Painting & Decorative Coatings

According to EN 13300 and EN 1062-1, substrates must be properly prepared before paint application to ensure adhesion and durability. Surfaces must be clean, dry, sound and free from dust, grease, efflorescence and loose material. Cementitious substrates require a minimum 28-day curing period and moisture content below 5% (CM method). Portuguese RGEU requires all surface finishes to be applied to properly prepared substrates. Cracks wider than 0.3 mm must be repaired before painting. Previous coatings must be assessed for adhesion and compatibility with the new paint system.

1. Inspect surfaces for dust, grease, efflorescence, mould, loose plaster or flaking paint — all must be removed before painting

2. Measure substrate moisture content with a moisture meter — must be below 5% for cementitious surfaces and below 18% for timber

3. Check surface flatness and repair cracks wider than 0.3 mm with appropriate filler per manufacturer's recommendations

4. Perform a cross-cut adhesion test (EN ISO 2409) on existing coatings to verify adhesion before overcoating

5. Confirm that appropriate primers or sealers have been applied as specified (e.g. alkali-resistant primer on new plaster)

- Painting over damp or uncured substrates, causing blistering and peeling

- Failure to remove dust, grease or efflorescence, resulting in poor adhesion

- Cracks not repaired before painting, reappearing through the finished coat

- Incompatible primer or no primer applied on new or porous substrates

According to EN 13300, interior paints are classified by wet scrub resistance (Class 1–5), contrast ratio (hiding power, Class 1–4) and gloss level. The specification must define the required class for each area — typically Class 2 wet scrub resistance for corridors, kitchens and high-traffic areas, and Class 3 for bedrooms and living rooms. Portuguese RGEU requires that interior finishes are durable and maintainable. Application must follow the manufacturer's data sheet for number of coats (minimum two finish coats), spreading rate, drying times and environmental conditions (temperature 10–30°C, RH < 80%).

1. Verify paint product matches the specification — check EN 13300 classification, colour reference and manufacturer's technical data sheet

2. Confirm the correct number of coats has been applied (minimum two finish coats over primer) by checking wet film thickness and coverage

3. Inspect finished surfaces for uniformity of colour, sheen and texture — no runs, sags, brush marks, roller stipple or missed areas

4. Check that masking and cutting-in lines are clean and straight at junctions with different surfaces or colours

5. Verify environmental conditions during application — temperature between 10°C and 30°C, relative humidity below 80%

- Insufficient number of coats resulting in poor coverage and visible substrate

- Inconsistent sheen or colour due to variable spreading rates or batch differences

- Runs, sags and drips from excessive application thickness

- Paint applied in unsuitable environmental conditions (too cold, too humid), causing slow drying and defects

According to EN 1062-1, exterior coatings are classified by water vapour permeability (V1–V3), liquid water permeability (W1–W3), crack-bridging capacity (A0–A5) and film thickness (E1–E5). The specification must define the required classification based on exposure and substrate conditions. Portuguese coastal and southern regions require coatings with high UV resistance and water vapour permeability (V1 or V2) to manage moisture in masonry. RGEU requires exterior finishes to be weather-resistant and durable. ETICS (External Thermal Insulation Composite Systems) require specific compatible coatings per ETAG 004/EAD.

1. Verify coating product matches the specification — check EN 1062-1 classification, CE marking and suitability for the exposure conditions

2. Confirm water vapour permeability class (V1 or V2 recommended for Portuguese climates) and liquid water permeability class (W3 minimum)

3. Measure dry film thickness (DFT) with a coating thickness gauge — must match the manufacturer's specification (typically 150–300 µm total)

4. Inspect for uniform coverage, colour consistency and absence of defects (runs, holidays, cracking, chalking)

5. Verify application was done in suitable weather — no rain forecast for 24 hours, temperature 8–35°C, substrate temperature above dew point

- Coating with low vapour permeability trapping moisture in masonry, causing blistering

- Insufficient dry film thickness reducing weather protection and durability

- Application during rain or high humidity, causing whitening, blistering or poor adhesion

- Incompatible coating applied over ETICS, causing cracking and delamination

- UV degradation and chalking from using interior-grade products externally

According to EN 927 (parts 1–6), exterior wood coatings must be tested for weather resistance, adhesion and moisture behaviour. Wood moisture content must be between 12% and 18% before coating application. Preservative treatment must comply with EN 351 (durability classes) and be completed before decorative coating. Portuguese climate demands coatings with high UV resistance and fungicidal properties, particularly in humid Atlantic coastal areas. Interior wood finishes (doors, skirting, joinery) must comply with EN 13300 for the relevant performance class. All timber in contact with masonry must receive appropriate protective treatment per RGEU requirements.

