Wall & Floor Tiling

According to EN 12004 and RGEU, the substrate for tiling must be structurally sound, flat, clean and dimensionally stable. Flatness tolerance should be within 3 mm under a 2 m straightedge for thin-bed adhesive application and 10 mm for thick-bed. Concrete substrates must have cured for a minimum of 28 days and screeds for a minimum of 14 days. Moisture content must not exceed the adhesive manufacturer's limits.

1. Check substrate flatness with a 2 m straightedge — maximum 3 mm deviation for thin-bed adhesive, 10 mm for thick-bed

2. Measure substrate moisture content with a calibrated meter — must be below the adhesive manufacturer's maximum (typically 2–3% CM for cementitious screeds)

3. Tap the substrate to check for hollow or debonded areas in existing renders or screeds

4. Verify the substrate is free of dust, oil, paint, curing compounds and other contaminants

5. Confirm that movement joints in the substrate are mapped and will be carried through the tile finish

- Substrate too uneven for thin-bed adhesive, requiring excessive adhesive thickness

- Excessive moisture in green screeds causing adhesive failure

- Hollow or debonded screed areas not identified before tiling

- Movement joints in the substrate not continued through the tile layer

According to EN 12004, tile adhesives are classified by type (C — cementitious, D — dispersion, R — reaction resin) and class (1 — normal, 2 — improved) with additional characteristics (F — fast setting, T — slip resistant, E — extended open time, S1/S2 — deformable). The adhesive class must match the substrate type, tile format and exposure conditions. For external applications and large-format tiles (≥ 60 × 60 cm), a minimum C2TE S1 adhesive is required. Portuguese practice following LNEC recommendations requires deformable adhesives (S1 or S2) for heated floors and facades.

1. Verify adhesive product matches the specification — check CE marking, EN 12004 classification and declaration of performance (DoP)

2. Confirm the adhesive class is suitable for the application: C2TE S1 minimum for external, large-format tiles and heated floors

3. Check adhesive mixing ratio and consistency — must follow manufacturer's data sheet exactly

4. Measure adhesive bed thickness using a notched trowel appropriate to the tile size (e.g. 10 mm notch for tiles ≥ 40 cm)

5. Verify open time has not been exceeded — press a tile and lift to confirm ≥ 90% transfer of adhesive to tile back

- Adhesive class insufficient for the application (e.g. C1 used externally instead of C2 S1)

- Open time exceeded before tile placement, resulting in skinning and poor bond

- Incorrect trowel notch size leading to insufficient adhesive coverage

- Adhesive mixed with wrong water ratio, reducing bond strength and workability

According to EN 14411 and Portuguese RGEU requirements, tiles must be laid with consistent joint widths, proper alignment and adequate adhesive coverage. Back-buttering is required for large-format tiles (≥ 60 × 60 cm) to achieve minimum 95% adhesive coverage externally and 80% internally. Lippage between adjacent tiles must not exceed 1 mm for rectified tiles or 2 mm for non-rectified tiles. Expansion joints must be provided at perimeters, changes in substrate plane and at maximum 20–25 m² intervals for internal floors, and 9–12 m² for external areas, following LNEC guidance.

1. Check joint widths are consistent and match the specification — use wedge gauges to measure; minimum 2 mm for rectified tiles, 3–5 mm for non-rectified

2. Verify lippage between adjacent tiles using a straightedge — must not exceed 1 mm (rectified) or 2 mm (non-rectified)

3. Tap tiles with a hollow-sound tool to check adhesive coverage — no hollow sound indicates full contact; hollow areas indicate voids

4. Confirm expansion joints are provided at all perimeters, columns, doorways and at maximum intervals per specification

5. Check overall plane flatness with a 2 m straightedge — maximum deviation ±2 mm for premium finish

- Hollow tiles due to insufficient adhesive coverage or exceeded open time

- Inconsistent joint widths causing visual defects

- Missing or incorrectly positioned expansion joints, leading to tile tenting or cracking

- Excessive lippage between adjacent tiles creating trip hazards on floors

According to EN 13888, grout is classified as CG (cementitious) or RG (reaction resin), with classes 1 (normal) and 2 (improved), and optional characteristics W (reduced water absorption) and Ar (abrasion resistant). Grout type must match the application — CG2 WA minimum for wet areas and external tiling. Reaction resin grouts (RG) are required for chemically aggressive environments. Joints must be completely filled to the full depth of the tile. Portuguese practice requires epoxy or improved grouts in commercial kitchens and food preparation areas per hygiene regulations.

