Technical map of the Regionalverband Saarbrücken with Saarbrücken marked for explosive ordnance assessments and surveys by FONTANA-EOD

Explosive ordnance surveys in Saarbrücken before excavation and retaining works

Are you planning new construction, demolition or new utility networks in Saarbrücken? For the ordnance assessment, we need the location and depth of the planned ground works and the existing reports. FONTANA-EOD agrees the investigations required with you and documents their results within the agreed scope.

Construction area

Show the excavation, retaining structures and connections on the plan.

Existing assets

Identify known structures, neighbouring buildings and obstacles.

Construction sections

Distinguish accessible areas before and after demolition.

Assess the construction project

What belongs in the investigation plan for an infill building plot?

The Saarbrücken vacant building plot register shows possible areas for development within the built-up area. For the investigation of your project, also describe the excavation, retaining structures, working space and building connections with their depths. One of our own local project examples is downhole magnetometry at the DB transformer station or maintenance facility, lot 3 (BS-264). Information on borehole and deep-ground surveys helps prepare corresponding ground interventions. The register and reference commission do not replace investigation evidence relating to a particular property.

Project references

Selected project examples

Project site

Connect the site with the specific construction task

Outline and coat of arms of Saarland on a map, with a safety helmet, tablet, notebook and pen alongside.

Link Saarbrücken’s planning notes to your own project

The vacant building plot register supports the search for areas for development within the built-up area. The plan at Mecklenburgring refers ordnance clarification to further detailed planning. Your work site needs its own information and results together with the actual ground interventions. Being in a particular district or being shown as a vacant plot does not replace this property-specific preparation.

Ensheim, Brebach-Fechingen and Güdingen also form part of the city. For enquiries from Völklingen, Sulzbach/Saar, Friedrichsthal, Quierschied or Kleinblittersdorf, the respective municipality and project address are identified. Saarbrücken is Saarland’s state capital and part of the Regionalverband Saarbrücken. Its location on the French border does not automatically extend the German procedural framework to a project abroad. City-centre, railway and commercial locations are assessed using actual use and planned earthworks. The headquarters in Gersheim coordinates your specialist enquiry; this does not imply a local branch.

Local context

Building sites and planned ground interventions in Saarbrücken

Searching for building sites and specific ground interventions

The state capital’s vacant building plot register provides information about possible areas for development within the built-up area. An ordnance assessment also needs the specific ground intervention: where will the excavation and retaining structures be, which building connections will be renewed and which preparatory works already disturb the ground? This information must be evident in the site and ground intervention plans.

The planning note at Mecklenburgring

In the development plan “Südlich Mecklenburgring 74 & 76” (statutory version dated 12 December 2024), the city refers clarification of the ordnance question to further detailed planning. The plan identifies an enquiry to the specialist authority or clarification by a commissioned specialist contractor as the options. For a project within this defined area, you should keep the information received and, where applicable, an investigation report available together with the current ground intervention plan.

The individual work site within the city

Projects in Alt-Saarbrücken, St. Johann, Malstatt, Burbach or Dudweiler may have very different records available. Being in a particular district establishes neither suspicion of ordnance nor an all-clear. Historical indications, earlier investigations and current plans are brought together for the work site concerned.

The air raid of 5 October 1944 affected Malstatt, Burbach and Alt-Saarbrücken, among other areas. The city’s historical records document damage to housing and infrastructure and later artillery effects. For today’s works, former buildings, rubble removal, filling and reconstruction must be assigned to the specific volume of ground using the records available. A construction project on a historic railway or industrial site or near the border thus receives its own specialist assessment. General city history is not used to infer ordnance contamination of an individual property.

Working together

Distinguish the tasks of client, designers and specialist contractor

Client and operator

The project owner describes the project and provides the existing records. The operator adds requirements for use, access and timing. A coordinating contact brings the information together; everyone involved performs their respective assigned tasks. Before commissioning, it is clearly recorded which information is missing, who will obtain it and which decision the result is intended to inform.

