Floor coatings, failure to prepare is preparing to fail

Ben Mottershead of leading coatings manufacturer, Bradite, examines what is involved when undertaking the painting of industrial flooring.

Whether you’re painting flooring in a warehouse, workshop, school or hospital kitchen, an underground car park, or even something more challenging like an aircraft hangar, site preparation and product selection are the keys to success.

It is important to remember that not all floor paints are the same. Generic products include alkyds, polyeurethanes, epoxies, single-pack, twin-pack, water-based, solvent-free, moisture cure, chlorinated rubber and more. They may be described as domestic, industrial, garage, hard-wearing, tough and flexible. Ben provides his advice for selecting the correct product for the job:

For a light industrial situation, the coating should be hard-wearing, grease-resistant and able to cope with light to medium traffic. A water-based cross-linking product such as Bradite Floor-It will work well.

For heavier traffic areas, such as a workshop floor where oil and grease are present, Bradite’s heavy duty HD Floor + Wall system is ideal. To achieve quick drying and recoat times, try a water-based, cross linking product such as Floor-It.

In a working environment, such as an area for food preparation, you should use an odour and solvent-free product. Consider water-based cross linking or twin pack water-based epoxies – both Floor-It and HD Floor + Wall are suitable here.

There are certain circumstances where the coating must resist specific chemicals. In these cases, identify the chemicals and check the coating suitability directly with the product manufacturer.

Substrates

Whether it’s concrete, steel, timber, or something else, the substrate upon which the coating is to be applied is critical. When choosing a coating, consider whether the substrate is new or aged, inside or outside, or previously covered with a different coating.

New concrete should be left for a minimum of 30 days before painting to allow time for it to completely dry out. This can be checked by laying a rubber mat on the floor and leaving it overnight. When removed, if the floor is discoloured or condensation is still visible, then moisture is still present, and the floor should be left until fully cured.

New concrete should also be checked for laitance, a milky deposit on the surface usually caused by excess water in the mix. If painted, it could act as a crust and detach from the base causing premature failure of any coating. This can be removed by blasting or acid etching.

Power floated, shiny or unpainted nonporous concrete flooring should be thoroughly blast cleaned, ground and acid etched. The correct application of screeds is important, so check with the manufacturer to ensure the screed is suitable for overcoating.

The correct preparation of steel substrate depends on whether it is ferrous or non-ferrous. Remove corrosion to brighten the steel, treating any stubborn spots or marks with Bradite Rust Converter before applying a primer, such as Bradite One Can – available in either Matt or Eggshell. If previously painted, all coatings must be well adhered.

Turning to timber, softwood knots should be wiped and sealed using knotting compound or aluminium primer. Resinous hardwoods should be wiped with methylated spirits prior to priming with aluminium wood primer. The moisture content of the timber should be below 15%. Damp wood should never be painted as this will give rise to blistering, flaking and cracking. Damaged, rotten and darkened timber should be repaired prior to product application.

When covering previous and existing coatings, if possible, identify the existing product and check its compatibility with any new coatings. Existing coatings should be well adhered to. Any flaking, damaged or loose material should be removed back to a firm edge. Substrates should be clean, free of oil, grease and dust and completely dry before application of any product.

Preparation

Clean with high pressure wash and sweep to remove all loose debris. Degrease using Bradite’s TD39 Industrial Degreaser and rinse. Lightly abrade the surface, blast or acid etch, vacuum to remove all dust and ensure the substrate is completely dry prior to application of the new coating. With power floated floors, once the surface is cleaned, they can be prepared by vacuum blast, grinding or diamond grinding, acid etching or the use of adhesion primers.

Application

With product selection and preparation now complete, we can move on to application. The method of application will depend on the product selected and the manufacturer’s instructions. As with any application, it is important to understand the product’s recoat, drying, and curing times. This information may be found on data sheets or provided by the product manufacturer.

Remember, most manufacturers will offer on-site and specification help. The old adage holds good: failure to prepare is preparing to fail!