No Con Drop – Roofing sheets

Are used for profile sheets on roofs which can be subject to condensation on the underside and prevents dripping in such cases

Typical buildings that use No Con Drop:

  • Uninsulated Warehouses

  • House extensions

  • Garages - Car ports

  • Parapet roofs

  • Agricultural Building

  • Open Shelters


No-Con-Drop is a precoated steel sheet with moisture absorbing fibre fabric on the underside. The fabric is applied to any of our profiles in an online process.

The moisture absorbing function

Condensation on the underside of the profile sheets occurs when the temperature of the sheet is equal to or lower than the dew point of the air under the sheet. The fibre fabric has the capability to absorb at least 200 grams of water per square meter which is considered to be more than sufficient for most applications. Between the condensation periods the fibre fabric dries out. For this reason the building must be ventilated.

Properties for the fibre fabric

Polyester fabric with an admixture of cellulose fibres and acrylic binder.

Surface weight:
80 g/m2

Tolerance, absent width:
+7/-0 mm

415 um

Moisture absorption:
Adapted to normal requirements.(measured by condensation tests and found to be at least 200 g/m2).


Detail Design of Roofs

Profiled sheets with NoConDrop are installed in the same way as sheets without fibre fabric with some exceptions.Due to the capilliary action properties of the fibre the following precautions MUST be made to prevent that water is drawn back under the sheet at lower sheet tails and at endlaps.

– Lower sheet tails and the topsheet at endlaps should be painted with a transparent impregnating liquid or alkyd lacquer. See fig. 2


No Con Drop should not be installed directly on water absorbing materials, for instance timber purlins. In such cases the timber should be covered with a strip of asphalt felt or similar material.

At roofpitches lower than six degrees we advise that the bottom of the profile is bent down to form dripspouts. See fig. 3

See that the interior of the building or the space under the roof is well ventilated, in order to insure that the absorbed moisture will in due course evaporate from the fibre fabric coating.


At installation be careful not to damage the fibre when transporting the sheets over purlins. It is natural that the porous surface of the fibre can be easily soiled. Use therefore clean working gloves when handling the sheets.

DO NOT walk on the fibre before installation !


Both topcoating and the fibre fabric have class I fire-resistant surface as per BS 476 Part 7. The fibre fabric is frost resistant and resistant to mould growth.

Limitations of the product

The use of polyester coating in a distinctly marine location i.e. within 300 meters of open coast, will mean that inspection of the polyester topcoat needs to take place at more regular intervals. i.e. every two years.

Repainting will also be necessary earlier and will depend upon the inspection results. Use of NoConDrop for animal housing will lead to ammonia on the underside of the sheet which will restrict the total sheet life.

Repair of top coating and fibre fabric

Any damages to the coating during handing should be repaired. Major damage on the fibre fabric can be remedied by bonding a new fibre fabric to the underside. A water resistant adhesive can be used.

For re-laminating, Cladco can supply small quantities of fibre fabric.

Technical service and information

Further information can be obtained from Cladco


Care should be taken to avoid damage to the coating during profiling and installation. Storage of the material outdoors should be avoided. However, if this is unavoidable, the material should be satisfactorily covered and should be stored in a manner that will ensure good air circulation, in order to avoid accumulation of moisture.

For particulars of tolerances and characteristics in general, please refer to the relevant European and ECCA (European Coil Coaters Association) standards