Painting & Coatings Inspection

Per EN 13300, substrates for interior painting must be clean, dry, sound, and free of contaminants. EN ISO 8501 defines preparation grades for steel substrates (Sa 2.5 for blast cleaning, St 2/St 3 for hand/power tool cleaning). Concrete and plaster substrates must have moisture content below 5% (measured by CM method) before paint application. Plasterboard must be finished to the required quality level (Q2-Q4) per EN 13914-1 before painting.

1. Verify substrate is dry — measure moisture content with a calibrated meter (below 5% CM for masonry/plaster)

2. Check plasterboard finish quality matches the specified Q level for the planned coating type

3. Confirm steel surfaces are prepared to the specified grade per EN ISO 8501 (e.g., Sa 2.5)

4. Verify all surfaces are free of dust, grease, efflorescence, and loose material

5. Check that cracks and holes are filled, sanded smooth, and primed before top coat application

- Substrate too wet, causing blistering or peeling of paint film

- Plasterboard joints not finished to adequate quality level, showing through paint

- Steel not prepared to specified grade, causing premature coating failure

- Dust or contaminants on the surface reducing paint adhesion

Per EN 13300, interior water-borne paints are classified by wet scrub resistance (Class 1 to Class 5, with Class 1 being the most durable), covering power (hiding power classes at specified spread rates), and gloss level. VOC content must comply with EU Directive 2004/42/EC maximum limits for the relevant product subcategory. Paint must be applied in the number of coats and at the spread rate specified by the manufacturer to achieve the declared performance.

1. Verify paint product matches the specification and is classified per EN 13300 — check product data sheet

2. Confirm wet scrub resistance class is appropriate — Class 1 or 2 for kitchens, bathrooms, and high-traffic areas

3. Check that primer/undercoat has been applied where specified, especially on new plaster or plasterboard

4. Verify number of top coats applied — minimum two coats for full coverage and performance

5. Measure wet film thickness during application using a wet film gauge per EN ISO 2808

6. Confirm VOC content is within EU Directive 2004/42/EC limits as stated on the product label

- Wrong scrub resistance class for the application (e.g., Class 5 in a kitchen)

- Primer omitted on absorbent substrates, causing uneven finish and poor adhesion

- Insufficient coats applied, giving inadequate coverage and durability

- VOC limits exceeded, particularly with solvent-borne products

Per EN 1062-1, exterior coating systems for masonry and concrete are classified by water permeability (W1 low, W2 medium, W3 high), CO2 permeability, crack bridging ability (A1-A5), and film thickness (E1-E5). The coating system must be selected to suit the substrate type, exposure conditions, and required maintenance interval. Application must achieve the specified dry film thickness to deliver the declared performance characteristics.

1. Verify coating system is classified per EN 1062-1 and matches the specification for exposure conditions

2. Confirm water permeability class is appropriate — W3 (breathable) for historic masonry, W1 for exposed locations

3. Check crack bridging class if specified — A2 minimum for substrates with existing fine cracks

4. Measure dry film thickness per EN ISO 2808 — confirm it meets the minimum for the declared E class

5. Verify primer and intermediate coats have been applied as specified in the coating system

- Coating system not suited to the substrate or exposure, leading to premature failure

- Wrong water permeability class trapping moisture in the substrate

- Insufficient film thickness reducing weather resistance and durability

- Application in unsuitable weather conditions (rain, frost, high temperatures)

- No primer on porous substrates, causing variable absorption and patchy finish

Per EN 927-1 to EN 927-6, coating systems for exterior wood are classified and tested for performance including resistance to weathering, water permeability, and fungal growth. Wood substrates must be classified for natural durability per EN 350, and the coating system must be compatible with the timber species and preservative treatment. Moisture content of timber at the time of coating must be between 12% and 18% for exterior joinery.

1. Verify coating product is tested per EN 927 series and is compatible with the timber species

2. Measure timber moisture content — must be 12–18% for exterior joinery at time of coating

3. Check that all end grain is sealed with appropriate primer or end grain sealer

4. Confirm specified number of coats applied — typically primer plus two top coats for exterior wood

5. Verify back and hidden faces are coated to prevent moisture uptake from uncoated surfaces

6. Check timber durability class per EN 350 is appropriate for the use class per EN 335

- Timber too wet at time of coating, causing blistering and peeling

- End grain not sealed, allowing rapid moisture uptake and coating failure

- Back faces uncoated, causing differential moisture movement and warping

- Coating system incompatible with timber preservative treatment

Per EN ISO 2808, film thickness of applied coatings must be measured using appropriate methods — wet film gauges during application and dry film thickness (DFT) gauges after curing. Coverage rates must match the manufacturer's stated spreading rate to achieve the declared film build. The finished coating must be free of visible defects including runs, sags, misses, brush marks (where spray finish is specified), and colour variation.

1. Measure wet film thickness during application with a wet film comb per EN ISO 2808

2. Measure dry film thickness after curing using magnetic or eddy current gauge per EN ISO 2808

3. Visually inspect for runs, sags, curtains, and brush marks under appropriate lighting

4. Check colour consistency across the installation — verify batch numbers are consistent

5. Perform adhesion test per EN ISO 2409 (cross-cut test) on a sample area — minimum Class 1 result

- Film thickness below specification due to over-spreading or excessive thinning

- Runs and sags from over-application or incorrect viscosity

- Colour variation between areas due to different paint batches

- Poor adhesion due to contaminated substrate or incompatible primer

Per EU Directive 2004/42/EC (the Paints Directive), decorative paints and varnishes and vehicle refinishing products must comply with maximum VOC content limits expressed in grams per litre. EN 16516 provides the method for testing emissions from construction products, including paints, into indoor air. Products must display the VOC content and applicable subcategory limit on the label. National regulations may impose additional requirements for indoor air quality.

1. Verify VOC content on the product label does not exceed the EU Directive 2004/42/EC limit for the subcategory

2. Confirm the product subcategory is correctly identified (e.g., interior matt walls and ceilings: max 30 g/L)

3. Check that products used in sensitive environments (schools, hospitals) meet any additional national low-emission requirements

4. Verify adequate ventilation is provided during and after application per manufacturer's recommendations

5. Review product emissions testing certificates per EN 16516 where indoor air quality certification is required

- Product VOC content exceeds the applicable limit for the declared subcategory

- Product subcategory incorrectly identified, applying the wrong VOC limit

- Inadequate ventilation during application, creating health risks for workers

- No emissions test certificates available for products used in buildings requiring indoor air quality compliance

- Solvent-based products used where water-borne alternatives are required by regulation