TryBuildCalcMortar-Set Patio Calculator (Rigid Installation, on a Slab)
Size your mortar-set patio materials instantly.
🕒 Last updated: September 22, 2026
Inputs
Mortar-Set mortars pavers/flagstone onto a concrete slab (new or existing) — no separate edge restraint or fabric needed.
Concrete Slab
ℹ️Mortaring onto an existing, sound concrete patio skips new slab material and cost entirely.
ℹ️4 in is standard for a residential patio slab; step up for heavier loads like a hot tub or very heavy furniture.
ℹ️Optional — confirm with a local contractor/engineer for anything beyond a straightforward residential slab.
Mortar Setting Bed
ℹ️1.25 in nominal is the commonly-cited standard mortar setting bed thickness.
Pavers
ℹ️Pedestrian-only thicknesses — no 80mm vehicular-rated tier, since a patio never carries vehicle loads.
ℹ️Running bond has the lowest cutting waste and works with any paver shape; herringbone and basket weave are designed for roughly 2:1 rectangular pavers.
Joint Fill
ℹ️Mortared joints run wider than sand-set joints.
Cost
Pavers Needed
908
4 x 8 in (Standard Brick), Running Bond (Stretcher) — lowest waste
New Slab Needed
2.489 yd³
4" thick, new pour
Patio Area
192
sq ft (17.84 m²) — 16 x 12 ft
Installation Method: Mortar-Set (Rigid, on a Slab) — Surface: Concrete Pavers
Concrete Slab
4" thick, new pour
Theoretical volume: 2.37 cu yd
Order volume (incl. 5% waste): 2.489 cu yd
Mortar Setting Bed
1.25" nominal thickness
Order volume (incl. 10% waste): 22 cu ft
Bags needed: 37 (~80 lb each)
Pavers
4 x 8 in (Standard Brick)
Order area (incl. 5% waste): 201.6 sq ft
Pavers: 908
Joint Fill
Mortar / grout, 0.5" wide
Volume (incl. 10% waste): 7.79 cu ft
Bags needed: 13 (~80 lb each)
Assumptions Used
Rectangular residential patio, pedestrian loads only (never vehicular). Mortar-Set: a new poured concrete slab (5% waste), a troweled mortar setting bed (10% waste), and mortared/grouted joints (10% waste) — no edge restraint or geotextile fabric needed, since the slab itself contains the assembly. 4 x 8 in (Standard Brick) concrete pavers are quantified by the order area (footprint plus your chosen Running Bond (Stretcher) — lowest waste pattern's own cut waste) divided by each paver's own footprint. This calculator computes material quantities only — it does not verify subgrade compaction adequacy, drainage slope, local frost-depth requirements, or structural design for an unusual soil or loading condition.
Approximate results for planning only. Verify with a professional.
Diagram simplified for clarity (not to scale) — layer band heights reflect relative thickness, not exact scale.
Looking for the verification checklist, reference tables, tips, or common mistakes?See the complete Patio/Paver Materials Calculator.
Mortar-Set: a rigid system built on a concrete slab
Mortar-Set (rigid) installation mortars pavers or flagstone directly onto a concrete slab — either a newly poured slab or an existing, sound concrete patio — with a troweled mortar setting bed and mortared/grouted joints instead of loose joint sand. Because the slab itself contains the assembly at its edges, no separate edge restraint or geotextile fabric is needed.
This page defaults to a 16 x 12 ft patio (192 sq ft) with a new 4 in concrete slab — CMHA's own cited standard thickness for a residential patio slab. Edit the inputs above, including switching to 'Mortar Onto an Existing Concrete Patio/Slab' if you already have a sound slab to build on.
Patio/Paver Materials Calculator Formula: How Is It Determined?
Your patio area, installation method, and surface material combine into a full material takeoff, with a different formula path for each branch of the sand-set/mortar-set x pavers/flagstone matrix.