1. Verify grout product matches the specification — check CE marking, EN 13888 classification and suitability for the exposure conditions

2. Inspect joints to confirm they are fully filled to the tile face with no voids, pinholes or low spots

3. Check grout colour consistency across the installation — variations indicate mixing or application problems

4. Verify movement joints (expansion joints) are NOT grouted but sealed with appropriate flexible sealant

5. Confirm grout has been properly cleaned from tile surfaces before final setting

- Joints not fully filled, allowing water ingress and reducing tile stability

- Incorrect grout type for wet areas (e.g. CG1 used instead of CG2 W in showers)

- Expansion joints filled with rigid grout instead of flexible sealant, causing cracking

- Grout haze or residue left on tile surfaces due to inadequate cleaning

- Colour variation from inconsistent mixing or application timing

According to EN 14891 (liquid-applied waterproofing) and LNEC ITE 34, waterproofing membranes must be applied beneath tiles in all wet areas (bathrooms, showers, kitchens, balconies) before tiling commences. The membrane must extend a minimum of 200 mm above the finished floor level on walls in wet zones, and to full height in shower areas. RGEU requires all habitable spaces to be protected from moisture ingress. Membrane overlaps must be minimum 50 mm, and all corners and pipe penetrations must be reinforced with pre-formed sealing tape or fleece strips.

1. Verify waterproofing membrane type and product match the specification — check CE marking per EN 14891 or relevant membrane standard

2. Confirm membrane coverage extends to the required height on walls (200 mm minimum general wet areas, full height in showers)

3. Inspect all internal corners, floor-wall junctions and pipe penetrations for reinforcing tape or fleece band application

4. Check membrane overlap widths — minimum 50 mm at all joints

5. Perform a flood test (minimum 24 hours at 10 mm depth) on shower trays and wet room floors before tiling

- Waterproofing membrane omitted or applied only partially in wet areas

- Insufficient membrane height on walls, allowing water ingress behind tiles

- Corners and penetrations not reinforced, creating weak points for leaks

- Membrane damaged during subsequent trades before tiling commences

According to EN 14411 and CEN/TS 16165, floor tiles must meet slip resistance requirements appropriate to the intended use. The pendulum test (EN 13036-4) is the reference method in Portugal, with PTV ≥ 36 required for dry internal areas and PTV ≥ 45 for wet areas and external paving. The DIN 51130 ramp test (R-value classification R9–R13) is also used for industrial and commercial applications. Portuguese D.L. 163/2006 (accessibility regulations) requires slip-resistant floor surfaces in public buildings. Tiles in swimming pool surrounds and shower areas require barefoot classification per DIN 51097 (A, B or C).

1. Verify tile slip resistance classification from the manufacturer's DoP and technical data sheet — must match the specification for the intended use area

2. Check that PTV values or R-values are documented and appropriate: PTV ≥ 36 for dry internal, PTV ≥ 45 for wet zones

3. Confirm barefoot classification (A, B or C per DIN 51097) is provided for pool surrounds and wet barefoot areas

4. Verify that the installed tiles match the approved samples and specified product — substitutions may have different slip properties

5. Where required, arrange for on-site pendulum testing (EN 13036-4) to verify in-situ slip resistance meets the specification

- Tiles with insufficient slip resistance installed in wet areas or external paving

- Manufacturer's slip resistance data not available or not verified before installation

- Tile substitution during construction resulting in lower slip resistance than specified

- Polished or glazed tiles used in areas where higher slip resistance is required

- Cleaning products or sealants altering tile surface slip properties after installation