Specialist personnel with a plan and survey trolley on a construction site in front of homes under construction.

Ordnance assessment for apartment buildings

Before an apartment building is constructed, the excavation, retaining works and foundation locations are checked against existing ordnance assessments. FONTANA-EOD agrees the investigation areas, depths and access needed with the client and design team. This also includes early earthworks for crane foundations, access routes and temporary services. Send the building, retaining works and utility plans with depths and existing reports so that investigations can be agreed before the next construction phase.

Before excavation

Define the excavation and depth.

Before foundation work

Coordinate borehole locations and retaining works.

Before procurement

Specify the scope and reports.

At a glance

Assess the ground works for the apartment building

An ordnance assessment becomes relevant where an apartment building's excavation, basement, underground car park, lift pit, foundations, utility diversions or retaining works disturb areas with unresolved evidence of suspected ordnance. The planned depths, existing services, neighbouring buildings, ground investigation data, access and records needed by site management, the client and subsequent trades all matter. FONTANA-EOD checks these details against existing investigation results and identifies the further investigation required. The assessment follows the actual building, foundation and construction plans, including retaining works, working spaces and temporary ground disturbance. It is not determined simply by the building type or number of dwellings.

Project references

Selected project examples

Hostenbach – apartment building, radar

The scope for “Hostenbach – apartment building, radar” included ground-penetrating radar, specialist ordnance supervision during construction, surveying, documentation and evaluation.

Service period: 2026-03

Service areas:Ordnance specialist supervision of groundworksSurface surveys: GPR, TDEM and magnetometryMethod used in this project: Ground-penetrating radarSetting out and marking survey areasDocumentation and interpretation of survey data

View project details · GPR and limitations · Ordnance specialist supervision of groundworks

The wider housing development

Which adjoining areas may need to be assessed

The building may adjoin plots or infrastructure areas that have already been investigated. Reports and plans are checked to establish which results can be used for the new excavation, retaining works locations and service connections.

Specialist personnel with a plan and survey trolley on a construction site in front of homes under construction.
Housing construction

Housing and infrastructure overview

Housing projects need to consider the excavation, underground parking and infrastructure as well as the building. Investigation areas also include working spaces and service routes outside the building footprint.

Housing and infrastructure development
Specialist personnel with a plan and survey trolley on a construction site in front of homes under construction.
Housing construction

Building plot before construction

Where a plot becomes a defined building project with an excavation, service connections and foundations.

Arrange assessment of a building plot
Specialist personnel with a plan and survey trolley on a construction site in front of homes under construction.
Housing construction

New development and subsequent buildings

Where a development has several construction areas, the infrastructure works and later building phases must be linked clearly in the records.

Coordinate the new development
Specialist personnel with a plan and survey trolley on a construction site in front of homes under construction.
Housing construction

Excavation during ongoing civil engineering works

For forthcoming excavation, the suitability of ordnance surveying during the work is assessed. Access, retaining works and reporting arrangements are agreed accordingly.

Assess the surveying needed during excavation
Specialist personnel with a plan and survey trolley on a construction site in front of homes under construction.
Housing construction

Underground car parks and basements

Basements, ramps, lift pits and deep foundations are key considerations in many apartment building projects.

Assess an underground car park
Specialist personnel with a plan and survey trolley on a construction site in front of homes under construction.
Housing construction

Neighbourhood development

Apartment buildings often form part of larger neighbourhood developments with several construction phases, existing buildings, external works and roads.

Assess the development section
Technical principles

Key terms in apartment building assessment

For an apartment building, the excavation, retaining works, foundations, service connections and temporary working areas are described with their respective depths of ground disturbance.

Suspected hazard

Evidence of suspected ordnance comes from historical sources, traces of past land use, existing reports, regional experience and the planned work. For housing projects, it matters whether that evidence concerns the whole site, particular areas or specific depths.

Intervention depth

Depth is more than a single figure on a section drawing. The excavation formation level, service trench base, borehole, shaft, infiltration trench and deeper foundation sections may call for different investigation approaches on the same site.

