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Gaps and cracks should be filled with a suitable filler and sanded lightly to an even finish.

DIY Exteriors

Step 3: Surface Preparation

Proper surface preparation is just as critical as proper painting practices. If the surface is not prepared correctly, various problems can occur.

It is estimated that over 95% of all paint failures are attributed to inadequate surface preparation.

Painting Surface Preparation 1

1. It is essential that the surface to be painted is thoroughly clean and dry.

Ensure surface is clean & dry, and free from chalking, loose friable material, dust, dirt & grease. If mould is present, clean surface with household bleach then rinse well with clean water. Wear eye protection when using bleach.

Painting Surface Preparation 2

All loose, peeling or flaking material must be removed. Uneven surfaces should be sanded smooth with fine abrasive paper and all dust removed.

Glossy Enamel surfaces: Dull glossy surfaces by sanding to promote proper adhesion.

2. Be sure to repair and correct any underlying surface issues.

Painting Surface Preparation 3

Repair or replace damaged or rotten wood as needed.

Test soundness of previously painted surfaces by cutting a small X in the paint with a sharp blade. Stick a piece of tape firmly over the X and pull off. If the paint pulls away, the surface is unsound. Repeat at random in a number of areas. Unsound surfaces should be stripped for best results.

Painting Surface Preparation 4

Peeling paint is a result of poor adhesion, usually caused by moisture, poor surface preparation or inferior paint quality. Be sure to identify and eliminate the cause of moisture, then scrape off any loose or peeling paint. Test soundness of remaining paint (see above). Sand the edges and remove the dust.

Painting Surface Preparation 5

Chalking is the formation of a powder film on the surface to be painted and is usually the result of the existing paint film wearing away. Clean the surface with a pressure washer or a stiff brush to remove all residue. Rinse with a garden hose. When dry, ensure chalking has been removed.

Painting Surface Preparation 6

Bubbles or blistering can occur from painting in warm direct sunlight, or moisture trapped behind the paint film. The first step is to remove the source of the moisture. Then, remove the blisters by scraping or sanding.

Where multiple or substantial areas have blistered or peeled, it is recommended to strip the entire surface to prevent the old paint blistering or peeling when repainted.

Gaps and cracks should be filled with a suitable filler and sanded lightly to an even finish.

Keep reading...

Step 1: How much paint do I need?

Step 2: Which sheen should I use?

Step 3: Prepare the surface

Step 4: Let's paint

Step 5: Which tools do I need?

Step 6: Clean-up, storage & disposal

Guide Download

Download a PDF of our DIY Exterior Painting Guide

See also