Houses and Apartments Waterproofed with EPDM for Life
EPDM for housing protects roofs, terraces, balconies and basements with a single installation for 50+ years — cold flame-free installation, 6% VAT on renovation works, 20-year guarantee and zero maintenance.
Waterproofing Problems in Residential Buildings
In Portugal, more than 60% of buildings were constructed before 1990 with waterproofing systems designed for a 15-20 year service life that have never been adequately replaced. The 2021 Census (INE) established that approximately 1.2 million dwellings showed moderate or major repair needs, with moisture cited as the most frequent cause. The typical response has been palliative: waterproof paints that fail in 2-4 years, mastic at visible joints, liquid bitumen over roofs. Each repair cycle creates a substrate of incompatible superimposed systems — and the problem returns worse than before.
- Bituminous house roof membrane replaces at 15-20 years — €5,000 to €15,000 per replacement, recurring throughout the owner's lifetime
- Apartment balconies commonly cause infiltrations to the apartment below — residents' disputes and legal claims under the Civil Code
- Basements without adequate waterproofing have permanent moisture, mould, radon in geological risk zones, and unusable space
- Portugal receives 2,500-3,000 hours of sunshine annually — double the UK — degrading bituminous membranes far faster than Northern European data sheets suggest
The EPDM Solution for Residential
EPDM for housing offers a definitive solution for roofs, terraces, balconies and basements. EPDM's saturated polymer chain is chemically inert to UV and ozone — its resistance is not depleted over time as happens with protective coatings. Vulcanisation creates a three-dimensional cross-linked network that maintains elasticity from -45°C to +150°C throughout the building's service life.
- House flat roof with EPDM — single installation for the entire home life, no anticipated replacement cycle
- Apartment balcony with EPDM — eliminates residents' disputes and fulfils the Civil Code conservation obligation
- Basement with exterior EPDM on walls and base slab — dry habitable space, with simultaneous radon protection in geological risk zones
- 6% VAT (Lista II-Verba 2.27 of the Código do IVA) on residential renovation works — saving €2,070 on a €15,000 project
EPDM Benefits
Definitive Protection — 50+ Years Field-Documented
A single EPDM installation protects housing for 50+ years — documented by the ERA study (membranes aged 28-32 years with retained elongation of 180-240%) and the SKZ study (median projected service life exceeding 50 years by Arrhenius methodology). Unlike paints (2-4 years) and bitumen (15-20 years), EPDM has no UV degradation mechanism: its saturated polymer backbone has no double C=C bonds to photooxidise.
6% VAT and Lower Total Cost of Ownership
Waterproofing works on residential buildings qualify for reduced 6% VAT (instead of 23%) under Lista II-Verba 2.27 of the Código do IVA — saving €2,070 on a €15,000 project and €5,520 on a €40,000 project with insulation included. Total EPDM cost of ownership over 50 years is significantly lower than bitumen when 2-3 replacements are included.
Zero Periodic Maintenance
EPDM requires no periodic painting, sealant reapplication, UV treatment or maintenance product of any kind. Membriko seams are sealed with pressure-activated butyl tape — they require no periodic resealing if correctly installed. Membriko recommends only annual visual inspection in October (check drains, parapets and any physical damage) and, after severe storms, checking for sharp metal debris.
Habitable Basements and Radon Protection
EPDM applied externally to basement walls and base slab creates a completely dry basement, transforming unusable space into habitable area. In geological radon risk zones (Beira Interior, Trás-os-Montes, Serra da Estrela), EPDM membrane is recognised by Portugal's DGS as an effective Rn-222 retention barrier (BRE 211, EN 13829).
Thermal Comfort and REH Energy Certificate
EPDM + PIR warm-roof installation improves the U-value from 2.0-3.0 W/m²K (uninsulated slab) to 0.18-0.22 W/m²K (100-120 mm PIR) — exceeding the REH requirement of 0.35 W/m²K by more than 37%. Indoor temperature reduction of 3-5°C in July-August for top-floor apartments. The improved Energy Performance Certificate is mandatory documentation for property sale and rental in Portugal.