Extent of the construction area

The relevant area often extends beyond the future building footprint. Working space, access routes, retaining wall alignments, utility trenches, temporary roads and landscaping may each involve ground disturbance.

Method limitations

Survey methods respond differently to ground conditions, moisture, interfering objects, metal content, the surface and the target object. Investigation records are reliable only when these limitations are understood for the project.

Ground investigation and ordnance assessment

Geotechnical investigation and ordnance assessment should be coordinated in both location and timing. Borehole locations, starting elevations and planned depths help determine the appropriate technical approach.

Excavation and site supervision

Where prior investigation is limited, the suitability of ordnance surveying during excavation is assessed. Each working layer is surveyed and evaluated before controlled removal in stages, supported by visual checks. This sequence is repeated down to the agreed formation level. Before work starts, site management, machine operators and specialist personnel agree the excavation layers, stop signal, authority to give instructions, reporting arrangements and documentation.

Findings assessment

Survey anomalies are assigned for follow-up investigation using their location, survey conditions and technical evaluation. If an unexpected suspicious object is found, work must stop, people must keep their distance and the find must be reported immediately.

Project file

The project records should show what was investigated, which methods were used, where the limitations lie and what site management, the client and following contractors need to do next.

Procurement

Tendering and subcontractor coordination need clear service boundaries, investigation depths, responsibilities, working windows and documentation requirements.

Communication

The design team, site management and civil engineering contractor receive the same current plan showing the investigated areas and depths, survey limitations and any further investigation required. The relevant authorities receive the information they need for their duties.

Decisions before ground works

When a project requires an ordnance assessment

Technical assessment begins as soon as ground works are defined. Bringing the location, depth, construction phase and available documents together early makes it easier to include the investigation in design and procurement.

Planning application and detailed design

The building footprint, basement floors, foundations, retaining works and external works are defined sufficiently to establish a reliable investigation boundary.

Prepare investigation records for design

Excavation and retaining works

Sheet piling, bored piles, soldier pile and lagging walls, slopes and underpinning can significantly change the investigation requirements and access.

Plan the excavation assessment

Underground car parks, basements and shafts

Ramps, lift pits, plant rooms, sumps and basement excavations create local deeper areas with specific investigation requirements.

Have deeper areas assessed

Ground investigation and foundations

Boreholes, probing, piles and wells may require an ordnance assessment of their starting locations before work begins.

Agree borehole positions

General contractor and procurement

Service boundaries, documentation and working windows must be described so that earthworks, retaining works and subsequent trades can be coordinated.

Prepare procurement documents
Phases of a housing project

Assess the apartment building from design to construction

The assessment is coordinated with land acquisition, design, ground investigation, procurement, excavation and report handover. It begins before ground investigation, retaining works design, tendering or earthworks. The corresponding plan revision identifies which ground works are defined sufficiently for physical investigation.

01

Early project concept

At an early stage, only the plot, outline concept and intended use may be known. An initial technical assessment can still be useful where excavation, foundation work or infrastructure works are foreseeable. This helps prevent ordnance issues emerging only after ground investigation dates, purchase decisions or procurement arrangements have been fixed.

02

Land acquisition and due diligence

When land is purchased, a project is taken over or a housing site is developed, the available records, previous use, existing reports and planned ground works all matter. An ordnance assessment can identify unresolved questions early and help include subsequent investigation work in the project budget and programme.

03

Ground conditions and surveying

Geotechnical reports, surveys, terrain models, design levels and proposed borehole locations provide important technical information. Bringing these details together with the evidence of suspected ordnance and the depth of work helps determine whether surveying or specialist supervision is needed before drilling or excavation.

04

Design and approval planning

At this stage, the building footprint, infrastructure, basements, underground car parks, road alignments and utility trenches become more clearly defined. The ordnance assessment should address these actual ground works, construction phases and the records needed by the design team and site management.

