Source: https://guthlabs.ai/docs/instruments/tile-flooring-calculator/mechanism/

instrument mechanism / verified-clean

# Tile & Flooring Calculator mechanism

The inspectable method record for Tile & Flooring Calculator, kept separate from implementation and qualification.

Status: **VERIFIED_CLEAN**Lifecycle: **verified-clean**

## Model scope

The core area, waste, tile-count, and box-count arithmetic is standard under the stated unit assumptions. Approval requires an explicit diagonal-layout rule, a defined percentage representation, consistent handling of box coverage versus tiles_per_box, and a grout-estimate formula with its required inputs. The honest label should state that 10% and 15% waste values are rules of thumb and that actual waste depends on cuts, room geometry, tile size, and layout.

- The tile-count formula is standard if waste% means a percentage converted to a decimal: ceil(room_area × (1 + waste_percent/100) / tile_area). The notation 1+waste% is ambiguous in implementation.

- The stated diagonal-layout adjustment is not present in the formula. It is only implied through a default waste factor of 15%, so the layout toggle must explicitly map straight to 10% and diagonal to 15%, unless the user overrides waste.

- The specification accepts box coverage, but the formula requires tiles_per_box. A conversion is missing: tiles_per_box = box_coverage / tile_area, with compatible units.

- Grout estimate is listed as an output but has no formula or required inputs such as grout-joint width, tile thickness, grout depth, coverage rate, or grout packaging.

- The formula does not state whether room dimensions and tile dimensions may use different units or how conversions are performed.

## Units and conventions

- All area quantities in each calculation must use the same area unit before division.

- waste_percent is interpreted as percentage points: 10 means 10%, so the multiplier is 1 + 10/100 = 1.10.

- Tile area is calculated as tile_length × tile_width after converting both dimensions to the same length unit.

- If box coverage is used instead of tiles_per_box, box coverage must use the same area unit as room area and tile area.

- ceil is applied to tile count before dividing by tiles per box, as specified.

- The diagonal default is assumed to be 15% and the straight-layout default 10% for these test vectors.

## Inspectable vector

One of 4 source-bound review vectors:

````
{
  "inputs": {
    "room_length_ft": 12,
    "room_width_ft": 10,
    "tile_length_in": 12,
    "tile_width_in": 12,
    "waste_percent": 10,
    "layout": "straight",
    "tiles_per_box": 10
  },
  "expected_outputs": {
    "room_area_sq_ft": 120,
    "tile_area_sq_ft": 1,
    "tiles": 132,
    "boxes": 14
  },
  "working": "1. Room area = 12 ft × 10 ft = 120 ft². 2. Tile area = 12 in × 12 in = 1 ft × 1 ft = 1 ft². 3. Waste-adjusted area = 120 × (1 + 10/100) = 120 × 1.10 = 132 ft². 4. Tiles = ceil(132 / 1) = ceil(132) = 132. 5. Boxes = ceil(132 / 10) = ceil(13.2) = 14."
}
````

## Failure boundary

**BREAK_CLAIMED** · SELF_FLAGGED

The specification permits a zero tile area that causes division by zero, does not define validation for zero room area, and provides no formula or required inputs for the grout estimate.

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/tile-flooring-calculator/>)[03**Implementation**](<https://guthlabs.ai/docs/instruments/tile-flooring-calculator/implementation/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/tile-flooring-calculator/qualification/>)

## Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

- `VERIFIED_LEDGER.json`

- `evidence-tranche4/tranche4-results.json`

- `BOUNDARY_HAZARD_CATALOG.json`