Green Roof and Landscaped Terrace
For houses with flat roofs, FLL-certified EPDM (EN 13948) supports a garden, urban allotment or planted terrace — completely invisible beneath the planting substrate. Extensive green roofs (10-15 cm substrate) add 120-150 kg/m² to the slab; intensive (30+ cm) add 300-500 kg/m². Structural verification is mandatory. Membriko coordinates with a structural engineer when this configuration is specified.
Technical Specifications
Thickness (roof and terrace)
1.2 mm / 1.5 mm (standard) / 2.0 mm (green roof or intensive traffic)
Thickness (basement and balcony)
1.5 mm
Elongation at break
≥ 300%, typical 400-500% (EN 12311-2)
Service temperature
-45°C to +150°C
UV resistance (exposed)
Intrinsic — saturated backbone, no C=C double bonds
Freeze-thaw resistance
Excellent — glass transition temperature -60°C to -50°C
Green roof certification
FLL and EN 13948 (2.0 mm version)
Standard
EN 13956 Type 3 — CE marking
Installation Process
- 1
Diagnosis and Free Technical Visit
Home inspection: identification of zones to waterproof, substrate assessment (tap testing for tiled balconies, resistive moisture measurement for roofs), identification of active infiltrations. Membriko performs the technical visit at no cost and without obligation — the written report includes current condition assessment, recommended solution and indicative programme.
- 2
Main Roof
Substrate preparation. Decision: over-membrane installation (where substrate is sound and dry) or full strip-out (where moisture is trapped or existing waterproofing has delaminated). PIR thermal insulation installation (80-120 mm depending on U-value target). EPDM installation with flashings, gutters and singular points — no mastic as primary element on any singular point.
- 3
Balconies and Terraces
Balcony slab preparation. EPDM installation with wall upstands (minimum 150 mm above finish level). Drain treatment with EPDM or cast iron flange — membrane passes under the clamping ring, no exposed mastic on any drain. Prefabricated EPDM threshold flashing for the junction with the door frame. Final surfacing in ceramic, stone or composite decking on adjustable pedestals.
- 4
Basement and Foundations
For basements with exterior access: EPDM applied to positive (external) face of walls and base slab before backfilling — positive system of maximum effectiveness. For rehabilitation without exterior access: internal tanking system with mechanically anchored EPDM and perimeter drainage channel. In radon risk zones: integrated sub-slab ventilation geocomposite installation.
- 5
Singular Points and Full Continuity
All membrane penetrations — drainage pipes, electrical conduits, antenna masts, solar panel brackets, rooflights — receive prefabricated EPDM pipe boots or stainless steel pressure-ring collars. No singular point is sealed with bituminous mastic or silicone as primary element. Expansion joints treated with prefabricated EPDM profiles accommodating ±50 mm of movement.
- 6
Watertightness Test
Flood test (for accessible terraces and balconies — minimum 50 mm water level for 24 hours) or electronic leak detection (ELD) before covering the membrane with final surfacing. All singular points verified with metal probe. Without passing the test, no advancement to final surfacing.
- 7
Warranty, Documentation and Maintenance Plan
Issue of 20-year warranty per waterproofed zone, transferable on property sale. Technical dossier: membrane data sheets, photographic installation record, watertightness test result, and annual maintenance recommendations (visual inspection in October + drain verification). Membriko offers an optional annual maintenance contract.
- 8
Tax Documentation (6% VAT)
Membriko is a construction company registered with IMPIC and issues invoices at 6% VAT for all qualifying residential renovation projects under Lista II-Verba 2.27 of the Código do IVA. We provide clients with the documentation needed to support IRS tax deductions where applicable.
Installation Techniques
Warm Roof with EPDM over PIR Insulation
For flat or gently sloped roofs. Bonded or mechanically fastened EPDM over PIR insulation. Most durable residential roofing system on the market — combines 50+ year impermeability with REH-compliant thermal improvement.