1. Measure timber moisture content with a pin-type moisture meter — must be between 12% and 18% before coating

2. Verify that preservative treatment has been applied where required (EN 351 use class) and allowed to dry completely

3. Check that the correct coating system is applied — primer, undercoat and finish coat per manufacturer's specification

4. Inspect for uniform coverage, smooth finish, no runs, sags or bare patches — sand between coats as required

5. Verify end-grain sealing on all exposed timber ends to prevent moisture ingress

- Coating applied to timber with excessive moisture content, causing blistering and peeling

- Missing preservative treatment on exterior timber, leading to fungal decay

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

- Insufficient sanding between coats resulting in poor inter-coat adhesion

According to EN ISO 2409 (cross-cut test) and EN ISO 2808 (film thickness), finished paintwork must demonstrate adequate adhesion, film build and visual quality. Inspection should be conducted in good lighting conditions (minimum 500 lux) at a viewing distance appropriate to normal use. The finish must be free from defects including runs, sags, curtains, brush marks, roller stipple, holidays (missed areas), blistering, flaking and colour variations. Portuguese RGEU requires that all finishes are executed to a workmanlike standard. Colour must match the approved sample or RAL/NCS reference within acceptable tolerance (ΔE ≤ 1.0 for critical areas).

1. Inspect all painted surfaces under adequate lighting (minimum 500 lux) at a normal viewing distance (1.5 m for walls, 0.5 m for joinery)

2. Check for visual defects — runs, sags, drips, brush marks, roller stipple, holidays, orange peel, blistering or flaking

3. Verify colour consistency against the approved sample or RAL/NCS reference — use a spectrophotometer for critical colour-matched areas

4. Perform cross-cut adhesion test (EN ISO 2409) on representative areas — classification 0 or 1 required

5. Measure dry film thickness on flat surfaces using a magnetic or eddy-current gauge to confirm adequate film build

- Visual defects visible under normal lighting conditions due to poor application technique

- Colour variation between walls or areas from different paint batches or inconsistent application

- Insufficient film thickness reducing durability and coverage

- Poor adhesion due to inadequate surface preparation or primer omission

Portuguese Decreto-Lei 181/2006, transposing EU Directive 2004/42/EC (Decopaint Directive), sets maximum VOC (Volatile Organic Compound) content limits for decorative paints and varnishes. Interior matt wall paints must not exceed 30 g/l VOC; interior gloss paints must not exceed 100 g/l; exterior masonry paints must not exceed 40 g/l. Products must display VOC content on the label. For green building certifications (LEED, BREEAM) and improved indoor air quality, lower-emission products may be specified. All paint containers on site must be checked for VOC labelling compliance before use.

1. Check paint container labels for VOC content declaration — must comply with D.L. 181/2006 maximum limits for the product subcategory

2. Verify VOC limits: interior matt walls ≤ 30 g/l, interior gloss ≤ 100 g/l, exterior masonry ≤ 40 g/l, interior trim/varnish per subcategory limits

3. Cross-reference product technical data sheets with the specification — confirm VOC class meets any additional project requirements (e.g. LEED, BREEAM)

4. Ensure adequate ventilation during and after application of all interior coatings — minimum requirements per manufacturer's data sheet

5. Retain documentation (labels, TDS, safety data sheets) for compliance records and building file

- Paint products exceeding D.L. 181/2006 VOC limits used on site without verification

- Missing VOC content declaration on product labels

- High-VOC products used internally without adequate ventilation, affecting indoor air quality

- Product substitutions on site introducing non-compliant VOC levels without approval