05

Tendering and specifications

Before procurement, the service boundaries, investigation depths, areas, documentation and interfaces must be described so that the client, bidders and site management understand the same requirements. Unclear wording often leads to variations, programme difficulties or uncertainty over responsibilities during construction.

06

Site establishment

Access routes, storage areas, crane positions, temporary roads and working spaces may each involve ground disturbance. Leaving them out of the investigation area creates gaps between the assessed area and the parts of the site actually used. Necessary investigations and protective measures are planned before the ground works needed to establish these areas, and before intrusive vegetation clearance, demolition or breaking up surfaces.

07

Earthworks and civil engineering

Excavation, drainage works, utility trenches, formation levels and foundations are critical interfaces with ordnance assessment. Investigated sections, ongoing work, reporting arrangements and documentation must be coordinated so that the project can respond consistently to unexpected findings.

08

Communication of findings

If a suspected object or ordnance find is encountered, an orderly flow of information matters alongside the technical evaluation. Its location, depth and surroundings, the trades affected, contact persons and relevant authorities must be established without speculation.

09

Construction phases and remaining areas

Housing developments are often serviced or built in phases. The records must therefore show which areas have already been assessed to which depths and which remaining areas need to be reviewed for later phases.

10

Subcontractors and subsequent trades

Civil engineering, retaining works, structural construction, utility installation and landscaping need clear investigation records. The documentation should support both the initial decision and subsequent trades by identifying the assessed areas and unresolved follow-up questions.

11

Handover to buyers or operators

For building plots, new developments and apartment buildings, information may later be passed to buyers, operators, property managers or subsequent designers. The investigated areas, depths and service boundaries must be documented clearly for this purpose.

12

Follow-up decision

After the assessment, it must be clear whether further records, an ordnance survey, checks during construction, follow-up investigation of findings or simply documented continuation of the project are appropriate. That next decision is the practical value of the technical assessment.

Starting conditions, investigation and documentation

From suspected ordnance to a documented project decision

A reliable ordnance assessment brings together existing records, available survey methods, the construction sequence and documentation. The result is a traceable basis for the next project decision, rather than an isolated finding.

01

Confined construction area

Apartment buildings are often built on urban or previously affected sites. Restricted access, existing walls and neighbouring buildings affect the investigation conditions.

Assess the construction boundaries
02

Deep basement levels

Underground car parks, basements, lift pits and plant room excavations extend deeper into the ground and may need different methods from shallow external works.

Agree the investigation depth
03

Retaining works and drilling

Bored piles, anchors, beams, sheet piles and underpinning create local deep ground disturbance that must be checked against the evidence of suspected ordnance.

Have the starting locations assessed
05

A finding in an excavation or utility route

Survey anomalies are evaluated and assigned for targeted follow-up investigation. Do not touch, move or continue uncovering an unexpected suspicious object. Stop work in the affected area, leave the immediate vicinity and keep others away without putting yourself at risk. In Germany, notify the police immediately on 110; elsewhere, use the local emergency reporting route. The relevant authorities decide what happens next. Internal reporting must not delay the emergency call.

Plan how findings will be reported
06

Documentation for subsequent trades

Structural contractors, civil engineering contractors, retaining works contractors, specialist designers and the client need a common set of investigation records for the areas concerned.

Agree evidence requirements
Selecting a method

Which assessment suits the housing site?

The appropriate ordnance assessment depends on the available records, surface conditions, interference, depth of work and construction sequence. For housing projects, the method must suit both the programme and the required documentation, as well as being technically feasible.

Two monitors displaying aerial photographs and maps; further aerial photograph printouts lie on the desk.

Historical assessment

Aerial photographs, historical plans and land-use records help define areas of suspected ordnance. They do not replace a physical investigation, but provide an important basis for selecting the method, depth and documentation.

Assess historical documents
Illustration of a person beside a GPR instrument, with schematic waves in a ground section

Near-surface surveying

Ground-penetrating radar, magnetometry or TDEM may provide suitable information, depending on the surface, interfering objects and survey targets. Their suitability depends strongly on the ground conditions and surrounding interference.

