Tiling Inspection

Per EN 14411 installation guidance, substrates must be flat within 3mm measured under a 2m straight edge for wall tiles and 2mm for floor tiles with rectified edges. Substrate moisture content must be within limits specified by the adhesive manufacturer. Concrete substrates must have cured for a minimum of 28 days, and screeds must have reached adequate strength. Plasterboard substrates must be Type H1 or H2 per EN 520 in wet areas.

1. Check substrate flatness with a 2m straight edge — maximum 3mm deviation for standard tiles, 2mm for large format

2. Measure substrate moisture content with a calibrated meter — typically below 4% CM for cementitious screeds

3. Verify screed has achieved adequate strength — minimum 15 N/mm² for normal traffic areas

4. Confirm substrate is clean, free of laitance, dust, and contaminants that impair adhesion

5. Check that appropriate primer has been applied where specified by the adhesive manufacturer

- Substrate out of tolerance, causing excessive adhesive bed thickness or lippage

- Screed too wet, preventing proper adhesive bond formation

- Laitance not removed from concrete substrates, causing adhesion failure

- Wrong substrate in wet areas (standard plasterboard instead of moisture-resistant type)

Per EN 12004, tile adhesives are classified by type and performance: C1 (normal cementitious), C2 (improved cementitious with additional characteristics), with deformability classes S1 (deformable) and S2 (highly deformable). Class C2S1 or C2S2 is required for large format tiles, external use, and substrates subject to movement. Minimum adhesive coverage on the back of the tile must be 65% for walls and dry floors, and 95% for wet areas and external applications.

1. Verify adhesive class matches the specification and is certified to EN 12004 — check bag/bucket markings

2. Confirm correct notched trowel size is used for the tile format (e.g., 10mm or 12mm notch for large tiles)

3. Check adhesive coverage by periodically lifting a freshly laid tile — verify minimum coverage is achieved

4. Confirm back-buttering is performed on large format tiles (any dimension over 300mm)

5. Verify adhesive open time is not exceeded — tiles must be placed while adhesive is still tacky

6. Check adhesive bed thickness is within manufacturer's limits (typically 3–15mm for thick-bed adhesives)

- Wrong adhesive class for the application (e.g., C1 used externally instead of C2S1)

- Insufficient adhesive coverage causing hollow spots and potential tile cracking

- Adhesive open time exceeded, resulting in poor bond (skinning on surface)

- Notched trowel too small for the tile format, giving inadequate bed thickness

Per EN 14411, ceramic tiles must meet dimensional tolerances for length, width, straightness of edges, and rectangularity. Lippage (step between adjacent tiles) must be controlled — typically maximum 1mm for rectified tiles and 2mm for non-rectified tiles. Expansion joints must be provided at maximum 4.5m intervals internally and 3m externally, at all changes of plane, and at junctions with other materials.

1. Check tile alignment and lippage with a straight edge and feeler gauge — maximum lippage per specification

2. Verify consistent joint widths using spacers appropriate to tile format (minimum 2mm for wall, 3mm for floor)

3. Confirm expansion joints are positioned at all perimeters, changes of plane, and at specified intervals

4. Check tile layout for symmetry and minimal cuts — no tile piece smaller than half a tile at edges

5. Verify tiles are level across the floor surface — maximum 2mm under a 2m straight edge for rectified tiles

- Excessive lippage between tiles due to substrate irregularity or poor laying technique

- Expansion joints omitted, causing tile tenting or cracking from thermal/structural movement

- Inconsistent grout joint widths giving an uneven appearance

- Poor layout with thin tile cuts at visible edges

Per EN 13888, grout is classified as CG (cementitious grout) or RG (reaction resin grout). CG grouts are further classified as CG1 (normal) or CG2 (improved, with reduced water absorption and higher abrasion resistance). RG grouts (epoxy-based) are required for chemical resistance in industrial areas. Joint widths must be appropriate to the tile format and grout type, with minimum widths of 2mm for calibrated tiles and 5mm for rustic tiles.

1. Verify grout type and class match the specification per EN 13888 — CG2 minimum for wet areas

2. Check grout is fully compacted into joints with no voids or pinholes

3. Confirm joint widths are consistent and appropriate for the tile format

4. Verify expansion joints are filled with flexible sealant, not grout

5. Check grout colour consistency across the installation

6. Confirm grouted surface has been cleaned and excess grout removed before hardening

- Grout voids and pinholes allowing water penetration, especially in wet areas

- Expansion joints grouted instead of sealed with flexible sealant, causing cracking

- Wrong grout type — CG1 used in wet areas instead of CG2 or RG

- Inconsistent grout colour due to varying water content or application technique

Per EN 14891, liquid applied water-impermeable products used beneath ceramic tiling must achieve the required watertightness class (CM, DM, or RM). The membrane must be applied continuously with minimum overlap of 50mm at sheet joints and minimum upstand heights of 1.8m in shower areas and 300mm elsewhere. Reinforcement tape must be embedded at all internal corners, floor-wall junctions, and around penetrations.

1. Verify the waterproofing product is classified per EN 14891 and matches the specification

2. Confirm membrane is applied to the full extent of wet areas with correct upstand heights

3. Check reinforcement tape is embedded at all internal corners and floor-wall junctions

4. Verify overlap widths at membrane joints — minimum 50mm

5. Inspect pipe penetrations for proprietary sealed collars or boots

6. Confirm flood test has been performed and documented before tiling commences

- Waterproofing omitted from wet areas, relying solely on grout (which is not waterproof)

- Reinforcement tape not used at corners, leading to cracking and leaks

- Upstand height insufficient in shower areas

- No flood test performed before tiling, concealing membrane defects

Per EN 14411, tiles used externally must meet frost resistance requirements (water absorption group BIa or BIb, typically less than 3%). Slip resistance must comply with EN 16165 (formerly CEN/TS 16165) using the pendulum test method, with minimum PTV values set by national regulations. Adhesive must be class C2S1 or C2S2 per EN 12004 to accommodate thermal movement, and drainage falls must be a minimum of 1.5% to prevent standing water.

1. Verify tile water absorption classification per EN 14411 — must be Group BIa or BIb for frost resistance

2. Check slip resistance test results per EN 16165 — minimum PTV 36 for external level surfaces

3. Confirm adhesive is class C2S1 or C2S2 per EN 12004 for external applications

4. Verify adhesive coverage is minimum 95% on tile backs (back-buttering required)

5. Check drainage falls — minimum 1.5% away from the building

6. Confirm expansion joints at maximum 3m intervals and at all changes of plane

- Tiles not frost resistant, leading to surface spalling after freeze-thaw cycles

- Inadequate slip resistance creating a safety hazard when wet

- Insufficient adhesive coverage causing frost damage from trapped water

- Drainage falls too shallow, allowing standing water and freeze-thaw damage

- Expansion joints too widely spaced for external thermal movement