Planning and construction management

The specialist designers describe areas, depths, construction methods and changes. Site management coordinates the planned sequence with the construction contractors and agreed specialist works. Results are assigned to the respective intervention. A technical plan change is communicated early enough for its effect on the survey task to be assessed before construction. Organisational construction stage boundaries remain distinguishable from technical survey boundaries.

Specialist company and competent bodies

The private explosive ordnance specialist carries out the agreed investigation and documentation scope. Official requirements and decisions are clarified with the competent authorities concerned. The documents needed for a particular procedure depend on the location and project. The technical report describes the specialist service performed; its conclusions are not presented unchecked as general authorisation for further groundworks or as an authority's decision.

Investigation task

Which specialist task comes next?

Select methods for each depth and task

Specialist planning considers the excavation, retaining structures, foundations and connections with their different geometries. Existing results are compared with the scope needed. Existing structures and potential interference inform method selection. A result for a near-surface intervention is not transferred to a deep point without checking; the information achievable remains decisive.

Compare suitable specialist services

Link outstanding areas to the further construction sequence

If a necessary investigation cannot be completed in full beforehand, the next approach for the affected area is agreed. Necessary preliminary works receive their own prerequisites. Specialist planning checks suitable services and limitations. Visual observation of excavation alone or a general demolition approval does not replace the ordnance statement needed for the specific ground intervention.

Compare investigation methods
Project types

Prepare excavation, demolition and connections with the appropriate specialist service

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

Relate existing findings to the work site

Historical records and earlier reports are read with current property and ground intervention plans. It must be clarified which areas and depths were actually covered. Indications from surrounding areas can support preparation but do not replace assignment to your own project. Missing maps or unclear boundaries are clarified specifically before results are adopted.

Identify the report version used with its date and appendices. If a plan is missing, the affected area remains identified as unresolved. An investigation of neighbouring property may provide indications but is assessed according to its actual limits. The information still needed for an additional excavation is determined separately. This prevents a brief summary from an earlier commission from inadvertently becoming evidence for other areas.

Relate existing reports to the ground disturbance
Two people with a tablet beside a marked construction area; plans lie in the foreground.

Coordinate the investigation with existing structures and demolition

Buildings, paved areas and structures in the ground can influence access or measurement conditions. State what will remain and which preparatory ground interventions are planned. The specialist services needed are linked to this sequence. An area accessible only later remains identifiable as an outstanding task; its treatment is not assumed solely from general demolition planning.

State which old basements or foundations will remain and which ground interventions already form part of demolition. The investigation needed is coordinated with these works. Ground removal may create a different working level; its elevation is recorded for the next investigation. A general demolition date is therefore insufficient to plan specialist services. The sequence of actual planned ground interventions and the areas they make accessible is needed.

Compare specialist services
Illustration: two people review plans and documents at a table beside a construction vehicle.

Assign results to the excavation and ancillary works

Documentation shows the scope actually treated and its limitations. For retaining structures, foundations and connections, the information needed in each case is checked. Additional or deeper ground interventions are compared separately. Site management receives complete reports and maps so that results from a brief project summary are not transferred to volumes of ground not covered.

A handover distinguishes the excavation investigation from point-specific statements for retaining structures or foundations. Identify the associated reports and drawings together. Limitations, interference and uninvestigated areas are also part of the records for the next construction phase. If a later change occurs, the affected volume of ground is identified first. The specialist assessment can then reuse existing results specifically or determine the supplementation needed.

Document findings and their limitations
Preparation

Prepare the scope and commission together

Establish what needs to be known before commissioning the work

First establish which decision the commission needs to support. Is the task an initial assessment of existing documents, an investigation of a specific area or examination of an anomaly that has already been assessed? These tasks require different evidence. A general wish for safety does not define an investigation that can be carried out. The enquiry therefore specifies the groundworks, location, depth and available findings. Suitable specialist work and the required reporting are then agreed on that basis.

