Glossary term

Underpinning

Structural work that extends or strengthens an existing foundation, often needed when excavating below its original level.

Updated 2026-08-30

BASEMENT ATLAS

Sources and evidence

Method & sources →

Source types stay separate: technical and authority-adjacent sources support rules and risk topics, while project sources document practical experience.

1 technical/authority sourcesUpdated 2026-08-30

Technical checkpoints

1existing foundation depth

2load-bearing support and stability

3crack width and pattern

4future inspection and maintenance

5existing and planned floor build-up

6drain and sewer levels

Relevant guides

Basement underpinning

Basement underpinning. Start by documenting existing foundation depth, load-bearing support and stability and crack width and pattern. The purpose is to understand the building condition and constraints before choosing products, finishes or a work sequence.

Basement excavation and floor lowering

Basement excavation and floor lowering. Start by documenting existing foundation depth, load-bearing support and stability and existing and planned floor build-up. The purpose is to understand the building condition and constraints before choosing products, finishes or a work sequence.

Problem scenarios

Relevant real cases

Editorial caseUnderpinning & foundation strengtheningModerator reviewed

Sjellonlund, Denmark – floor lowering and underpinning as a partial contract

A case with a clear handover: demolition, excavation and underpinning were completed professionally before the client continued the floor build-up.

Denmark · Sjellonlund

Editorial caseUnderpinning & foundation strengtheningModerator reviewed

Amager, Denmark – excavation, sectional underpinning and complete basement renovation

A first-party case showing excavation and numbered underpinning stages under an existing house, followed by a complete basement rebuild.

Denmark · Amager

Editorial caseBasement excavation & lowering the floor

Charlottenlund: a basement lowered 120 cm with new garden access

A low basement in Charlottenlund, Denmark, was lowered by about 120 cm and given a larger opening towards the garden. The structural and masonry phase produced an unfinished w

Denmark · Charlottenlund

BASEMENT ATLAS

Continue in the same topic

Related guides, problems, checklists, cases and technical terms from the same knowledge area.

GuideBasement excavation and floor lowering→GuideBasement underpinning→GuideBasement ceiling height→ScenarioCracks appear after basement excavation→CaseAmager, Denmark – excavation, sectional underpinning and complete basement renovation→CaseSjellonlund, Denmark – floor lowering and underpinning as a partial contract→CaseVirum, Denmark – complete basement renovation from excavation to finished rooms→ProblemCracks or movement→ProblemLow basement / lower the floor→ChecklistBasement excavation quote checklist→

Evidence & moderation

Editorial policy →

Eurocode 7: Geotechnical designEuropean Commission Joint Research Centre↗

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