Which trade does the monitoring line item belong to?

Two variants are common: as a position within the screed trade (the screed layer places the sensors during installation) or as a separate position for site management/the client. Placement during screed installation is the most economical because no separate appointment is needed.

Does the monitoring position replace the CM test in the specification?

No. The CM test remains its own position — it is the recognised proof of covering readiness. Monitoring reduces the number of CM appointments needed because it delivers the right timing.

What must the line item contain at minimum?

Scope (number of sensors per area, room climate sensor, gateway), placement (before/after screed installation), data provision (access for site management and planners, report format), operating period (until covering readiness or project end) and the separation from the CM test.

How many sensors per area are sensible?

As a guide value, one material sensor per room or per [PLACEHOLDER: m² guide value from pilot practice] m² started has proven itself, plus one room climate sensor per storey or construction stage. Floor plan, screed type and layer thicknesses are decisive.

Specifying moisture monitoring in the bill of quantities

Specifying screed moisture monitoring: line item wording, CM-test separation, payment models. Templates for CAF, CT and existing concrete.

Moisture monitoring only works if it is anchored in the project from the start — and that means: in the bill of quantities. Retrofitting it on site loses the early data from the critical initial phase and forces renegotiation of responsibilities. This article shows what a clean specification line item for screed moisture monitoring looks like and what planners should consider regarding payment and separation of duties.

Why put it in the specification?

Three reasons favour a dedicated line item:

Clear responsibility. The position defines who places the sensors (usually the screed layer during installation), who is responsible for operation and who gets access to the data. Without it, the typical grey areas appear: who pays? Whose data is it? Who reacts to alerts?
Economical placement. During screed installation, positioning an embedded sensor takes minutes. Retrofitting means a separate appointment with a drill hole at the measuring point.
Comparable bids. A precisely worded position makes bids comparable — instead of every bidder meaning something different by “monitoring”.

Structure of a clean monitoring position

A complete line item covers five building blocks:

1. Scope. Number and type of sensors (material sensor in the screed, room climate sensor), gateway for data transfer, access to the evaluation platform. Guide value: one material sensor per room or area grid, one room climate sensor per storey.

2. Placement. Timing (during screed installation or retrofitted at the measuring point), positioning (representative location, deepest zone of the layer, distance to edge joints and heating circuits) and documentation of sensor positions in the installation plan.

3. Measured values and data provision. Moisture and temperature curve in the material, displayed comparably to the CM reference in g/m³; room climate (temperature, relative humidity). Access for site management, specialist planners and executing trades; alerts at defined thresholds; final report as part of the project documentation.

4. Operating period. From installation until proven covering readiness, optionally until project handover (e.g. to monitor the heating and covering phase). Since the sensor remains fully embedded, the service ends with data access, not with removal.

5. Separation from the CM test. This sentence belongs in every position: Monitoring does not replace the CM test. The CM test remains the recognised proof of covering readiness (DIN 18560 / SIA context); monitoring serves continuous progress control and the scheduling of the CM test.

Payment: three common models

Lump sum per sensor/area: simplest billing, easy for bidders to calculate.
Lump sum per construction stage incl. operation: bundles hardware, placement and data access.
Provided by the client: the client procures the system; the specification only governs placement by the screed layer (minutes per sensor).

Which variant fits depends on project size. For public tenders, product-neutral wording with functional requirements is recommended (embedded sensors, radio transmission through the material, continuous data provision, g/m³ display).

Ready-made templates

So the wording doesn’t start from zero, we provide reviewed specification templates for download:

Line item, flowing screed (CAF) — moisture monitoring, screed drying
Line item, semi-dry cement screed (CT) — moisture monitoring, screed drying
Line item, existing concrete — moisture monitoring before refurbishment/covering

All templates are in the downloads section (PDF and DOCX to paste into your own specification). Background on moisture measurement in existing concrete: measuring moisture in existing concrete.

From specification to running project

After award, the process is lean: define sensor positions in the installation plan, place them during screed installation, connect the gateway — data flows from then on. Site management and planners see the same drying curve, alerts flag stagnation or moisture events, and the CM test is scheduled when the curve justifies it.

To get to know the model before the first tender, test it in a pilot project on a real area.

Frequently asked questions

Which trade does the monitoring line item belong to?: Two variants are common: as a position within the screed trade (the screed layer places the sensors during installation) or as a separate position for site management/the client. Placement during screed installation is the most economical because no separate appointment is needed.
Does the monitoring position replace the CM test in the specification?: No. The CM test remains its own position — it is the recognised proof of covering readiness. Monitoring reduces the number of CM appointments needed because it delivers the right timing.
What must the line item contain at minimum?: Scope (number of sensors per area, room climate sensor, gateway), placement (before/after screed installation), data provision (access for site management and planners, report format), operating period (until covering readiness or project end) and the separation from the CM test.
How many sensors per area are sensible?: As a guide value, one material sensor per room or per [PLACEHOLDER: m² guide value from pilot practice] m² started has proven itself, plus one room climate sensor per storey or construction stage. Floor plan, screed type and layer thicknesses are decisive.