Request a technical assessment of the surface survey
Person beside a survey instrument on a construction site; a wheeled excavator with drilling equipment stands behind them.

Investigation at depth and borehole locations

For deep excavations, boreholes, shafts or foundations, we assess whether a suitable surface method can adequately investigate the intended working space. Where coverage is insufficient, additional investigation at depth is planned. The location, planned depth and starting point must be described precisely.

Agree borehole locations and depths
Person with a tablet at the edge of a cordoned-off excavation, with an excavator behind.

Excavation supervision

Where prior investigation is limited, the suitability of ordnance surveying during excavation is assessed. Each working layer is surveyed and evaluated before controlled removal in stages, supported by visual checks. This sequence is repeated down to the agreed formation level. Before work starts, site management, machine operators and specialist personnel agree the excavation layers, stop signal, authority to give instructions, reporting arrangements and documentation.

Assess the surveying needed during excavation
Coordination within a housing project

Who should be involved early in an apartment building project?

Before work begins, design information, ground investigation data, civil engineering works, utilities and investigation records are assigned to the same construction phase and plan revision.

Planning and construction management

The design team and site management need to work from the same site information. The site plan, construction limits, sections, depths, construction phases and existing records are brought together so that decisions are documented, rather than agreed only verbally during a site meeting.

Civil engineering and retaining works

Civil engineering contractors and retaining works designers need clear details of working space, borehole locations, excavation sequence, exclusion areas and possible interruptions. This information should be available before work starts so that it can be included in the programme.

Utility coordination

Utility routes often extend beyond the building footprint and are installed under separate contracts. The ordnance assessment must therefore consider service connections, public utility routes, shafts and crossings alongside the housing site.

Ground conditions and surveying

Surveying and ground investigation provide coordinates, starting elevations and sections. These data are particularly useful for documenting investigation points, boreholes and excavation depths unambiguously.

Communication with clients and buyers

Housing projects often need investigation records later for project files, handovers or communication with buyers. Statements about the investigated areas, depths and service boundaries must therefore be clear from the outset.

Scheduling

Ordnance assessment should not be scheduled as a last-minute addition just before excavation starts. A better approach is to include time for reviewing records, surveying, any necessary supervision and documentation in the construction programme.

Individual sections and remaining areas

A project may contain both investigated areas and areas that have not yet been assessed. The documentation must make that distinction clear so that later earthworks do not inadvertently rely on records that do not cover them.

A finding during the project

If a suspected object is encountered, its location, depth and surroundings, the trades affected, contact persons and relevant authorities all matter. Clear communication arrangements agreed in advance reduce uncertainty during construction.

Documentation linked to the plans

Reports and results should refer to plans, alignments, coordinates, construction phases or site boundaries. This allows them to be used reliably in meetings, procurement and subsequent decisions.

The next technical step

The assessment must establish whether further records, an ordnance survey, borehole assessment, excavation supervision or follow-up work on findings is needed. Providing that clarity is its main value to the project.

Records for the project file and site management

Which documents need to be usable after the ordnance assessment?

Housing project documentation must be clear, tied to specific locations and usable by subsequent teams. It should record the result and explain how the site, depths, construction sequence and interfaces are to be addressed next.

Record the baseline information

The site address, site plan, land parcel, construction area, sections, construction phase and existing requirements provide the initial working basis.

Assess suspected ordnance

Historical records, previous land use, aerial photograph analysis and existing reports are reviewed alongside the planned ground works.

Specify the method and depth

The surface, interfering objects, ground conditions, services, excavation and planned depth determine which assessment is technically appropriate.

Document the result

The investigated areas, survey data, evaluation of findings, photographs and recommendations are recorded for the project. Where objects have actually been exposed or clearance work carried out, the corresponding investigation and clearance records are included.

Plan the next construction steps

The documentation must enable site management, procurement teams, subcontractors and subsequent trades to understand the next step.

Plan how findings will be reported

If suspected objects or ordnance are found, the location, surroundings, contact persons and relevant interfaces are established without delay.

