Painting and Decorative Coatings

EN 13300 and EN 1062-1 require substrates to be clean, dry, stable, and free from defects before painting. Plaster substrates must be fully cured (minimum 4 weeks for gypsum plaster, 28 days for cement render). CTE DB-HS1 requires that any moisture-related defects be resolved before applying coatings. Surface alkalinity must be tested on cementitious substrates — pH above 10 requires an alkali-resistant primer.

1. Verify substrate moisture content is within acceptable limits using a moisture meter — maximum 5% for plaster, 4% for cement render per coating manufacturer requirements

2. Check substrate for cracks, loose material, efflorescence, and biological growth — all must be treated before painting

3. Confirm surfaces are sanded smooth and free from dust, grease, and contaminants

4. Verify appropriate primer is applied — alkali-resistant primer on new cementitious substrates, stain-blocking primer on water-stained areas

5. Check that fillers and repair materials are fully cured, sanded flush, and compatible with the coating system

- Painting over damp or uncured plaster causing blistering and peeling

- Efflorescence on masonry substrates not treated before painting

- Inadequate surface preparation leading to poor adhesion

- Missing primer coat on new plasterboard or bare substrates

UNE-EN 13300 classifies interior water-borne coatings by wet scrub resistance (Class 1 to Class 5), contrast ratio (opacity classes), and gloss level. UNE 48243 further classifies interior plastic paints used in Spain. Minimum two coats are required over primer for full opacity. Wet scrub resistance Class 2 or better is recommended for high-traffic areas, kitchens, and bathrooms.

1. Verify paint product matches specification — check classification per UNE-EN 13300 for wet scrub resistance class, opacity class, and gloss level

2. Confirm correct number of coats applied — minimum one primer plus two finish coats for new substrates

3. Measure dry film thickness using a non-destructive gauge to verify adequate build per manufacturer requirements

4. Check for uniform colour, consistent sheen, and absence of roller marks, brush marks, or lap lines under raking light

5. Verify that wet areas (bathrooms, kitchens) have coatings with wet scrub resistance Class 1 or Class 2 per UNE-EN 13300

- Insufficient number of coats causing poor opacity and visible substrate

- Low wet scrub resistance paint used in bathrooms and kitchens

- Visible roller marks and lap lines from poor application technique

- Colour variation between walls from different paint batches

UNE-EN 1062-1 classifies exterior masonry coatings by water permeability (W1-W3), water vapour transmission (V1-V3), and crack-bridging ability (A0-A5). CTE DB-HS1 requires external walls to resist rain penetration based on the exposure zone. UNE 48260 specifies requirements for exterior facade paints in Spain. Coatings must allow vapour transmission while preventing liquid water ingress.

1. Verify exterior coating classification per UNE-EN 1062-1 — water permeability class W3 (low) recommended for exposed facades per CTE DB-HS1

2. Confirm water vapour transmission class allows adequate breathability — V1 (high) for historic masonry, V2 for modern renders

3. Check that crack-bridging class is appropriate where substrate cracking is expected — minimum A2 for facades with hairline cracking

4. Verify correct system build — primer plus minimum two coats of exterior paint at manufacturer-specified spread rate

5. Inspect for uniform coverage, consistent colour, and no runs, sags, or missed areas on all facade surfaces including returns

- Impermeable coating trapping moisture behind the facade causing blistering and spalling

- Exterior paint with insufficient water resistance for the exposure zone per CTE DB-HS1

- Coating applied too thin providing inadequate weather protection

- Film-forming paint applied to damp masonry causing early failure

UNE-EN 927 (parts 1-6) specifies coatings for exterior wood, including classification, performance requirements, and test methods. Exterior wood coatings are classified as stable (opaque), semi-stable (semi-transparent), or non-stable (transparent). CTE DB-SE-M requires timber elements to be protected against decay and insect attack. Interior woodwork coatings must meet EN 13300 or EN 927 depending on the product type.

1. Verify wood coating type is appropriate for the location and exposure — exterior joinery requires coatings classified per UNE-EN 927-1

2. Confirm wood moisture content is within range before coating application — maximum 18% for exterior, 12% for interior per manufacturer requirements

3. Check that all surfaces, edges, and end grain are coated — end grain requires additional saturation coats to prevent moisture uptake

4. Verify correct system application — stain or preservative base coat plus specified number of finish coats

5. Inspect for uniform colour, smooth finish, and no runs, sags, brush marks, or missed areas on all timber surfaces

- End grain left uncoated or insufficiently sealed allowing moisture ingress and decay

- Film-forming coatings applied to wood with excessive moisture content causing blistering

- Exterior wood stain applied too thinly providing inadequate UV and weather protection

- Incompatible preservative treatment and topcoat system causing adhesion failure

EN ISO 2409 specifies the cross-cut adhesion test for coatings. EN ISO 2808 defines methods for determining film thickness. Coatings must be applied within manufacturer-specified temperature and humidity ranges — typically 5-35 degrees C and below 85% relative humidity. Recoat intervals must be observed to ensure inter-coat adhesion. Masking and protection of adjacent surfaces is required for clean paint lines.

1. Perform cross-cut adhesion test per EN ISO 2409 on sample areas — result must be Class 0 or Class 1 for adequate adhesion

2. Measure dry film thickness with a gauge per EN ISO 2808 — verify total system build meets manufacturer specification

3. Inspect all surfaces under raking light at 45 degrees to identify roller marks, brush marks, runs, sags, curtains, and orange peel

4. Check cut-in lines at junctions between walls, ceilings, door frames, and windows for straightness and cleanliness

5. Verify that adjacent surfaces (glass, hardware, floor finishes) are free from paint splashes and overspray

- Poor adhesion from painting outside manufacturer temperature and humidity limits

- Insufficient dry film thickness from over-thinning or excessive spread rates

- Visible brush and roller marks from poor application technique or incorrect roller sleeve

- Paint splashes on glass, hardware, and floor finishes from inadequate masking

RD 117/2003 (transposing EU Directive 2004/42/CE, the Decopaint Directive) limits volatile organic compound (VOC) content in decorative paints and varnishes sold in Spain. Interior matt wall paints are limited to 30 g/L VOC, interior gloss paints to 100 g/L, and exterior masonry paints to 40 g/L. Product labelling must declare VOC content and subcategory. Adequate ventilation must be provided during and after application.

1. Verify paint product labels declare VOC content in g/L and confirm values are within limits per RD 117/2003 and EU Directive 2004/42/CE

2. Check that product subcategory on the label matches the intended use — interior wall, exterior masonry, trim, varnish, etc.

3. Confirm adequate ventilation is provided during application and drying — natural or mechanical ventilation per RITE requirements

4. Verify that low-VOC or zero-VOC products are used where specified, particularly in schools, hospitals, and occupied buildings

5. Check that paint waste, containers, and solvents are disposed of according to waste management regulations

- Products exceeding VOC limits used without verification of label compliance

- Inadequate ventilation during interior painting causing occupant discomfort and health risks

- Solvent-based products used where water-based alternatives are specified or required

- Paint waste and solvent-contaminated materials disposed of improperly