paintwork is found sound, over coating can be done with similar paint but may
be painted with a dissimilar paint ensuring that the previous one is not affected.
Surface Preparation & Painting:
Steel & iron Works: If signs of pitting blistering or flaking is found, it states that
the underbody has started corroding. Over coating will not give any fruitful result.
In this case the paintwork should be completely removed from the surface and
work to bright metal by both mechanical & chemical means. Soon after
completion of surface preparation, a quick application with a suitable primer is
essential. If the paintwork is sound, make the surface free from dusts, oily
matters etc, and rub gently with fine-emery paper. Dust off & overcoat with
suitable topcoat finish paint.
Plaster and Cement renderings:
Check the soundness of paint. If there is flaking or raptures then the whole
paintwork should be taken off. It should then be rubbed down to a smooth
surface. Apply a coat of Plastron Sealer followed by 2 coats of topcoat finish
If the paintwork is affected by efflorescence or growth of fungi or algae this
has to be dealt neatly as described earlier. Ensure that the substrate is dry
before painting. On weak surface a suitable primer is essential.
If the previous paintwork is sound it can be painted with similar type of paint.
Otherwise it should be ensured that the previous one is unaffected by the
dissimilar paint before the total paintwork is carried out.
Paints should be selected depending on the substrate and the condition
If general primers do bot have weather resistance as such should be over
coated with a finishing paint within a month. Undue delay will destroy efficacy of
the primer. In that case it should be rubbed down and then prime again. Primed
material of all building units arriving at a site should be inspected for damage
and if found defective in any way should receive proper remedial attention.
Typical defects are bruised wood, unprimed end grain, rust blisters on primed
steelworks and mould infected joinery units.
All defective priming coats should be removed and the surface exposed should
be fully prepared by appropriate method.
Painting: Primed surface should be over coated with specified finish coats
without undue delay in exposed situations.