Evidence dossier

Which project information needs to be brought together before work starts?

Housing projects need coordinated investigation work, ground data, construction planning and documentation. A well-prepared project file prevents important information being lost between design, procurement and site management.

Project file

Building and excavation locations

The building footprint, basements, underground parking, ramps, shafts, working spaces and external works are shown as areas of ground disturbance.

Project file

Depth and starting location data

Borehole locations, retaining wall alignments, piled foundations, wells, utility trenches and local deeper areas receive clear location and depth references.

Project file

Construction sequence and responsibilities

The client, project managers, site management, civil engineering, retaining works, structural construction and specialist designers need clear arrangements for exchanging investigation and findings information.

Project file

Investigation records for the construction file

The documentation must identify the areas, methods and depths assessed and the subsequent decisions relevant to the construction sequence.

Project process

From the first records to a planned investigation

The sequence is planned so that ordnance assessment, ground investigation, infrastructure works, civil engineering and documentation follow the same project requirements.

01

Review the project enquiry and documents

The site plan, sections, depths of work, construction phase and existing evidence of suspected ordnance are brought together.

02

Define investigation boundaries

The construction area, route, excavation, borehole locations, working space and external areas are assessed separately according to the ground disturbance involved.

03

Assess suspected ordnance conditions

Historical and technical information is assessed so that the construction sequence is not determined by a blanket assumption.

04

Define the method

Suitable survey or supervision methods are selected according to the surface, interfering objects, ground conditions and depth.

05

Coordinate the work

Dates, access, site safety arrangements, site management and subcontractors are included in the programme.

06

Carry out the investigation

The agreed surveys or investigations during construction are carried out for the specified areas and depths. Their location, conditions and completed scope are recorded.

07

Assess results

Survey data, findings and limitations are evaluated. Working spaces that have not been investigated sufficiently, and any further investigation needed, are identified by location and depth.

08

Document results

The investigated areas, findings, data quality and next steps are recorded clearly for the project file.

Technical detail

Key factors in assessing an apartment building project

The investigation area follows the planned ground works and may extend beyond the building footprint. Working space around the excavation, retaining works, utility diversions, crane positions and temporary roads are recorded by location and depth.

Housing and infrastructure projects need an assessment of the actual ground disturbance: the area, depth, construction phase and required records determine the appropriate approach.

Technical consideration

Working space around the excavation

As well as the future building, slopes, retaining works, working space, ramps, dewatering and temporary construction areas must be considered where they involve earthworks.

Technical consideration

Local deeper areas

Lift pits, sumps, plant room excavations, deeper foundations and underground car park ramps may require a different investigation depth.

Technical consideration

Drilling and retaining works locations

Piles, anchors, soldier pile and lagging walls and underpinning create local ground disturbance. A general area assessment does not replace assessment of these individual ground works.

Technical consideration

Construction in a confined space

A confined construction area, neighbouring buildings and occupied storage areas may restrict access. The timing of the necessary investigations is agreed with site management.

Technical assessment points

What should be clarified before surveying, excavation or drilling?

The areas, planned depths, access, ground conditions and sources of interference are described before the method is selected. The subsequent report records the working space actually investigated and any limitations.

Check point

Surface conditions and access

Vegetation, temporary roads, stored materials, old foundations, fences and confined access routes affect whether a site can be surveyed effectively before excavation or needs a different sequence of work.

Check point

Sources of interference on housing sites

Metal fixtures, reinforcement, old services, scrap, demolition rubble and boundary structures can interfere with survey data and must be considered in the evaluation.

Check point

Depth of work and design level

The excavation formation level, drainage invert, pile starting level, infiltration trench, shaft and utility trench involve different depths. The records must show which ground works the assessment covers.

Check point

Utility and as-built plans

Information on existing services, building connections and public utility routes is needed not only for safety planning; it also informs the survey method, vehicle access and interpretation.

