The following all applies to a flat root cement slab that has slight ponding
You will need to apply the cement in 2 phases, 1- the slurry 2- the concrete mix
When i say by volume, what is meant is that 1 cup of cement gets x cups of aggregate, no weight involved
1- The bonding slurry
- As thin as you can provided it is “Continuous” and “Worked into the surface”
- thicker is bad not good
- The concrete layer needs to be added IMMEDIATELY after applying the slurry, within lets say 10 minutes in warm weather
- consistency should be thicker than emulsion paint
2- The concrete mix
The bare minimum height, for something that is not a foot path, and is not expected to hold any weight is 2.5CM ! cement cant be less than that, it will break and create problems later on !
Consistency = Thick enough to hold its shape
3- The proportions
1- Cement + SBR slurry
Equal amounts of all 3 by volume
1 SBR
1 Watter
1 Cement
The cement mix by volume…
1 cement
3 sand
1 stone dust
2–3 teaspoons per cup of cement, (5–8% of cement volume)
Things to watch out for
Substrate condition
- Slab is sound (no loose flakes)
- No dust when rubbed by hand
- No oil, paint, curing compound, or algae
- Cracks addressed (at least cleaned / chased)
Moisture state (SSD)
- Surface is damp but not shiny
- No standing water in depressions
- Water does not bead up
Bonding slurry
- Freshly mixed
- Thin, paint-like
- Fully covers area
- Worked into pores
- No puddles or ridges
Slurry Finger test
- Sticky
- Leaves residue on finger
- Still dark
Screed mix consistency
- Semi-dry
- Holds shape when squeezed
- No water sheen
- Does not crumble