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© 2026 cohaga AG · All Rights Reserved · St. Gallen, Switzerland · Imprint745,765 companies indexed · Last updated: today
DirectoryConstruction & ArchitectureCivil EngineeringSt. GallenWilli Bau AG
Willi Bau AG Logo
Verified· 3 sourcesTrust Score
Summary

About the company

Willi Bau AG is a construction company offering building and civil engineering works, demolition and system waterproofing. The company combines demolition, excavation and builder services and delivers projects for residential, commercial and public clients, including core drilling and concrete repair.

AI-generated
Offering

Products & services

Industry:Civil Engineering
✓ Offered8
Civil engineering
Excavation, excavation support and dewatering; new construction and renovation of sewer systems and service lines; forecourts, parking lots, composite paving areas, paving works and minor road construction works.
Building construction
Additions and conversions of single-family and multi-family houses, new construction of single-family houses, construction of multi-family houses and residential developments, retaining walls, staircases and ground slabs.
Demolition work
Strip-outs of buildings, demolition of entire houses and buildings, dismantling of structural components, integrated hazardous substance remediation, as well as reinstatement and renaturalisation measures.
Commercial construction
Construction of business premises, company headquarters and production halls, renovations of representative building components, renewal of installations, adaptation works, as well as maintenance and facility services.
Public sector construction
New construction of business premises and workshops, schools and municipal buildings, transformer stations, pipeline construction, engineering structures, roundabout and bridge construction, water engineering works, and on-site interventions in case of pipe bursts.
Client work
Minor alterations in the bathroom, kitchen and throughout the house, repairs of damage and water ingress, plastering and stucco work, concrete cosmetic repairs, as well as drainage and spring/water intake structures.
System waterproofing
Waterproofing of building components, remediation of water ingress and moisture, installation of white and yellow tanking systems, and complete system waterproofing for new builds.
Core drilling
Penetrations for water, electrical and heating services, drilling up to 450 mm, cutting out and separating concrete, and a fully equipped service vehicle.
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4.4/5

Willi Bau AG

Trust & reputation

ranQ Trust Score of Willi Bau AG: 4.4 out of 5.0

Trust Score4.4/ 5.0

Very high

x

Data basis 96% · As of October 2026

Willi Bau AG scores 82.2 out of 100 points in the Reputation area of the ranQ Trust Score. This area carries 42% of the weighting.
x
CriterionValueWeight
  • Review quality: The average rating across all connected sources, smoothed against the industry mean. So 5.0 stars from three reviews do not outrank 4.7 from three hundred.83.924%
  • Review volume: The number of reviews across all sources. The scale is logarithmic: the first reviews count the most, and the maximum is reached at 50 reviews.73.510%
  • Review recency: The age of the most recent review. Two-year-old reviews deliberately sit in the middle, because that is normal for Swiss SMEs. Only after three years without a new voice does the value drop markedly.88.08%
Willi Bau AG scores 89.1 out of 100 points in the Substance area of the ranQ Trust Score. This area carries 28% of the weighting.
x
CriterionValueWeight
  • Establishment: Years since founding or brand launch, logarithmic. The maximum is reached at 15 years.100.012%
  • Company size: The headcount band, researched by ranQ or stated by the company. It is scored in steps rather than by head count, because the data only provides bands.90.07%
Willi Bau AG scores 85.0 out of 100 points in the Identity area of the ranQ Trust Score. This area carries 22% of the weighting.
x
CriterionValueWeight
  • Verification: Official register entry (commercial register with UID or professional-body record, 55 points), confirmed domain (20 points) and confirmed ranQ profile (up to 25 points, depending on completeness).85.022%
Willi Bau AG scores 42.9 out of 100 points in the Visibility area of the ranQ Trust Score. This area carries 8% of the weighting.
x
CriterionValueWeight
  • Website authority: Ahrefs' Domain Rating measures, on a scale of 0 to 100, how strongly a website is linked from other websites. For Swiss SMEs the range up to 40 is typical; the maximum is reached at 35.42.94%
  • Media authority: No data point — the criterion is taken out of the weighting and does not lower the score.—4%
Qualifications+0.00

Willi Bau AG reaches a ranQ Trust Score of 4.4 out of 5.0 — rated «Very high». The rating draws, among other things, on 4.9 out of 5 stars from 17 customer reviews. The data basis is 96%, so the score is backed by part of the criteria. As of October 2026.

The Trust Score cannot be bought and is calculated from publicly verifiable data.

Reviews

Aggregated rating

Aggregated rating
4.9
of 5

Aggregated from 17 reviews across all connected sources

Sources
GGoogle4.917
★TrustpilotSoon
PProvenExpertSoon

Further sources are added continuously and factored into the ranQ Rating.

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Comparisons

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Location

Burgstrasse 63
9000 St. Gallen
Opening hours
Mon
07:00 - 12:00, 13:00 - 17:30
Tue
07:00 - 12:00, 13:00 - 17:30
Wed
07:00 - 12:00, 13:00 - 17:30
Thu
07:00 - 12:00, 13:00 - 17:30
Fri
07:00 - 12:00, 13:00 - 16:30
Sat
Closed
Sun
Closed

At a glance

Legal form
Branch
UID
CHE-319.710.163
Founded
2001 · 25 years
Last commercial register change
March 16, 2018
Employees
51 to 100
Legal form: Graded by liability and disclosure. The weight is kept small: a sole proprietorship is not a dubious company, it is just liable differently.
76.0
6%
  • Branch offices: Branch offices linked in the commercial register. Having none is normal and costs no points.70.03%
    • Full methodology

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