Segmental retaining walls (SRWs) combine concrete block units, soil, drainage, and sometimes geosynthetic reinforcement. A calculator can help organize early material quantities, but it cannot decide whether a wall is acceptable for a site. The governing facts come from the selected SRW product, manufacturer instructions, current CMHA guidance, ASTM connection data, geotechnical information, local code, AHJ policy, utility locates, excavation-safety controls, and qualified structural or geotechnical review.
The ToolGrit retaining-wall app deliberately labels block counts, geogrid rows, drainage stone, base gravel, pipe, and fabric as local prompts. The purpose of this guide is to keep those prompts in the right lane: useful for estimating conversations, not a substitute for project-specific wall analysis or construction authorization.
What the Material Screen Does
The app counts wall blocks and cap blocks from the entered height, length, face dimensions, and pallet row. It also produces local prompts for geogrid area, drainage stone, drain pipe, filter fabric, base gravel, trench width, and trench depth. Those rows can help a contractor or owner frame supplier questions and compare rough scenarios.
The app does not model block weight, shear keys, pins, lips, batter geometry, cap and corner details, steps, curves, tiers, terraces, guardrails, fences, water features, product limits, or supplier packaging. Add those project-specific items before ordering material or setting expectations.
Retaining Wall Geogrid & Block Calculator
Calculate block quantity, geogrid layers, drainage stone, and base trench dimensions for segmental retaining walls.
Height, Soil, and Surcharge Review
Wall height definitions matter. Exposed height, total height, design height, buried depth, tiered walls, and slopes can change the review path. CMHA source material notes that height, soil, surcharge, and geometry influence SRW behavior, and local requirements may set review thresholds differently.
Soil rows in the app are placeholders. They do not classify retained soil, reinforced fill, or foundation soil. Groundwater, frost, expansive soil, settlement, compaction, poor drainage, nearby slopes, utilities, driveways, buildings, pools, guardrails, and construction equipment can all change what qualified review is needed.
Geogrid and Product Data
Geogrid prompts are not reinforcement selection. Final reinforcement depends on the SRW unit, geogrid product, connection strength, pullout, creep, installation damage, durability, layer elevation, embedment length, compaction, drainage, surcharge, and global stability. ASTM D6638 is a source pointer for connection testing context, not proof that a local app row matches a product system.
Before using a geogrid quantity, collect manufacturer SRW unit data, compatible geogrid data, connection and pullout information, long-term strength reductions, installation instructions, and project specification requirements. A source-aware app can list the gaps, but it cannot close them.
Drainage, Utilities, and Excavation
Drainage and base rows are quantity prompts. The real site still needs drainage outlet review, surface-water control, pipe material and slope, filter fabric selection, cleanouts, erosion protection, frost and groundwater review, stormwater-discharge limits, and manufacturer details.
Excavation around a retaining wall can expose workers and property to cave-in, struck-by, access, utility, traffic, and spoil-placement hazards. Use state one-call requirements, private utility locating where needed, OSHA or state excavation rules, competent-person inspection, protective systems, access planning, and site-specific safety controls before digging.