Compliance

UK guidance for planning, drainage and building control.

This app provides general UK guidance and material estimates only. It is not legal, planning, engineering or building-control advice. Always confirm requirements with your local planning authority, building control, utility providers, manufacturers or qualified professionals.

Front gardens & impermeable surfaces

Surfaces over 5m² in front gardens that use impermeable materials may require planning permission unless surface water drains to a permeable area (lawn, border, gravel) or to a soakaway.

Decking

Decking over 300mm high, or covering more than 50% of the garden, commonly requires planning permission.

Fences & walls

Fences next to a highway over 1m typically need permission. Elsewhere, fences over 2m typically need permission.

Trees & TPOs

Excavation near established trees may affect roots. Check for Tree Preservation Orders and conservation area status before digging.

Underground services

Always undertake an underground services check before excavation, especially for fence posts, drainage trenches and bases. Consider a CAT scanner survey.

Retaining walls

Retaining walls over 1m typically require professional structural advice and may need building control approval.

Outbuildings & garden rooms

Common permitted development limits include height (2.5m within 2m of a boundary) and coverage (50% of curtilage). Confirm locally.

Active compliance checks

Planning check: front garden surfaces over 5m² using impermeable materials may require planning permission unless water drains to a permeable area.
Decking over 300mm high or covering more than 50% of the garden may require planning permission.
Total garden coverage exceeds 50% — planning permission may be required for the deck.
Fences next to a highway over 1m tall typically require planning permission.
Fences over 2m tall typically require planning permission.
TPO / conservation area check recommended — excavation near tree roots may need consent.
Underground services check recommended before excavation. Use a CAT scanner or contact utility providers.
Retaining walls over 1m typically require professional structural advice and may need building control approval.
Garden rooms within 2m of a boundary commonly need a maximum height of 2.5m for permitted development.
Planter load exceeds the typical imposed-load limit for this location — consult a structural engineer.
Distributed load is above 2.5 kN/m² — have the supporting structure checked before installing.
Creosote-treated reclaimed sleepers are illegal for domestic/edible beds and leach carcinogens into soil.
Ground-contact timber must be Use Class 4 (UC4) treated, or it rots at the soil line in 3–5 years.
Edible beds should use a food-safe LDPE/HDPE liner — avoid PVC (phthalates).
Planter is too shallow for the chosen planting — roots won't have enough depth.
Sleeper beds over 600 mm tall behave like retaining walls — add posts/bracing or tie-backs.
Tall, narrow planter (height:base over 3:1) can topple — widen the base, add ballast or anchor it.
A masonry planter on/against a boundary wall can trigger the Party Wall Act 1996.
Planters/raised platforms over 2 m high (1 m near a highway) may need planning permission.