Step 1 — Patio Area
Area = Length x Width
Entered directly as a single rectangle.
Step 2a — Sand-Set: Base Course
Base Volume = Area x Base Depth
Order Volume = Base Volume x (1 + 15% compaction) x (1 + 8% waste)
Base depth is a pedestrian-only figure (4-6 in) per ICPI/CMHA patio guidance — materially shallower than a driveway's vehicular-load base.
Step 2b — Mortar-Set: Concrete Slab
Slab Volume = Area x Slab Thickness (skipped entirely if mortaring onto an EXISTING slab)
Order Volume = Slab Volume x (1 + 5% waste)
A new slab is 4-6 in thick per CMHA mortar-set guidance; an existing, sound concrete patio can be used directly with no new slab material.
Step 3 — Bedding Course or Mortar Setting Bed
Sand-Set: Bedding Volume = Area x Bedding Depth x (1 + 10% waste)
Mortar-Set: Mortar Bed Volume = Area x Mortar Bed Depth x (1 + 10% waste), then Bags = Order Volume / Bag Yield
Bedding sand/stone dust is installed loose (no compaction allowance); a mortar bed is troweled to a nominal thickness and bagged in whole units.
Step 4a — Concrete Pavers
Order Area = Area x (1 + Layout Pattern Waste %)
Paver Count = Order Area / Paver Unit Area
Layout pattern waste ranges 5-13% depending on cut geometry — the same formula this site's Paver Driveway Calculator uses, since the underlying cutting-waste geometry doesn't change for pedestrian loads.
Step 4b — Natural Flagstone
Order Area = Area x (1 + 10% cutting/breakage waste)
Tons = Order Area x Thickness x Stone Density / 2000
Flagstone is quantified by WEIGHT, not a fabricated per-unit count — coverage-per-ton is derived directly from the stone's own density and thickness.
Step 5 — Joint Fill
Rectangular units: Volume per sq ft = 144 x (1/W + 1/L) x Joint Width x Joint Depth
Flagstone: Volume = Area x Joint Area Fraction x Joint Depth
Concrete pavers use exact rectangular joint geometry; flagstone's irregular joints are approximated as a fraction of surface area that scales with joint width (a standard simplification for irregular-stone jointing takeoffs).
Step 6 — Cost
Line Cost = Order Quantity (bags/tons/sheets/bars/sq ft, as actually purchased) x Unit Price
Total = Sum of every line item relevant to your selected installation method
Every cost line is priced off the actual PURCHASED unit — never the bare theoretical volume — and only line items relevant to your selected Sand-Set/Mortar-Set branch are included in the total.
Worked Example
This example walks through your current inputs above, using the same steps as the Formula section.
Input Values Used
| Input | Value |
|---|---|
| Patio Size | 16 x 12 ft (192 sq ft) |
| Installation Method | Mortar-Set |
| Surface Material | 4 x 8 in (Standard Brick), Running Bond (Stretcher) — lowest waste |
Step 2b — Concrete Slab
| Calculation | Result |
|---|---|
| 192 sq ft x 4/12 ft, +5% waste | 2.489 cu yd |
Step 3 — Mortar Setting Bed
| Calculation | Result |
|---|---|
| 192 sq ft x 1.25/12 ft, +10% waste | 22 cu ft (37 bags) |
Step 4a — Pavers
| Calculation | Result |
|---|---|
| 201.6 sq ft / 0.2222 sq ft per paver | 908 pavers |
Step 5 — Joint Fill
| Calculation | Result |
|---|---|
| 7.08 cu ft, +10% waste | 7.79 cu ft (13 bags) |
Figures above are rounded for display; the real quantities are always calculated from full, unrounded values.
Therefore, a 192 sq ft (16 x 12 ft) Mortar-Set patio using 908 4 x 8 in (Standard Brick) pavers needs 2.489 cu yd of new slab concrete and 37 bags of mortar bed mix, plus 13 bags of joint fill.