Vantagens
- Service life exceeding bituminous roof (50+ years vs 15-20 years)
- Simultaneous U-value improvement — U = 0.22 W/m²K with 100 mm PIR (exceeds REH by 37%)
- Terrace or garden on the roof possible with FLL EPDM
- Cold installation — no flame, no fire risk near timber structures or pergolas
Desvantagens
- Higher initial cost than bitumen (offset by avoiding 2-3 replacements over 50 years)
- Flat roof aesthetic differs from pitched roof (may require planning permission in some municipalities)
Basement Rehabilitation with Exterior EPDM
For basements with chronic moisture where exterior access is available. Perimeter excavation, EPDM on exterior walls + drainage geocomposite + French drain + controlled backfill. Definitive dry basement solution.
Vantagens
- Basement goes from unusable damp space to habitable area — property value increase of €20,000-€50,000+
- Positive system — water blocked before contacting concrete
- Simultaneous radon protection in geological risk zones (BRE 211)
- Eliminates recurring chronic moisture costs (treatments, maintenance, damaged belongings)
Desvantagens
- Requires perimeter excavation — significant exterior works (1-2 weeks)
- Higher cost than interior solutions, but more effective and durable
Internal Tanking for Rehabilitation Without Excavation
For existing basements with infiltrations where exterior excavation is not feasible (terraced houses, adjacent buildings). EPDM mechanically anchored to the interior of walls and slab with perimeter drainage channel. Fully interior works.
Vantagens
- Fully interior works — no excavation, minimal disruption to occupants
- Applicable to terraced houses or with adjacent buildings where excavation is impossible
- Perimeter drainage channel as complementary safety system
- Combinable with sub-slab radon ventilation installation
Desvantagens
- Negative system — does not prevent water contacting concrete; manages entry
- Slight interior space reduction from air cavity (30-50 mm per wall)
Comparison with Other Membranes
| Característica | EPDM | SBS/APP bituminous felt | Plasticised PVC sheet | Liquid polyurethane (PU) |
|---|---|---|---|---|
| Documented service life (field data) | 50+ years (ERA: retained elongation 180-240% at 28-32 years) | 10-20 years in Portuguese climate (intense UV) | 15-25 years (plasticiser loss leads to cracking) | 5-10 years (recoating required) |
| UV resistance (Portugal — 2,500-3,000 sun hours/year) | Intrinsic — saturated backbone, no photooxidation mechanism | Poor — photooxidation at C=C bonds of SBS block | Good with intact plasticiser; degrades as plasticiser is lost | |
| Flame-free installation near timber structures | Yes — water-based adhesive, no torch | No — genuine fire risk near timber structures | Yes — but volatile solvents present | |
| Periodic maintenance | None — annual visual inspection only recommended | Annual recommended + replacement at 15-20 years | Mandatory recoating at 5-10 years | |
| Green roof certification (root resistance) | Yes — FLL and EN 13948 (2.0 mm version) | No — roots penetrate bitumen readily | Not recommended — roots and bitumen interface incompatible | |
| VAT applicable on residential renovation | 6% — Membriko issues invoice at reduced rate (IMPIC registered) | 6% reduced rate available for any system when contractor is registered |
Performance in the Portuguese Climate
Atlantic North (Minho, Douro Litoral — Humidity and Rain)
1,200-1,800 mm of annual rainfall in the northwest demands roofs with guaranteed impermeability under sustained wet conditions. Maintenance-free EPDM is the ideal solution for housing in northwest Portugal — especially for holiday homes unoccupied in winter, where nobody is present to detect early infiltration signs before they cause significant damage.
Interior (Trás-os-Montes, Beiras — Frost and Intense Heat)
Houses in the interior experience cold winters (frequent frost, temperatures below -5°C) and hot summers (roofs reaching 80-85°C in August). EPDM resists freeze-thaw cycling and surface temperatures of 150°C without degradation. In Trás-os-Montes and Beira Interior — geological radon risk zones — EPDM membrane simultaneously serves as waterproofing and DGS-recognised radon retention barrier.