Define the specialist task

Coordinate preparatory work with the investigation

Required access and survey conditions are clarified before the site visit. This may include keeping areas clear, obtaining service information and coordinating with other trades. The method and site determine which preparations are actually needed. Changes to the surface or additional groundworks are not undertaken unilaterally simply to prepare for a survey. Their sequence is agreed with the specialist designers and responsible parties.

Clarify preparatory work in the programme

Agree a clear scope and schedule

A sound workflow distinguishes work already clarified technically from outstanding prerequisites. If an area will be accessible only in part, commissioning must take this into account. Handover and assessment of results also need time in the construction sequence. An enquiry therefore does not imply a blanket commitment on dates or cost. Specific coordination connects the described scope with access, documents, execution conditions and the date by which a decision is needed.

Discuss the scope and schedule
Tasks at the site

Ground works and access in built-up surroundings

01

Infill plot between existing buildings

When building on an infill plot, ground works outside the new foundation slab must also be considered. Include retaining structures, working space, utility connections and any exploratory ground investigations on the site plan. For each ground intervention, check whether existing reports cover the area and depth concerned.

Draw deeper individual structures and working spaces with their actual base levels. The new building footprint alone often does not fully describe these ground interventions. For changed retaining structures, the investigation information needed is clarified before the elements are installed. Information about neighbouring buildings and their known foundations supports coordination of specialist planning; the construction engineering responsibilities of the designers involved remain unchanged.

02

Demolition before new construction

An existing building or paved yard may limit access for investigation. Describe which areas can be reached before demolition and which only afterwards. Coordinate investigation of these areas with demolition. Areas not yet investigated remain marked accordingly.

An initially inaccessible remaining area receives its own reference in the investigation plan. Once access is established, the actual surface and remaining structures are compared with assumed conditions. Deviations are clarified before further specialist work. Site management can thus see which investigation is already available and which task is intended only after demolition.

03

Utilities in public road space

Building connections and utility networks may extend beyond the building plot itself. Draw the proposed trenches, chambers and transfer points, including their depths. Coordinate investigation of the construction section with those responsible for traffic management and utility operations. Their respective responsibilities remain unchanged.

Also communicate a shifted route or additional connection pit. Available information on existing utilities and the interventions actually planned are brought together with the utility operator. The investigation receives the corresponding section and depth reference. If another contractor makes the connection, it needs the same current results documentation for its working area. Separate procurement does not alter the volume of ground that needs specialist consideration.

04

Neighbouring buildings and site access

Vehicle access, material storage and working space influence when an area can be investigated. Existing structures and metal sources of interference must be considered in method selection. Identify known obstacles in the enquiry so they can be included in investigation planning.

Project documents

Documents that establish the next step

Add other ground interventions to the building footprint

Working space, retaining structures and utility connections may extend beyond the future building. Enter these areas with location and depth on the same plan. Preparatory ground investigations are also considered. The specialist service needed can then address the actual scope of works rather than relying on a building outline drawing that does not yet show these ancillary works.

Where area clearance or other clearance work has actually been commissioned, a clearance log records the areas treated, location and depth references, approach and results. The report and drawings document the scope and outstanding tasks. Subsequent site management receives these records with the current ground intervention plans. Any necessary recovery task is addressed within the technical and authority framework agreed for it.

Describe access in built-up surroundings specifically

Neighbouring buildings, vehicle access and material storage can affect when each area is available. Describe known obstacles and planned changes. Investigation planning depends on the actual conditions at the intended time. The existence of general vehicle access to the property does not yet demonstrate that all necessary working areas are sufficiently accessible and usable for the specialist service.

Construction sequence

Coordinate investigation and construction sections

Start the enquiry with the complete ground intervention plans

Send the current site plan showing the excavation, retaining structures and connections, together with existing reports and appendices. Mark demolition and areas with restricted access. The initial discussion clarifies available findings and further needs. Outstanding information is also recorded before a specific investigation is agreed on an incomplete spatial basis.

