depths.
Practical Depth Considerations for Modified Screed
While modified sand and cement screeds offer flexibility in thickness, the reference highlights a point where excessive depth becomes impractical or requires alternative methods:
- Theoretical Maximum: Modified sand and cement screeds can technically reach whatever thickness you would like.
- Practical Threshold: You would question applying screed at depths starting to get up to 150mm, 200mm.
- Alternative Method: At these greater depths (150mm, 200mm, and beyond), you would typically use void formers, such as insulation, and then apply the screed on top.
This suggests that while there isn't a hard maximum dictated by the material itself for modified screeds, conventional building practices and material efficiency lead to the use of void formers for depths exceeding 150mm-200mm rather than filling the entire depth with screed.
Summary of Depth Considerations
| Screed Type | Theoretical Max Depth | Practical Limit (Before questioning / using void formers) | Method Beyond Practical Limit |
|---|---|---|---|
| Modified Sand and Cement Screed | Up to whatever thickness you would like | Approximately 150mm - 200mm | Use void formers (e.g., insulation) under screed |
This approach using void formers helps to reduce material costs, weight, and potentially drying times for very deep sections compared to using screed alone for the full depth.
