Waterproofing Inspection

Per EN 1504-10 and EN 13707, substrates receiving waterproofing membranes must be clean, dry, smooth, and free of sharp protrusions. Concrete substrates shall have a moisture content below the membrane manufacturer's stated limit. Surface regularity must comply with the specified tolerances, and any defects such as honeycombing or cracks must be repaired prior to membrane application.

1. Verify substrate is free of dust, oil, laitance, and loose material per EN 1504-10

2. Measure substrate moisture content with a calibrated moisture meter — confirm it is within manufacturer limits

3. Check surface regularity with a 2m straight edge — deviations typically must not exceed 5mm

4. Confirm all cracks and voids have been filled and smoothed with appropriate repair materials per EN 1504-3

5. Verify that required primers have been applied at the correct coverage rate and allowed to cure

- Substrate too wet at time of membrane application, leading to blistering

- Laitance or dust not removed, causing poor adhesion

- Sharp edges or protrusions puncturing membranes after installation

- Primer omitted or applied at insufficient coverage

Per EN 13969, flexible bituminous sheets used as damp proof courses below grade must resist hydrostatic pressure appropriate to the site conditions. EN 14967 specifies characteristics for flexible sheets used as underlays in below-grade applications. Membrane type and grade must match the water table level, soil conditions, and structural movement expectations as determined by the geotechnical report.

1. Confirm membrane type and grade match the design specification and are appropriate for the water table level per EN 13969

2. Verify laps are correctly dimensioned — minimum 100mm side laps and 150mm end laps for bituminous sheets

3. Check that membrane is carried up above finished ground level by at least 150mm

4. Inspect protection board or drainage layer installation over the membrane to prevent mechanical damage

5. Verify continuity at all construction joints and confirm joint sealing per EN 13969 requirements

6. Check that drainage provisions (EN 13252 drainage geocomposites) are installed where specified

- Membrane grade insufficient for actual hydrostatic pressure conditions

- Laps too narrow or poorly sealed, creating water ingress paths

- Membrane damaged during backfilling without adequate protection

- No drainage layer installed, increasing hydrostatic pressure on the membrane

- Membrane not extended above ground level, allowing water bridging

Per EN 14891, liquid applied water-impermeable products used beneath ceramic tiling in internal wet areas must demonstrate watertightness and adhesion to the substrate. EN 1504 covers liquid applied systems for concrete protection. Application must achieve the manufacturer's specified dry film thickness (DFT), and reinforcement fabric must be embedded at changes of plane and over joints.

1. Verify the product is certified to EN 14891 and the correct class is specified (CM, DM, or RM)

2. Check wet film thickness during application using a wet film gauge — confirm it will achieve required DFT

3. Confirm reinforcement fabric is embedded at all internal corners, floor-wall junctions, and pipe penetrations

4. Verify minimum two coats applied with second coat at right angles to the first

5. Check curing time between coats has been observed per manufacturer's instructions

6. Perform adhesion test on a sample area — minimum 0.5 N/mm² per EN 14891

- Insufficient film thickness resulting in pinholes and water transmission

- Reinforcement fabric omitted at critical junctions and corners

- Second coat applied before first coat has adequately cured

- Product applied in temperatures outside the manufacturer's recommended range

Per EN 13707, reinforced bitumen sheets for roof and structural waterproofing must meet specified tensile strength, elongation, and watertightness requirements. EN 13956 covers plastic and rubber sheet membranes (PVC, TPO, EPDM), specifying thickness, tensile properties, and dimensional stability. Sheets must be installed with correct lap widths and joint welding or adhesion methods as specified.

1. Verify membrane product matches specification and holds valid CE marking per EN 13707 or EN 13956

2. Check membrane thickness with a calibrated gauge — minimum thickness per design (typically 1.5mm for single-ply)

3. Inspect all laps — minimum 80mm for welded plastic/rubber sheets, 100mm for bituminous sheets

4. Test weld seams using a blunt probe or vacuum box test for continuity

5. Verify that membranes are mechanically fastened, adhered, or ballasted as specified in the design

- Membrane thickness below specification due to stretching during installation

- Weld seams incomplete or cold-welded, creating leak paths

- Inadequate lap widths at sheet joints

- Membrane not adequately secured against wind uplift forces

- Incompatible materials in contact causing chemical degradation

Per EN 14891, liquid applied membranes used in wet rooms (bathrooms, showers, kitchens) must provide a continuous waterproof barrier on floors and walls to the required height. EN ISO 13788 addresses internal surface condensation risks and interstitial condensation in wet room constructions. The waterproofing system must be tanked to a minimum height of 1.8m in shower areas and 300mm elsewhere unless national requirements specify otherwise.

1. Verify waterproofing membrane is applied to the full shower area floor and walls to minimum 1.8m height per EN 14891

2. Confirm membrane is turned up walls by at least 300mm outside the direct wet zone

3. Check that all pipe penetrations are sealed with manufacturer-approved collars or flanges

4. Inspect floor waste/drain connection — membrane must be clamped into the drain flange

5. Verify membrane overlap at sheet joints is minimum 50mm with proper sealing

6. Confirm a flood test has been performed (minimum 24 hours) with water level at 25mm below the lowest overflow

- Membrane not carried high enough on walls in shower zones

- Pipe penetrations not sealed with proprietary collars, creating leak points

- Drain connection not properly clamped, allowing water under the membrane

- Membrane damaged by subsequent trades before tiling commences

- No flood test performed to verify watertightness before tiling

Per EN 13707, all joints, laps, and penetrations in waterproofing membranes must be detailed to maintain continuous watertightness. EN 1928 provides test methods for determining the watertightness of completed assemblies. Movement joints must accommodate structural movement without compromising the membrane. All penetrations (pipes, cables, fixings) must be sealed with compatible proprietary details.

1. Inspect all membrane laps for correct width and continuous bonding per EN 13707

2. Verify movement joints are formed with flexible membrane strips allowing specified movement range

3. Check pipe and cable penetrations for proprietary sealing collars or boots correctly installed

4. Confirm that no fixings penetrate the waterproofing layer without appropriate sealing

5. Inspect upstand terminations — membrane must be chased into walls or terminated with a clamping bar above the waterline

- Laps peeling open due to insufficient bonding or contaminated surfaces

- Movement joints too rigid, causing membrane tearing at structural movement points

- Penetrations sealed with incompatible sealant instead of proprietary collars

- Fixings driven through the membrane by subsequent trades without resealing

- Upstand terminations too low, allowing water to bypass the membrane

Per EN 1928, the watertightness of flexible sheet membranes shall be verified by standardised test methods including hydrostatic pressure testing. Flood testing for wet rooms and flat roofs provides in-situ verification of the completed waterproofing system. All tests must be documented and results must demonstrate compliance with the specified performance requirements before subsequent works proceed.

1. Perform flood test on flat roofs and wet rooms — maintain water at specified depth for minimum 24 hours per EN 1928 principles

2. Use electronic leak detection (ELD) or spark testing for single-ply membranes to locate defects

3. Conduct infrared thermography survey on completed roof membranes to identify trapped moisture

4. Review all test certificates and delivery notes for membrane products confirming EN compliance

5. Verify that a photographic record of all concealed waterproofing has been made before covering

6. Confirm all test results are documented in the inspection and test plan (ITP)

- Flood test not performed or duration too short to identify slow leaks

- Electronic leak detection not carried out on single-ply roof membranes

- No photographic record of concealed waterproofing details before covering

- Test results not documented or filed in the quality records

- Subsequent works commenced before test results confirmed acceptable