Identify the decision needed: is the initial investigation to be planned before demolition, a deep retaining point clarified or an additional connection prepared? Existing records are linked to this task. Missing information about base levels, access or structures is requested specifically. When defining the quotation, it remains identifiable which preliminary work is usable and which specialist work is still intended to be commissioned.

Compare again after demolition and plan changes

Compare the next work step with the documented investigation scope. Changed working levels, shifted construction boundaries and additional connection trenches are clearly shown. Applicable results remain usable and supplementary tasks are identified. Site management receives the current plans and complete records so that the next work can be prepared on a traceable basis.

If site management or the contractor changes, the report version and associated drawings are clearly identified. The handover also includes outstanding parts of the site and their intended next treatment step. A connection shifted later is communicated with location and depth. The specialist assessment can then address the actual change while results already applicable continue to be used transparently.

Method selection

Select methods according to the task and survey conditions

Historical records and aerial photographs

Historical aerial photograph assessment links suitable images to other findings about former use. For an infill plot, the position of previous buildings and today’s excavation are related to one another. Available indications of war damage, reconstruction or later ground changes inform the specialist assessment. An earlier report is read with its maps and boundaries. Outstanding questions determine any supplementation required. The assessment prepares further investigation; it does not replace a necessary technical investigation of the ground.

Understand aerial photograph assessment

Magnetometric survey

Magnetometry measures the magnetic field passively and uses the magnetic effect of ferromagnetic objects. Electrical conductivity alone does not make an object detectable by magnetometry. On an infill plot, remaining foundations, reinforcement and other metal structures are considered potential interference. Actual accessibility also matters in method selection. The result is related to the volume of ground treated. For adjacent retaining works or additional connection trenches, it is checked whether the existing statement fits and which specialist service is still required.

Understand the scope of magnetometry

Electromagnetic methods

Time-domain electromagnetic methods, or TDEM, excite the ground with electromagnetic pulses and assess the response of conductive objects as it decays over time. For the planned excavation, the investigation objective, existing structures and actual measurement conditions are considered. A method is chosen according to the information needed. Different working levels before and after demolition remain identifiable. For results from an earlier construction section, location and documented coverage are compared. Assessment considers interference, evaluates an anomaly technically and records the investigation limitations for further construction planning.

Understand electromagnetic surveying

Ground-penetrating radar

Ground-penetrating radar emits electromagnetic waves and, under suitable conditions, can show structures and reflections in the ground. Water content, ground composition and structures in the ground influence measurement. A reflection does not automatically identify explosive ordnance. For retaining structures and foundations, the question the method is intended to answer is established. The specialist report distinguishes interpretation from further investigation. Old basements, utilities or other structures are considered with the available as-existing information. The spatial statement remains linked to the area measured even if the building outline changes later. A measurement without apparent anomalies is not evidence for arbitrary depths.

GPR and limitations

Deep-ground and downhole surveys

Deeper retaining points or foundations may affect ground below the volume covered by existing investigation results. Specialist planning compares actual intervention depths with the available statements. Where needed, a suitable deep-ground or borehole survey is planned. The starting point and working level are stated clearly; known utilities and structures must be considered. A shifted point is reassigned before execution. The investigation receives its own documentation. A result for the former yard is therefore checked for usability for the new foundation.

Prepare deep interventions

Survey during construction

A necessary ordnance investigation during construction is planned for the actual earthworks. It may combine excavation in layers, specialist exposure and supplementary surveys. Visual observation of ordinary excavation alone is not sufficient as detection. For demolition, it is established which areas must be investigated afterwards and which prerequisites apply. The work sequence considers neighbouring buildings, existing structures and the selected investigation scope. Areas treated and outstanding tasks are documented by section so that subsequent construction can be coordinated with the appropriate specialist information.

Agree the approach during construction
Technical assessment

Assess reports and plan the investigation for the ground intervention

Area reference of earlier reports

Existing aerial photographic assessments and reports are compared with the current property and construction plans. It is particularly important whether a statement relates to the whole work site or only to an earlier section. Missing appendices or unclear location references must be clarified before results are adopted.

