Formula version: 1.1.0. This methodology describes a pedestrian material estimator. It does not select pavement structure, base or bedding depth, slope, drainage, soil remediation, compaction, frost protection, paver thickness, permeability design, or vehicular capacity.
Paved area and boundaries
Included regions and exclusions are axis-aligned rectangles in one shared coordinate system. Net paved area is the geometric union of included regions minus the union of exclusions:
net area = area(union of included regions minus union of exclusions)
Overlapping included regions contribute area once, and overlapping exclusions are not subtracted twice. The boundary engine keeps exposed outer edges and internal exclusion edges distinct with geometry-derived stable IDs. The user selects only the segments receiving purchased manufactured restraint; unselected edges may be an existing wall/curb or another manually handled condition and remain unpurchased in this takeoff.
Installed modules and borders
For a single-size paver with actual face length L, face width W, and installed joints Jx and Jy, the grid pitches are L + Jx and W + Jy. A simple aligned rectangle uses whole grid counts large enough to cover each direction. Composed orthogonal geometry enumerates the global grid cells that intersect the paved region.
Full units, cut units, and geometric cut area remain visible. A grid cell whose required paved portion is disconnected cannot automatically be treated as one physical paver; it requires another unit or explicit manual review. The engine does not claim that cut offcuts are nested into other cells.
A generated simple-rectangle border is deducted from the field count, with rectangle corners counted once. Other border layouts may use a user-entered unit count whose corner treatment is already included, but that measured line is deliberately additive: the field takeoff continues to cover the full net paved surface because this release does not infer an arbitrary installed border footprint.
For a documented modular set, exact installed set coverage replaces single-unit grid counting. Set contingency is applied before whole-set rounding, and pallets round only after the set quantity is known. Individual size counts are shown only when the selected product documents exact package composition and laying pattern.
Reconcile the pattern sketch with purchase demand
The single-size purchase engine counts an aligned grid, regardless of the selected drawing pattern. Its “Full grid units” and “Cut grid units” describe that purchase grid. The separate placement sketch generates grid, running-bond or compatible basket-weave positions and selects a horizontal baseline from four candidate offsets to avoid small edge pieces. It does not replace the purchase-grid count or transfer its cut positions into the order. Basket-weave compatibility checks belong to the drawing; a missing or rejected drawing does not validate or change the purchase list.
For an illustrative 4 × 2 ft rectangle, 8 × 4 in units, zero joints, no border or exclusions: the purchase grid has 6 columns × 6 rows = 36 whole units. The running-bond sketch at the selected zero offset has 33 whole positions plus 6 half-unit edge positions = 39 drawn source-unit positions, with no assumed reuse between the halves. A selected 25% paver contingency, zero broken-unit contingency and 10 units/package give 36 × 1.25 = 45 adjusted unit equivalents, then ceil(45/10) = 5 packages / 50 units. Package surplus is 5 units above adjusted demand; capacity exceeds the drawn 39 positions by 11 units, which is a different comparison. These dimensions and percentages are arithmetic illustrations, not product or reserve recommendations.
Pattern selection alone leaves that order unchanged. Review the drawn source positions against the purchase grid and your actual cut/reuse plan before choosing reserve or ordering. For field reconciliation and avoiding duplicate allowances, see the overage guide.
Layers and purchase conversions
For user-supplied compacted depth D, compacted layer volume is net layer area × D. A user-entered loose-order factor converts compacted volume to order volume. Supplier density may then convert the order volume to mass, while a labeled bag yield may convert it to whole bags.
Compacted volume, loose order volume, mass, and bag count are alternative representations of the same layer requirement; they are not added together. Density, yield, order factor, and depth belong to the selected material and remain visible assumptions rather than hidden defaults.
An excavation volume, when shown, is a geometric reference from user-entered area and depth. It does not approve an excavation depth, side support, disposal allowance, or safe digging method.
Joint material, edging, and spikes
Joint-product packages equal the eligible paved area, adjusted by the separately entered joint-material contingency, divided by the selected product's documented coverage and rounded up. Package surplus is reported as coverage surplus and is not labelled installation waste.
Edge-restraint pieces are rounded independently for each contiguous selected segment by default. Cross-segment offcut reuse is allowed only when the user confirms the selected product can be cut and reused that way.
With a user-entered maximum spike interval S, a straight restrained segment of length E uses ceil(E ÷ S) + 1 spike positions when both endpoints require spikes. Shared-corner deduplication is permitted only under an explicit geometry and product rule; no universal spike spacing is supplied.
Fabric rolls
Optional fabric uses a user-entered roll width, roll length, side overlap, and end overlap. Effective lane advance is roll width − side overlap, which must be positive. Whole lanes cover the selected width, required lane lengths include entered end overlaps, and those cut lengths are allocated against whole rolls.
Fabric is a quantity output only. The calculator does not decide whether geotextile is suitable, select its specification, or provide geosynthetic engineering advice.
Separate loss and surplus categories
Geometric cut loss, broken-unit contingency, loose-order factor, package surplus, and pallet surplus are five separate concepts. They remain separate in results and saved project data so one category is not silently counted as another.
Limitations
The first release supports pedestrian rectangles, L-shapes represented by non-overlapping orthogonal rectangles, rectangular exclusions, single-size units, exact manufacturer-defined set coverage, orthogonal border courses, user-specified layers, joint products, selected edge restraints, spikes, optional fabric, and package or pallet rounding.
It excludes arbitrary polygons, curved or diagonal layouts, automatic cut nesting, automatic pavement or drainage design, permeable reservoir design, soil and frost decisions, vehicle loading, and product compatibility decisions. Selected product instructions, supplier data, field conditions, and local requirements control.
Primary scope references are the CMHA interlocking pavement guide, CMHA edge-restraint guide, and CMHA geosynthetics guide. They provide terminology and design context; they do not make this estimator a design or approval tool.
Corrections can be reported to feedback@materialnest.com.
Bounded stock optimization
Stock allocation applies to selected edge-restraint cuts when cross-segment offcut reuse is confirmed, and to fabric lane cuts including entered overlaps. Without edge reuse, restraint pieces round independently for each selected boundary. The allocator retains its best valid small-search plan at the work limit and labels it heuristic; larger work can use deterministic placement or a labelled conservative one-cut-per-stock fallback. This does not optimize paver cutting patterns: paver packages, pallets, layer purchases, and reserves use their separate coverage and rounding rules. Saved quantities remain unchanged until recalculation.