Check point

Construction phases and working windows

Necessary investigations are scheduled before the corresponding ground works. Separate investigation stages are defined for areas that become accessible later. Ordnance surveying during excavation must be technically suitable for the work; exclusion areas, reporting arrangements and the sequence are agreed with site management before material is removed.

Check point

Documentation limits

Every investigation record needs clear details of the assessed area, depth, method and limitations. This keeps its scope clear for later construction phases.

Comparing methods

Why the method must suit the site and the ground works

No single method replaces every other assessment. A reliable decision for a housing project considers the records, survey conditions, depth, access, construction sequence and documentation requirements.

Methods

Aerial-photo analysis

Historical aerial photographs help assess evidence of suspected ordnance and past land use, and prepare investigation areas. They do not show current ground conditions; their findings are therefore checked against current construction and survey data.

Methods

Surface survey

Surveying from the surface requires adequate access and suitable conditions. The working space, sources of interference, survey grid and achievable depth are specified for the construction area. Areas with insufficient coverage are assigned a separate investigation step.

Methods

Ground-penetrating radar

Ground-penetrating radar records reflections at material and structural boundaries and can provide additional information on non-metallic features and layering. Its suitability depends on the ground and surface conditions. A reflection does not unambiguously identify a metal target or ordnance.

Methods

Magnetometry

Suitable for magnetic anomalies in areas with little interference. Metal fences, reinforcement, services and scrap can limit the results.

Methods

TDEM

May be suitable for electrically conductive metal objects where site conditions permit. Its limitations depend on the target size, depth, surrounding interference and survey setup.

Methods

Deep-ground survey

For deeper ground works, the first step is to assess whether a suitable surface method covers the required volume of ground. Where coverage is insufficient, additional investigation at depth is planned for the actual location and required depth.

Methods

Downhole survey

Surveying from investigation boreholes may be considered where the investigation objective is suitable and other methods provide insufficient coverage. Borehole starting points, planned depths, drilling methods and the volume of ground that can be investigated are defined in advance.

Methods

Excavation supervision

The suitability of ordnance surveying during excavation is assessed for the specific work. Each working layer is surveyed and evaluated before controlled excavation proceeds. The results are documented with their location, depth and limitations; simply watching the excavator does not replace a necessary ordnance survey.

Methods

Ordnance recovery

Survey anomalies receive targeted follow-up investigation or exposure. Recovery of confirmed ordnance is coordinated within the permitted scope of work, local responsibilities and documentation requirements. If an unexpected suspicious object is encountered, stopping work, keeping a distance and reporting it immediately take priority.

Project routes

Prepare investigations before civil engineering and retaining works

Ground investigation, foundations and earthworks each need location and depth details and existing investigation results. The scope, methods and records are specified before procurement for the corresponding civil engineering and retaining works.

Project pathway

Review the records before ground investigation

When borehole locations, window sampling or ground investigation are being prepared, the locations, depths and evidence of suspected ordnance should be considered together in advance.

Assess borehole locations in advance
Project pathway

Fit earthworks into the programme

The appropriate investigation method is selected in advance for excavations, utility trenches or ground reduction. Simply watching the excavator does not replace a necessary ordnance survey.

Select the investigation method before earthworks
Project pathway

Evaluate records of suspected ordnance

Before physical investigation, aerial photographs, historical plans and land-use history help define the investigation area and the priority of individual sections.

Review the evidence of suspected ordnance
Project pathway

Prepare evidence for procurement

Tendering and site management need a clear description of the scope, investigation area, depth, documentation and subsequent decisions.

Prepare evidence for procurement
Project pathway

Identify the project region

Regional responsibilities, the project location, federal state and available records may affect which interfaces need early preparation.

Assess the project region
Project pathway

Send a complete project enquiry

The site plan, sections, depths, construction phase, evidence of suspected ordnance and contact details can be sent together to FONTANA-EOD.

Send project documents
Working approach

Hand over results for retaining works, civil engineering and utilities

FONTANA-EOD describes the investigated areas with their plan and depth references. Site management receives the information needed to coordinate the individual trades.

