Landscaping Materials Calculator — Turf, Topsoil & Gravel

Landscaping Materials Guide

What should I know about Coverage and Depth Rates?

Material calculations: volume (m³) = area (m²) × depth (m). Weight = volume × bulk density. Common bulk densities: topsoil: 1.0-1.2 tonnes/m³ (loose). Sharp sand: 1.6 tonnes/m³. Gravel/shingle: 1.4-1.6 tonnes/m³. Bark chippings: 0.3-0.4 tonnes/m³ (very light). Slate chippings: 1.6-1.8 tonnes/m³. MOT Type 1: 2.0 tonnes/m³ compacted. A 40m² gravel path at 50mm: 40 × 0.05 = 2.0m³ × 1.5 tonnes/m³ = 3 tonnes. At approximately 3 bulk bags per tonne: approximately 9 bulk bags. Add 10-15% waste for edges, uneven ground, and settling, which is a sensible margin to build into any materials order.

What do I need to know about Lawn Installation?

Turf preparation: rotavate or dig over to 100-150mm depth. Remove all weeds, stones, and debris — once turf is laid, weeds are permanent problems. Apply topsoil (minimum 100mm for healthy roots — 150mm preferred). Rake level. Roll or firm surface. Topsoil quality: screened topsoil with good structure. Avoid heavy clay or waterlogged topsoil. Turf laying: lay parallel to longest boundary. Stagger joints (brick bond pattern). Never lay in heat or frost. Keep well-watered for the first 4-6 weeks — critical for the roots to establish properly, since new turf that dries out can die before it ever takes hold.

What do I need to know about Gravel and Bark Installation?

Gravel path or driveway: excavate to 100-150mm below desired surface level. Compact existing sub-base or add MOT Type 1 to 100mm compacted depth. Landscape fabric (weed membrane): prevents weed growth through gravel but allows drainage. Critical step — gravel without membrane is a weed nightmare within 1-2 seasons. Apply decorative gravel to 40-50mm depth. Edge restraint (metal or plastic edging): keeps gravel contained and prevents spread onto lawn or borders. Bark chippings: around trees and in planting beds, both suppressing weeds and retaining soil moisture as they slowly break down.

What should I know about Ordering and Delivery?

Bulk bags (also called jumbo bags, 1 tonne bags, or IBC bags): typically 850-900kg, approximately 0.5m³. Standard delivery truck fits 2-4 bulk bags. Access: bulk bag delivery requires a lorry with a grab crane — check access width (minimum 3.5m typically needed). Loose tipper delivery: most economical for large quantities (5+ tonnes). No bags to dispose of. Requires a large flat area for tipping — cannot tip directly into narrow paths or raised beds. Small order: many builders merchants sell smaller bagged quantities for projects that don't justify a full bulk delivery.