Investigation for retaining structures and foundations

A result for near-surface work cannot be transferred to deep retaining works or a foundation without checking. Surface surveys and deep-ground and borehole surveys have different tasks and limitations. Before equipment selection, it is established which areas and depths must be investigated and under which conditions this is possible.

Approach where advance investigation is limited

If the necessary investigation cannot be carried out in full beforehand, the further approach for the affected section must be agreed by specialists. Observing excavation alone is not an equivalent substitute for a necessary ordnance survey during construction. The investigation, any clearance and subsequent construction that are possible depend on the findings and agreed scope of services.

Next steps

Organise records for the next construction section

01

Draw location and ground interventions

Bring together the property, excavation, retaining structures and connections in a clear plan. The initial discussion identifies the project location and information needed.

02

Compare existing reports

Compare reports, including their appendices and limitations, with the current plans. Existing plans, statements and reports are checked for currency, spatial reference, completeness and gaps.

03

Address outstanding historical questions

Missing historical findings are developed through research and aerial photograph assessment within the commission agreed by specialists. Former buildings and recognisable wartime effects are assigned to today’s work site. Results inform planning for the excavation, retaining structures and connections alongside existing reports. An already sufficient knowledge base is taken into account.

04

Clarify access and sequence

Describe investigation areas before and after demolition and possible work steps. Specialist planning selects the suitable method using the investigation objective, intervention depth, ground composition, existing structures and actual measurement conditions. Access and necessary prerequisites are clarified with the responsible parties.

05

Perform the agreed investigation

The agreed survey or specialist investigation during construction is actually carried out. Measurements and observations are assigned to the excavation areas or individual investigation points. The working level used receives its reference elevation. Where work proceeds by section, limitations, interference and areas not yet investigated are documented.

06

Assess and document findings

Specialist assessment evaluates the data collected and findings under the actual measurement conditions. Interference and limits of interpretation are considered. The report and drawings document the specialist assessment with the volume of ground treated and its location, level and depth references. Necessary follow-on investigations or other further tasks are identified for the next construction phase.

07

Pass on the results

Hand over areas investigated, limitations and outstanding tasks to designers and site management. The further construction sequence is coordinated with the responsible parties.

Documentation

Document areas investigated and outstanding tasks

Findings and their scope

The investigation report should show which area was treated with which method and what statements the result allows. Inaccessible areas and remaining limitations stay explicitly identifiable. If the building outline, retaining structure design or depth of a connection changes later, the new intervention is compared with the documented status.

Project responsibilities

The commissioned specialist service is distinct from the authorities’ tasks. In Saarland, hazard response measures when ammunition is found rest with the local police authority or the police; the state ordnance disposal service is involved accordingly. A private investigation report does not replace these responsibilities.

Working approach

How FONTANA-EOD works

Document the agreed specialist service clearly

We assess the planned groundworks against the available documents and their design revision. Before attending site, we agree with you what needs to be investigated, which areas are accessible and what findings are required. If the design or site conditions change, we check whether the agreed scope remains appropriate. The report states what was actually investigated and the limits of the findings. This allows designers and site management to see which findings they can use and where questions remain.

Discuss the investigation task

The task before the equipment

We first establish the investigation objective: which question must it answer? We then select a technically suitable method. The availability of a particular device or experience on a similar neighbouring site is not enough to justify the choice of method on its own.

Keep limitations visible

Inaccessible areas and limited conclusions are identified. They do not disappear into a total area figure. Designers and site management can then decide specifically which areas still need attention and when a suitable survey becomes possible.

Clarify changes before intervening in the ground

A new location, additional depth or different construction method is compared with previous results. A familiar project name does not replace this comparison. Feedback is provided before the affected work so that an outstanding question can be included in the sequence.

