Waterproofing & Damp Protection

According to EN 13969 and EN 13967, the waterproofing membrane type must match the design specification and intended use (below-grade, wet rooms, terraces). LNEC ITE 34 provides Portuguese guidance on membrane selection for different exposure conditions. The RGEU requires adequate moisture protection for all habitable spaces.

1. Verify that the membrane product matches the specification in the project design documents (type, manufacturer, thickness)

2. Check CE marking and declaration of performance (DoP) against EN 13969 or EN 13967 requirements

3. Confirm the membrane class is appropriate for the water pressure expected (e.g. below-grade hydrostatic pressure vs splash zones)

4. Review LNEC ITE 34 recommendations for the specific application (foundations, terraces, bathrooms)

5. Verify that storage conditions on site have not degraded the membrane (UV exposure, temperature)

- Membrane type not matching the design specification or exposure class

- Missing or invalid CE marking and DoP documentation

- Membrane degraded due to improper on-site storage (sun exposure, folding damage)

- Incorrect membrane selected for below-grade applications with hydrostatic pressure

According to EN 13969 and LNEC ITE 34, the substrate must be clean, dry, smooth and free of sharp protrusions before membrane application. Concrete substrates should have a moisture content below 6% (by mass) and surface irregularities must not exceed 5 mm under a 2 m straightedge. Primers and bonding agents must be compatible with both membrane and substrate.

1. Measure substrate moisture content with a calibrated moisture meter — must be below the membrane manufacturer's specified maximum (typically under 6%)

2. Check surface flatness with a 2 m straightedge — deviations must not exceed 5 mm per LNEC ITE 34

3. Inspect the substrate for cracks, sharp edges, debris and standing water that could compromise adhesion

4. Verify that the specified primer or bonding agent has been applied at the correct coverage rate

5. Confirm that all penetrations (pipes, drains) have been prepared with appropriate collars or sleeves

- Substrate too wet, causing adhesion failure or blistering of the membrane

- Surface irregularities puncturing or tenting the membrane over time

- Primer omitted or applied unevenly, leading to delamination

- Unclean substrate with dust, oil or curing compounds preventing proper bond

- Penetrations not properly prepared before membrane installation

According to EN 13969 and EN 13967, membranes must be installed with minimum lap widths (typically 100 mm side laps, 150 mm end laps) and all joints must be fully sealed. LNEC ITE 34 specifies that torch-applied bituminous membranes must achieve full fusion at laps. Liquid-applied systems must meet the minimum dry film thickness stated in the product standard.

1. Measure lap widths at multiple locations — side laps minimum 100 mm, end laps minimum 150 mm per EN 13969

2. Inspect all lap joints for continuity of seal — probe with a blunt tool to check for unbonded areas

3. For torch-applied membranes, verify that bitumen squeeze-out is visible at all lap edges (indicating full fusion)

4. For liquid-applied systems, measure wet and dry film thickness at representative points

5. Confirm that the membrane extends to the required height above finished floor level (minimum 150 mm for wall upstands)

6. Check that all T-joints and cross-laps have been properly reinforced with additional membrane patches

- Insufficient lap width causing water ingress at joints

- Incomplete fusion of torch-applied laps (cold spots)

- Liquid membranes applied too thin, failing to achieve minimum thickness

- Upstand height insufficient, allowing water bypass above the membrane

- T-joints not reinforced with additional patches

According to LNEC ITE 34 and EN 13969, all penetrations, corners, movement joints and changes of plane require reinforced detailing. Pipe penetrations must use proprietary collars or be sealed with compatible sealant and additional membrane reinforcement. Internal and external corners must have fillet strips and additional membrane layers per manufacturer guidance.

1. Inspect all pipe and service penetrations for proper collar installation or sealant application with membrane overlap

2. Check internal corners for fillet strips (minimum 50 mm radius or chamfer) and additional membrane reinforcement layers

3. Verify external corners have additional reinforcement strips extending minimum 150 mm each way

4. Inspect movement joints for correct detailing with flexible membrane loops or proprietary joint covers

5. Check drain and outlet connections for clamping rings and membrane dressed into the drain body

- Pipe penetrations sealed with incompatible sealant that cracks or detaches over time

- Missing fillet strips at internal corners causing membrane bridging and stress cracking

- Movement joints not detailed with flexible loops, leading to membrane rupture

- Drain connections not clamped, allowing water to bypass into the structure

According to LNEC ITE 34, waterproofing membranes in below-grade and terrace applications must be protected from mechanical damage by a protection layer (geotextile, protection board or screed). For below-grade walls, a drainage composite (dimpled sheet per EN 13252) should be installed outboard of the protection layer to relieve hydrostatic pressure per RGEU requirements.

1. Verify that a protection layer (geotextile, XPS board or protection screed) has been installed over the membrane before backfilling or paving

2. Check that the protection board is continuous and joints are taped or overlapped to prevent screed intrusion

3. For below-grade applications, confirm that a drainage composite (dimpled membrane) is installed with dimples facing the wall

4. Verify that the drainage layer connects to the perimeter drain at foundation level

5. Check that backfill material is free of sharp stones or debris that could puncture the membrane through the protection layer

- Protection layer omitted, leading to membrane puncture during backfilling

- Drainage composite installed with dimples facing wrong direction

- Backfill material containing sharp rubble that damages the membrane despite protection

- Drainage layer not connected to the perimeter drain, rendering it ineffective

According to LNEC ITE 34 and RGEU, completed waterproofing must be tested before concealment. Flood testing of flat roofs and wet areas should maintain a minimum 50 mm water depth for 24–48 hours. Spray testing of vertical surfaces should follow a systematic pattern. All test results must be documented with photographs and signed records.

1. For flat areas (terraces, wet rooms), carry out a flood test with minimum 50 mm water depth maintained for 24 hours — inspect soffit below for any signs of moisture

2. For vertical or sloped surfaces, conduct a spray test starting from the lowest point upward, holding the spray for minimum 5 minutes per section

3. Use infrared thermography to detect hidden moisture paths that may not be visible during initial testing

4. Record all test results with photographs, date, duration, water depth and inspector signature

5. Re-test any repaired areas after remedial work has been completed and cured

- Flood test duration too short to reveal slow leaks

- Drains not properly plugged during flood testing, giving false positive results

- Spray test not systematic (starting from top instead of bottom, masking the leak source)

- Test results not documented, making it impossible to verify compliance later

- Repairs not re-tested after remedial work

According to EN 13969, EN 14909 and RGEU, a damp-proof course must be installed at the base of all masonry walls to prevent rising damp. The DPC must be set minimum 150 mm above external finished ground level. In Portugal, the RGEU requires all ground-floor constructions to have effective damp protection separating the structure from the ground.

1. Verify that a DPC has been installed at the base of all external and internal masonry walls

2. Measure the height of the DPC above external finished ground level — minimum 150 mm per EN 13969

3. Check that the DPC extends the full width of the wall and projects slightly beyond the external face

4. Verify continuity at corners, junctions and door thresholds — laps minimum 100 mm and sealed

5. Confirm that the DPC is not bridged by render, mortar droppings or ground levels built up after installation

- DPC set too low, below the minimum 150 mm above finished ground level

- DPC bridged by external render carried below the DPC line

- Mortar droppings on the cavity tray bridging the DPC and allowing moisture transfer

- DPC missing at door thresholds or internal wall junctions

- Ground level raised after construction, placing the DPC below grade