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QUESTION: What is Steelseal?

ANSWER: Steelseal is a high performance paint system specifically formulated for the overcoating and maintenance of various types of 'coil coated cladding'

QUESTION: Are coatings like Steelseal suitable for all types of pre-coated cladding materials?

ANSWER: Steelseal utilises a range of specialist primers according to the substrate to be overpainted eg: PVC plastisol, PVF2, Polyester/Silicone polyester, Powder Coated Cladding, Steel, Galvanise aluminum.

QUESTION: How can I identify what type of finish I have got on my cladded building?

ANSWER: The most common finishes are Plastisol, PVF2 and Polyester coil coatings. The Plastisol can be readily identified by its inherent 'leather grain' surface texture and more recently the Scintilla emboss. Plastisols are typically high build i.e. over 100 micron and the standard finish is a 200 micron dry film thickness. The PVF2 and Polyester finishes by comparison are a smooth finish and thin film typically 25-30 micron. (Further information can be found within the ‘Choosing the correct specification’ area of this website)

QUESTION: If we are planning to overpaint our buildings as part of an overall maintenance programme how do we know when treatment is needed and if it is suitable for repainting ?

ANSWER: Visual inspection of the cladding will determine whether the surface has begun to break down, and if so which stage of deterioration has been reached. The main stages can be summarised as:

Chalking - white chalk-like powder appears on the surface. There may be colour change or loss of gloss. The original coating is still intact with good adhesion. Planned maintenance repainting at this stage will restore buildings to their original appearance.

Coating breakdown - evidence of microchecking (fine crazing of surface coating through to bare metal). If the adhesion of the coating is satisfactory repainting can still be used to remedy the condition.

Failure of coating and corrosion of metal coating below - total neglect of the original coating resulting in unsightly corrosion of galvanised steel substrate. It is still possible to restore the cladding to an acceptable aesthetic appearance if caught before perforation or general thinning of the metal. If this happens replacement of the cladding will be necessary.
(Further Information can be found within the ‘Maintenance of Architectural Cladding’ section of this Website)

QUESTION: How often should cladding normally need repainting ?

ANSWER: Depending upon the external environment and the particular cladding type, average life to first major maintenance can vary between 7 and 20 years. Regular visual inspection is recommended in order to identify the onset of the initial chalking phase at which time overpainting is the ideal treatment.

QUESTION: What level of preparation is required prior to treatment?

ANSWER: This will greatly depend on the type and surface condition of the finish. However we can provide standard specification sheets on request, which assume certain typical site conditions. If caught at the right time the minimum requirement includes water pressure-jetting clean down. Plastisol deteriorates in a different manner to PVF2 etc; quite often the preparation is obvious in that the Plastisol is peeling, flaking or micro-checking and will therefore require removal.
To ensure maximum system longevity it is not enough to rely on visual assessment alone, and adhesion checks should be carried out.

QUESTION: What types of adhesion checks?

ANSWER: A St Andrews Cross Cut test is recommended. This is two lines cut through the coating (with a sharp decorators knife i.e. 'Stanley' type of similar) to the substrate beneath, at the 'V' intersection of the lines the knife should test the adhesion by inserting the point of the knife at the 'V' intersection and firmly dragging or flicking the knife upwards or forwards. This is a practical on site adhesion check that will give an indication of the factory coating adhesion, and whether it will support a redecoration. The coating shall be deemed sound to overpaint if no or very little of the coating is removed by the above test. If the coating can be quite readily chased up the surface with the knife, it shall be deemed unsound, and removal of the coating is required prior to treatment. (Further Information can be found within the ‘Condition of Existing Cladding’ section of this Website)

QUESTION: How many coats do I have to apply?

ANSWER: The Steelseal system is designed for one primer coat followed by one application of topcoat. In some rare situations two coats of topcoat should be applied.

QUESTION: Do I need to prime the cladding?

ANSWER: Yes, in all instances. Failure to prime will affect the coatings adhesion and its performance.

QUESTION: What primer do I need for my cladding?

ANSWER: Two specialist primers are available, one for Plastisol and another for PVF2, Silicone Polyester, Architectural Polyester and Galbestos etc. these are as follows:

PC4VC – Steelseal primer for steel, galvanised and plastisol for application by brush or airless spray.

PVF2, Silicone Polyester, Architectural Polyester, Powder Coated Cladding, Alkyd and Epoxy Coil coated cladding; Steelseal cladding repaint P.U Primer PC4WO Series, this is a dual purpose grade it can be brushed or airless sprayed.

QUESTION: Can I apply Steelseal by Roller application?

ANSWER: Yes, However it must be strictly monitored, as there is a tendency to spread the paint out too much, this leads to the paint being under specification. Therefore any roller application must be monitored and 'laid off' with a brush.

QUESTION: My cladding has been overcoated / repainted in the past, does it still need a primer?

ANSWER: Assuming the current coating has good adhesion and passes the St Andrews Cross Cut Test, then we can provide a compatible undercoat ie Urethane Alkyd Undercoat 5AS Series. This will promote adhesion to the existing coating and provide a suitable base for the Steelseal topcoat. Standard Steelseal Primers should not be used on previously repainted cladding.

QUESTION: What finish coat do I use?

ANSWER: Steelseal Topcoat ref PC5VF Series, this is applied over any of the Steelseal primers (and 5AS series undercoat if required) in one or two applications.

QUESTION: What topcoat colours are available?

ANSWER: The Steelseal Topcoat is available in an almost unlimited colour choice including British Standard, RAL and NCS colour palettes.

This enables an organisation's corporate house colours to be faithfully reproduced, maintaining a consistent image and presentation of the business through its premises.

QUESTION: How long will it last?

ANSWER: When applied in accordance with the product data sheets and specification requirement a 10-year life expectancy is achieved.

QUESTION: Are standard decorative paints OK for overpainting cladding ?

ANSWER: Absolutely not - conventional decorative paints such as gloss or eggshell simply aren't up to the job. That is not to say that some building owners and contractors don't apply them in an attempt to reduce costs.
However this is certainly false economy and will be paid dearly for in the longer term.
Specially formulated high performance coating system such as STEELSEAL from Akzo Nobel provide a tailor made solution, whatever the reasons for redecoration. Steelseal was originally developed as a maintenance and repair treatment for the market leading Colorcoat cladding products from Corus (formerly British Steel), and is still their only recommended overpainting system.

QUESTION: Can overpainting be carried out by most local decorating contractors ?

ANSWER: In general terms Yes, depending upon the scale of works each contractor has experience of and the equipment to handle. Steelseal application is straight forward by either airless spray or brush, and should be well within the capabilities of most experienced industrial painting firms, however we would recommend that a specialist contractor is used.
For larger scale applications it is wise to appoint a specialist applicator who has specific experience in cladding maintenance and redecoration.
Correct surface preparation, and identification of the substrate is crucial, and in some cases mastic systems need to be applied to seal overlap joints and for the repair of damaged coating on roof sheets. These procedures are best entrusted to experienced operatives. There are a number of contractors specialising in the treatment and protection of metal cladding, who work on a national or regional basis. Please feel free to contact us for contractor recommendations.