Mark outstanding areas on the site plan

The report and plan show which parts of the building, working spaces and foundation locations were covered. Restricted survey conditions and outstanding investigations are identified. If the design changes, this allows the new ground works to be checked against the existing findings.

Project-specific assessment

The assessment follows the construction objective, depth of work, available records and construction sequence, rather than blanket assumptions.

State method limits

Survey methods are used so that interfering objects, the surface, ground conditions and access are taken into account in the evaluation.

Hand over the report and site plan together

Locations, methods, results and next steps are documented in a form that site management and the client can use.

Inform the project team about outstanding areas

Project managers, designers, civil engineering contractors, the relevant authorities and subsequent trades receive clear information about the area concerned.

Project responsibilities

Who provides which information for the ordnance assessment?

Clear responsibilities reduce delays. The client, designers, site management, specialist contractor, civil engineering contractor and relevant authorities have different tasks but work from the same site information.

Role

Client and project management

They define the project objective, working windows, available records and required documentation. These provide the framework for the technical assessment.

Role

Designers and specialist consultants

They provide site plans, sections, ground investigation data, borehole locations and technical details of the proposed ground works so that the investigation areas can be defined reliably.

Role

Construction and civil engineering contractors

They carry out earthworks, drilling, retaining works or utility trenching and need clear information on work areas, reporting arrangements and documentation.

Role

Competent authorities

In Germany, the ordnance disposal services of the federal states and the locally competent authorities carry out hazard-response and find-management duties. Their involvement is established for the project location; outside Germany, local responsibilities apply.

The local public order authority and, where relevant, building control authority are involved according to their project responsibilities. Requirements, contact persons and reporting arrangements are assigned to the plot, planned ground works and individual construction phases.

Examples of typical project situations

Records, investigation and documentation for housing construction

The working area, planned depth and access are established for each investigation. The results remain tied to the corresponding ground works.

Two people discussing plans at a table beside a vehicle on a construction site.

Investigation records for project participants

Reports, site plans and evaluations are handed over together so that the client and site management can understand the investigated areas and limitations.

Bring the investigation records together
Four people in orange high-visibility vests in front of two excavators on a construction site.
Person with a yellow survey cart on a footpath in front of a hedge.
Identify the project location

Identify the building, neighbouring areas and local requirements

Illustrated map of Germany with location markers on a construction site.

Identify the site and applicable requirements

Before construction, the investigated areas and depths must be clear. Retaining works, civil engineering and utility teams receive the results relevant to their work and information on outstanding areas.

The address, land parcel and excavation plan identify the project. Existing correspondence, file references and contacts are linked to the planned ground works. Neighbouring plots form part of the investigated area only where this is documented.

Technical information

Housing and site development: brochure

From development works to excavation: the brochure shows how to consider ordnance risks early and prepare investigations suited to the planned earthworks.

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Housing and site development: brochure – page 1

German · 8 pages

Questions from housing projects

Frequently asked questions about ordnance assessment for an apartment building

When is an ordnance assessment advisable for an apartment building?

It is advisable where an excavation, basement, underground car park, lift pit, foundations, utility diversions or retaining works disturb the ground and the evidence of suspected ordnance has not been reliably resolved. Assessment is particularly relevant before ground investigation, tendering or the start of excavation.

Which documents are needed for the initial assessment?

Helpful information includes the site plan, building footprint, sections, excavation depth, basement design, retaining works strategy, utility plans, ground investigation data, borehole locations, existing reports, aerial photograph analysis and earthworks programme. Official information and requirements should be included with their dates, complete appendices and the areas to which they apply.

What should be done if a suspicious object is found during earthworks?

If an unexpected suspicious object is found, stop work in the affected area immediately. Do not touch, move or uncover the object further. Leave the immediate area and keep others away without putting yourself at risk. In Germany, notify the police immediately on 110; outside Germany, use the local emergency reporting procedure. The competent authorities determine what happens next. Inform site management and the client; internal reporting must not delay the emergency call.

Which methods may be considered for apartment building projects?

Depending on the project, historical aerial photograph analysis, ground-penetrating radar, magnetometry, TDEM, investigation at depth, downhole surveying or excavation supervision may be relevant. The choice depends on the depth, surface, interfering objects, services and construction sequence.

How are borehole locations for retaining works or ground investigation assessed?

Borehole locations are checked against their position, planned depth, starting elevation, surroundings and evidence of suspected ordnance. Existing investigation results are then checked to establish whether they cover the planned ground works or which additional investigation is necessary and suitable.

Can the assessment take place during excavation?

A suitable approach during construction can be planned where the investigation requirements call for it. It does not automatically replace prior investigations. DGUV distinguishes necessary ordnance surveying during excavation from visual observation alone, which does not meet the current state of the art.

Which investigation records matter to site management and the client?

Important records include investigated areas, depth references, methods used, measurement or survey results, evaluation of findings, photographs and recommendations for subsequent construction. Their form depends on the commission and project phase.

What determines the effort and cost of an ordnance assessment?

The main factors are the area, excavation geometry, depths of work, ground conditions, sources of interference, access, construction phases, existing records, required methods and documentation. Pricing requires details of the planned working spaces and commissioned investigation scope.

Preparing an enquiry

Information needed for a reliable assessment

Precise details of the project location, ground works, depth and construction phase help FONTANA-EOD identify the appropriate next technical step for the housing project.

Site and area

Address, land parcel, site plan, construction boundary, building footprint, routes and affected sections.

Ground disturbance and depth

Excavation, basement, foundations, borehole locations, utilities, shafts, infiltration trenches, excavation depth and construction phase.

Available documents

Aerial photograph analysis, historical plans, utility plans, ground investigation data, sections, requirements and existing reports.

Documentation objective

Procurement, site management, project records, communication with buyers, ground investigation or a follow-up decision.

Submit project details together

Please send the available documents as fully as possible. An early design can also be assessed if the location, planned ground works, depth, construction phase and required records are clear.

Telephone

+49 (0) 6843 - 999 499 7

Email

info@fontana-eod.de

Project documents

Site plan, depth, construction phase, suspicion indicators

Contacts

Site management, design or project management

Have project documents assessed
Project details

Information that helps us assess the apartment building project

Send the site plan and sections showing the planned ground works, depths and corresponding construction phase. Identify existing investigations and the next scheduled date.

Describe the location clearly

The address, land parcel, plan extract and coordinates help identify the investigation area without further enquiries. Larger projects should also identify construction phases, alignments or work area numbers.

Specify proposed formation levels and depths

Planned depths are essential for the technical assessment. Sections, excavation formation levels, drainage inverts, borehole profiles and foundation depths provide a much stronger basis than a general project description.

State the construction phase

An enquiry before ground investigation, before tendering or shortly before excavation starts leads to different next steps. Please state the project stage clearly.

Include the existing records

Aerial photograph analysis, geotechnical reports, utility plans, historical plans, existing site records and requirements should be sent together so that individual details are not taken out of context.

Identify the project contacts

Project managers, designers, site managers, civil engineering contractors and the client hold different information. Clear contact arrangements make it easier to coordinate dates and resolve questions.

Define the purpose of the documentation

Before submitting an enquiry, state whether the records are needed for procurement, site management, ground investigation, communication with buyers or a subsequent technical decision.

Project enquiry

Have your project assessed

Whether historical aerial photograph analysis, explosive ordnance surveying, surface surveying using GPR, magnetometry or TDEM, deep-ground surveys, downhole surveys, excavation supervision, area clearance or ordnance recovery is needed depends on the location, ground disturbance, depth, ground and existing documents. An early ordnance assessment provides clarity for tendering, programming, occupational safety and construction.

FONTANA-EOD combines its Section 7 SprengG licence, specialists holding Section 20 SprengG certificates of competence, suitable survey and clearance methods, and traceable documentation. Send the site plan, depth of ground disturbance, construction phase and existing documents for an initial technical assessment.