# Waterproofing Systems

## Waterproofing vs Dampproofing

### Definitions
| Type | