Concrete — cover to reinforcement
Minimum and nominal concrete cover to reinforcing steel to EN 1992-1-1 including the Czech National Annex, for exposure classes X0, XC, XD and XS.
Exposure and concrete
Informative example (Table 4.1): concrete inside buildings with low air humidity; concrete permanently submerged in water.
Not used when the structural class is entered manually.
Not used when the structural class is entered manually.
Reinforcement
A bundle of bars of the same diameter. The cover is measured from the actual outside contour of the bundle (clause 8.9.1(3)).
Enter the reinforcement for which you are determining the cover. For a member with several layers or different bar diameters, more than one case may need checking.
Further parameters
Show advanced settings
Not used when the structural class is entered manually.
Not used when the structural class is entered manually.
The calculator does not verify these conditions. Their fulfilment is your input assumption.
For concrete cast against an uneven surface the nominal cover should be at least 40 mm or 75 mm (clause 4.4.1.3(4), NA.2.26).
For XS1–XS3 the structural class is entered manually under Exposure and concrete.
Choose the structural class deliberately; the calculator fills in no default class.
Δcdur,γ = Δcdur,st = Δcdur,add = 0 mm (NA.2.20 to NA.2.22). Read only.
| Criterion | X0 | XC1 | XC2 | XC3 | XC4 | XD1 | XD2 | XD3 |
|---|---|---|---|---|---|---|---|---|
| Design working life of 80 years | +1 | +1 | +1 | +1 | +1 | +1 | +1 | +1 |
| Design working life of 100 years | +2 | +2 | +2 | +2 | +2 | +2 | +2 | +2 |
| Concrete strength class at least (−1) | C20/25 | C25/30 | C30/37 | C35/45 | C40/50 | C40/50 | C40/50 | C45/55 |
| Member with slab geometry | −1 | −1 | −1 | −1 | −1 | −1 | −1 | −1 |
| Special quality control of the concrete production ensured | −1 | −1 | −1 | −1 | −1 | −1 | −1 | −1 |
The default class is S4 (50 years), the lowest S1. Table 4.3CZ has no columns for XS1–XS3.
| Class | X0 | XC1 | XC2/XC3 | XC4 | XD1/XS1 | XD2/XS2 | XD3/XS3 |
|---|---|---|---|---|---|---|---|
| S1 | 10 | 10 | 10 | 15 | 20 | 25 | 30 |
| S2 | 10 | 10 | 15 | 20 | 25 | 30 | 35 |
| S3 | 10 | 10 | 20 | 25 | 30 | 35 | 40 |
| S4 | 10 | 15 | 25 | 30 | 35 | 40 | 45 |
| S5 | 15 | 20 | 30 | 35 | 40 | 45 | 50 |
| S6 | 20 | 25 | 35 | 40 | 45 | 50 | 55 |
Read only. The structural class in use and the column of the exposure class are highlighted.
The result does not include fire resistance (EN 1992-1-2), additions for abrasion (XM), construction joints, uneven surfaces to clause 4.4.1.2(11) or prestressing steel. Nothing is added for exposure classes XF and XA, per clause 4.4.1.2(12).
- The calculator determines the minimum and nominal cover to reinforcing steel to clause 4.4.1 of EN 1992-1-1 and the Czech National Annex. Prestressing steel is not covered.
- For exposure classes X0, XC1–XC4 and XD1–XD3 the structural class is derived from Table 4.3CZ of the Czech National Annex; the individual modifications are added together. For XS1–XS3 Table 4.3CZ gives no rules, so the structural class is entered manually.
- An allowance for deviation below 10 mm depends on quality-control and cover-measurement conditions to NA.2.24 or clause 4.4.1.3(3). The calculator does not verify them.
- The calculation covers one selected reinforcement. For a member with several layers or different bar diameters, more than one case may need checking.
- The result does not include fire-resistance requirements (EN 1992-1-2), abrasion (XM), construction joints or additions for uneven or profiled surfaces to clause 4.4.1.2(11).
- This is not a substitute for a complete structural design.