Waterproofing: Types & Pros/Cons

Waterproofing: Types, Pros/Cons & % Costs

Main types & where they fit

1. Bituminous Torch-On Membranes (SBS/APP)
   Best for: flat roofs, terraces, planters, podiums.
   Pros: proven, forgiving on substrates, good UV with mineral cap.
   Cons: hot works, laps depend on workmanship, heavier build-up.
2. Self-Adhesive Bituminous Membranes
   Best for: no-flame sites, detailing, sensitive substrates.
   Pros: cold-applied, safer than torching, clean laps.
   Cons: substrate must be very smooth/primed; lower peel if poorly rolled.
3. Single-Ply Sheets (TPO / PVC / EPDM)
   Best for: large roofs, lightweight systems.
   Pros: fast, light, clean seams (hot-air weld for TPO/PVC), good UV.
   Cons: needs trained installers; puncture protection at terraces; PVC dislikes bitumen contact without separation layer.
4. Liquid-Applied PU/PMMA/Polyurea Membranes
   Best for: complex details, balconies, wet areas, refurb overlays.
   Pros: seamless, excellent around penetrations, fast cure (PMMA/polyurea).
   Cons: substrate prep critical; some systems need topcoat/UV protection; odor/safety management.
5. Cementitious (Rigid/Flexible) & Crystalline Slurries
   Best for: tanks, basements (negative/positive side), wet rooms under tile.
   Pros: bonds to damp mineral substrates; negative-side options (from inside).
   Cons: rigid grades don’t bridge cracks; flexible grades need mesh/reinforcement at corners.
6. Bentonite (Sodium Bentonite Geocomposites)
   Best for: below-grade external wraps/blind-side against shoring.
   Pros: self-sealing around penetrations; tolerant to minor damage.
   Cons: needs confinement; performance affected by contaminated water/salts if not specified correctly.
7. Acrylic/Hybrid Liquid Coatings
   Best for: light duty roofs, refurb over sound membranes.
   Pros: easy, reflective, low-odor.
   Cons: lower puncture resistance; ponding water can shorten life unless rated.

Advantages & disadvantages (at a glance)

• Bituminous torch-on: + robust, multilayer redundancy | − hot works, weight.
• Self-adhesive bitumen: + no flame | − substrate perfection needed.
• Single-ply (TPO/PVC/EPDM): + lightweight, fast, UV-stable | − puncture risk, needs trained welding.
• Liquid PU/PMMA/polyurea: + seamless on complex details, rapid cure | − prep-sensitive; some need UV topcoat.
• Cementitious/crystalline: + works on damp concrete, negative-side options | − limited crack bridging (rigid types).
• Bentonite: + self-healing below grade | − requires confinement and correct chemistry.
• Acrylic/hybrid: + easy, reflective | − not for heavy traffic/pooling unless system-rated.

Material price differences (percentages only; baseline = Torch-On Bituminous Membrane = 0%)

(Indicative deltas for comparable quality systems; actuals vary by thickness, reinforcement, brand, warranty term.)

• Self-Adhesive Bituminous: +10–25% vs baseline
• Single-Ply TPO: +15–35% vs baseline
• Single-Ply PVC: +10–30% vs baseline
• Single-Ply EPDM: +0–20% vs baseline
• Liquid PU (aromatic, with topcoat): +5–25% vs baseline
• PMMA (rapid-cure, fleece-reinforced): +30–60% vs baseline
• Polyurea (spray, high-performance): +40–80% vs baseline
• Cementitious Flexible (2-comp): −10% to +10% vs baseline (range depends on coverage rates)
• Crystalline Slurry (negative/positive): −20–0% vs baseline
• Bentonite GCL (below grade): +0–20% vs baseline
• Acrylic/Hybrid Roof Coatings: −25–0% vs baseline (light-duty systems)

Selection tips (practical)

• Complex details/retrofit: go liquid PU/PMMA.
• Large lightweight roofs: go single-ply (TPO/PVC/EPDM) with protection where trafficked.
• Below grade/basements: pair bentonite or crystalline with proper drainage.
• Tile over wet rooms/balconies: use cementitious flexible or PU under tile.
• High durability & redundancy: multilayer bituminous or PMMA system.

Key risks & how to avoid them

• Poor substrate prep (all): leads to blisters/peel. Fix: moisture tests, primers, correct screed falls.
• Trapped moisture: blistering under dark membranes. Fix: dry-back checks, venting layers where needed.
• Wrong detailing at upstands/drains: leaks start at edges/penetrations. Fix: preformed corners, fleece reinforcement, metal terminations.
• UV & traffic: some liquids/bitumen need topcoat/protection. Fix: UV coats, tiles/pavers on pedestals where used as terrace.
• Compatibility: PVC vs bitumen, fresh PU over damp, etc. Fix: separation layers/primers per manufacturer.

One-line FAQ

• Can I waterproof over existing membranes? Often yes—if adhesion/compatibility are proven (pull tests) and detailing is upgraded.
• Which for ponding water? TPO/PVC, PMMA, or polyurea systems rated for standing water; acrylics only if certified.
• Trafficable terrace? Use membranes with protection layers (tiles on pedestals, screed, or wear coats).

Dacă vrei, fac o versiune scurtă “compare card” pentru site (iconițe + 3–4 bullets) și pot integra și procentele direct într-un tabel compact.