Peat

Summary

Peat is an accumulation of partially decayed vegetation formed in waterlogged, acidic, low-oxygen conditions; soils made mostly of peat are histosols. It compresses under minimal weight and cannot be compacted into stable support, so peat is removed or bypassed under foundations, roads, and slabs.

Cols

Image

Histosol: soil made mostly of peat
Pt: USCS group for highly organic soils
Peatland: wetland storing carbon in peat
Bog iron: iron ore formed in peat wetlands

History and demand

Sourcing

2025 world peat production was about 17 million tonnes; Finland about 2.5 million, Canada and Latvia about 2.0 million each, Belarus, Russia, and Sweden about 1.8 million each, Germany about 830,000 (USGS 2026 estimates)
2016 world production was about 26.1 million tonnes; Ireland has since ended peat harvesting

Demand trend

Falling for fuel: Bord na Móna stopped all peat harvesting in 2021; selling peat for burning was banned in Ireland in 2022; Chile banned peat extraction in April 2024
Horticulture persists: the Netherlands imported about 2.16 billion kg of peat in 2020; peat-free alternatives are gaining ground (the UK set a 90 percent peat-free horticulture target in 2010)

Properties

Mechanical

Compressibility: poor consolidation properties; easily compressed under minimal weight; difficult to build structures, roads, and railways on (the West Highland railway across Rannoch Moor floated on a mattress of tree roots, brushwood, earth, and ash)

Standards

Test methods

ASTM D2487: soil classification (Pt group)

Uses in buildings

Building elements

Landscaping and Planting: horticultural growing medium
Spread and Continuous Footings, Slab on Grade: not a bearing material; encountered as compressible subgrade that is removed or bypassed

Pros and cons

Pros

Burns as fuel when dried
Used as a horticultural growing medium

Cons

Highly compressible and settles
Regrows only about 1 mm per year
Drained peatland emits about 4 percent of human-made greenhouse gases (excluding fires)

Sustainability

Embodied carbon

Peatlands store up to 550 Gt of carbon, about 42 percent of all soil carbon; peat fires are a major emission source

Sources

Wikipedia: Peat, https://en.wikipedia.org/wiki/Peat
Wikipedia: Unified Soil Classification System, https://en.wikipedia.org/wiki/Unified_Soil_Classification_System
Wikimedia Commons: Peat (49302157252).jpg, photo by David Stanley (CC BY 2.0), https://commons.wikimedia.org/wiki/File:Peat_(49302157252).jpg
USGS: Mineral Commodity Summaries 2026, peat, https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-peat.pdf