South and Algarve (Second Homes and Tourism)
Non-permanent residential use in Algarve and Alentejo especially benefits from EPDM — waterproofing that functions without maintenance during extended periods of non-occupancy. Roofs reach 85-90°C in July-August; bitumen softens and flows under these conditions. For holiday homes with integrated pools or green roofs, FLL EPDM is the only system combining long-term impermeability with root resistance.
Lisbon and Porto (Condominiums and Urban Rehabilitation)
The pre-1990 residential stock of Lisbon and Porto historic centres has the highest concentration of bituminous roofing at end of service life. The EPDM over-membrane approach over existing bitumen is frequently the most economical solution — eliminating full removal and minimising condominium resident disruption. Membriko's technical documentation is formatted for presentation at Condominium Assembly, facilitating approval by qualified majority under Article 1427 of the Civil Code.
Coastal Zones (Chlorides and Marine Environment)
Homes and apartments in coastal locations — Costa Vicentina, Algarve, Costa da Prata — face marine chloride and salt humidity that degrades bituminous and PVC membranes far faster than inland. EPDM is completely inert to salt water and chloride solutions, maintaining waterproofing performance without accelerated degradation in coastal proximity.
Frequently Asked Questions
This depends on the condition of the tiles and the substrate beneath them. Where tiles are solidly adhered and the screed underneath is structurally sound and dry, Membriko can prepare the surface and apply EPDM over the existing system. Where hollow-sounding tiles are detected by tapping, or where moisture measurement identifies trapped moisture, Membriko recommends full strip-out before EPDM is applied. The diagnostic site visit determines the correct approach.
For those planning to stay in the house for 20+ years, EPDM has lower total cost of ownership than bitumen (no replacements over 50 years vs 2-3 with bitumen). For properties in high-UV zones (Alentejo, Algarve), the advantage is greater still because bitumen degrades much faster than most homeowners expect. Membriko's 20-year warranty and the 6% VAT rate make the decision clearer.
Yes, if applied externally with the correct system (EPDM + drainage geocomposite + French drain + controlled backfill). The positive exterior system blocks water before it contacts concrete — it is the most effective solution. For basements where exterior excavation is not feasible, internal tanking with mechanically anchored EPDM and perimeter drainage is an effective alternative, though less definitive than the external system.
Yes. With FLL-certified 2.0 mm EPDM (EN 13948 root resistance certification) and the appropriate drainage and substrate system, it is possible to create a garden, urban allotment or planted terrace. The critical consideration is the load-bearing capacity of the slab: extensive green roofs add approximately 120-150 kg/m². Membriko coordinates with a structural engineer to verify slab capacity when this configuration is specified.
The EPDM membrane itself has negligible thermal resistance. However, when installed as part of a warm-roof system over PIR insulation — standard Membriko practice for renovation projects — the combined system dramatically improves the roof U-value from 2.0-3.0 W/m²K (uninsulated slab) to 0.22 W/m²K with 100 mm PIR. This can contribute to an improvement of one to two EPC classes, with a direct impact on market value and rental yield.
The reduced 6% VAT rate (Lista II-Verba 2.27, Código do IVA) applies to works of conservation, maintenance, repair and renovation on residential buildings regardless of whether they are owner-occupied or rented, provided the building is at least two years old and works are carried out by a licensed contractor. Works on a shared building element (such as the building roof) managed by the condominium committee also qualify under the same conditions. Membriko is registered with IMPIC and issues invoices at the 6% rate for all qualifying projects.
A single-family home with a flat roof of 100-150 m² typically takes three to five working days from substrate preparation to completion, including the flood test and drain installation. More complex projects — multiple roof planes, simultaneous insulation, green roof, high numbers of singular points — may require seven to ten working days. Membriko provides a written day-by-day programme with every project quotation.
Membriko's 20-year warranty covers defects in materials and installation workmanship. If moisture ingress occurs during the warranty period, Membriko carries out a site investigation, identifies the cause and undertakes repair at no cost to the client if the defect falls within the warranty scope. The warranty is delivered as a formal written certificate at project handover — retained with property title documents, it has demonstrable legal and commercial value in any future sale or remortgage.
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