Guide
How Much Extra Screed Mix Should You Buy?
Screed reserve should follow measured area, average thickness, floor geometry and product data. Extra bags cannot compensate for an unsuitable thickness or weak base.
Plan extra screed mix after measuring the floor and its thickness map. Uneven zones, complex geometry and losses during mixing and placing can increase the requirement, but there is no universal reserve percentage. Start with the system and the product’s own coverage.
What the requirement contains
- Floor area that will actually receive the screed.
- Average thickness rather than the deepest point of one hollow.
- Dry mix consumption stated for the selected product and thickness.
- Losses while carrying, mixing, filling corners and working around guides or services.
- Differences between the preliminary floor map and the real substrate.
Avoid overbuying and shortages
Split the room into zones and check deep areas separately. Applying the maximum depth everywhere can overstate the purchase, while assuming a perfect plane can leave too little mix. Add the allowance before rounding up to full bags.
Reserve does not fix a wrong system
Extra bags do not make an excessive layer safe or a weak base stable. Choose the screed construction and permitted thickness first, then calculate the material and allowance.
Use the calculator as a planning tool
Enter room dimensions, average thickness, allowance and dry-mix data in the screed calculator. It returns an estimated volume and weight; compare that result with the actual floor map and the package information before ordering.
Store the reserve correctly
Keep dry mix only under the conditions allowed by the manufacturer. Damp, caked or damaged bags should not be counted as reliable reserve material.
Frequently asked questions
What percentage of screed reserve should I use?
There is no universal percentage. Geometry, thickness variation, product packaging and handling determine the allowance.
Should I add reserve before or after rounding bags?
Calculate the material and allowance first, then round up to whole bags and compare with the product packaging.
Do wall edges need extra thickness?
Include any real design or level changes in the measured floor map rather than adding a generic amount everywhere.
Why was the mix short when the area was correct?
Average thickness, local hollows, losses and product coverage may differ from the preliminary estimate.