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Structural Demolition Calculator
Calculate load transfer identification, temporary support positions, demolition sequence planning, and debris chute requirements for structural demolition projects.
Ground floor footprint area
Total floors including ground
Overall building height
Number of load-bearing walls per floor
Leave blank for automatic calculation
Leave blank for auto (buildings >2 floors)
Your quoted disposal rate
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How We Calculate This
This calculator helps plan structural demolition by estimating debris quantities, identifying load transfer points, determining temporary support needs, and generating a top-down demolition sequence following the principles of BS 6187:2011 (Code of Practice for full and partial demolition). BS 6187 covers method, sequence, temporary structural support and exclusion zones — it does not publish debris-quantity figures, so the tonnage estimate below is calibrated separately against published waste data.
Debris estimation
Total building volume × fill factor (the proportion of the envelope that is solid material) × material density gives the debris weight. The fill factors are indicative solid-fraction estimates — masonry 0.10, mixed 0.11, steel frame 0.12, concrete frame 0.16, timber frame 0.22 — chosen so the result lands within published residential demolition waste-generation rates: roughly 300–660 kg/m² of floor area for masonry, 800–1,370 kg/m² for reinforced concrete and 195–725 kg/m² for timber (ScienceDirect, “Demolition Waste — an overview”). They are planning estimates only — always confirm actual arisings via a pre-demolition audit or Site Waste Management Plan.
Load transfer analysis
Load transfer points are identified at each load-bearing wall × each floor level. Temporary support must be provided wherever demolition creates unsupported loads. The number of temporary supports is typically 50% of load transfer points, as some elements can be demolished in sequence.
Demolition sequence
The sequence follows BS 6187 principles: soft strip first, hazardous materials next, then top-down structural demolition from roof level to foundations.
Frequently Asked Questions
A demolition method statement is a detailed document required under CDM 2015 (Construction Design and Management Regulations) that describes how the demolition will be carried out safely. It covers the sequence of operations, temporary support arrangements, exclusion zones, plant and equipment, waste management, and emergency procedures. A structural engineer must review the method statement for any structural demolition.
Top-down demolition is the standard approach because it maintains the stability of the remaining structure at all times. The roof and upper floors are removed first, progressively reducing the load on the structure below. This prevents uncontrolled collapse. The only exception is controlled explosive demolition, which requires specialist planning and licensing.
As a rule of thumb a debris chute is used once materials would otherwise have to be dropped from height — typically buildings over about 2 storeys (roughly 6m) — to transfer demolition waste to skips at ground level. This is good practice rather than a fixed numeric trigger: the Work at Height Regulations 2005 require you to prevent objects falling and to avoid throwing or tipping materials where it could cause injury, but they set no specific storey threshold. Chutes are typically built from interlocking sections of heavy-duty plastic or steel, and the calculator sizes the chute as the drop height plus around 2m of clearance.
Temporary support (shoring, propping, or bracing) is required wherever the demolition sequence creates unsupported elements. This includes floor slabs after supporting walls are removed, freestanding walls that lose lateral support, and any structure that becomes unstable during the demolition sequence. A structural engineer must design the temporary works.
In England, demolition of a building over 50m³ requires prior notification to the local authority under Section 80 of the Building Act 1984. Planning permission is not usually required for demolition alone, but is needed if the site is in a Conservation Area (where demolition needs Conservation Area Consent), if the building is Listed, or if there are specific planning conditions.
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Last updated: March 2026
Verified against UK standards · estimates only, confirm with your supplier.