Hand over the report and plan together

The technical conclusion remains connected to its location references and appendices. A brief summary helps orientation but does not replace the documented survey scope. This basis is retained even if site management or contractors change.

Understand the results

Use technical statements for the next decision

Distinguish information about an area from an investigation statement

A municipal overview can help locate and assess a property. The ordnance question needs the relevant findings and reports. Read their spatial scope and limitations together with the construction plans. The area information thus remains useful without being used as specialist evidence for an investigation it does not describe.

Understand investigation reports and their limitations

Consider building connections beyond the property boundary

Draw planned trenches and chambers up to their intended transfer points. State depths and necessary works in the road. Specialist services needed are coordinated with traffic management and utility operations. An investigation scope confined to the building footprint does not automatically cover these additional ground interventions, even if they form part of the same construction commission.

Understand the service scope
Design and findings

Documents for the next construction decision

Illustration: aerial photographs and maps on two screens and printed on a desk.

Historical evidence and the current design

Aerial photograph interpretation is related to the actual groundworks. Its purpose and geographical scope remain distinct from a technical investigation of the ground as it is today.

Understand aerial photograph assessment
Illustration: two people review plans and documents at a table beside a construction vehicle.

Specialist reports for site management

The findings, their locations and limitations are handed over together. This makes clear to those carrying out the work which area has been investigated and which task remains outstanding.

Assess investigation reports
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.
Questions from planning

Questions about construction projects in Saarbrücken

Does an entry in the vacant building plot register prove that a site is free of ordnance?

No. The city’s register describes opportunities for development within the built-up area. Whether the planned ground intervention is covered by an ordnance investigation must be checked using the relevant reports and plans. Including an area in the register does not replace this evidence.

Can a report from the neighbouring property be used?

Such a report may provide information for preparation. However, its investigation result initially applies to the area and task described in it. Whether the report is also usable for your own property must be assessed by specialists using its area boundaries, investigation conditions and results.

Do building service connections need to be included in the enquiry?

Yes, if they form part of the planned ground intervention. For new construction within a city in particular, connection trenches and chambers may lie outside the building footprint. Their location and depth should therefore be provided together with the main excavation.

What happens if an area is accessible only after demolition?

The area is marked as not yet available for investigation or unresolved. Designers and the specialist contractor agree what information is available and which next investigation step is required once access is established. Until the necessary investigation, no corresponding result may be assumed for this area.

What should you do if a suspicious object is found?

Stop the affected work. Do not touch, move or relocate the suspicious object, and do not uncover it further. Leave the danger area, keep others away and call the police on 110 from a safe distance. Do not take the object to a police station. Follow the competent authorities' instructions.

Why should the excavation’s working space also be drawn?

Actual works in the ground can extend beyond the future building footprint. Their spatial extent and depth are decisive for the investigation.

Which cost factors matter for excavations, retaining structures and connections?

Usable preliminary work is taken into account. The work required depends on outstanding specialist questions and the volume of ground actually to be investigated. Areas, intervention depths, access before and after demolition, existing structures and interference influence the scope. Necessary historical work, suitable field methods, assessment and documentation are also included. For a quotation, the excavation, retaining structures and connection works are therefore described together with the existing results documentation. This defines a specific scope of services for your project.

What is checked after the building outline changes?

Whether the new ground interventions, with their areas and depths, are covered by the documented investigation result and which additional clarification is necessary.

Project enquiry

Discuss excavation, demolition and connections

Show the complete ground intervention

Draw the excavation, retaining structures, working space and connections.

State working levels and proposed base levels for the excavation, retaining structures and foundations. Exploratory ground investigations, utility trenches and preparatory ground works are also given a location. The investigation can then relate to the volume actually affected rather than only to the future building outline.

State existing conditions and sequence

Send access details, demolition plans and existing results records together.

Identify known obstacles, existing reports and associated appendices. For areas accessible after demolition, the next planned investigation step is agreed. An open execution option remains distinguishable from the settled plans. Assign further project locations using the Saarland overview.

GPR on a construction site
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.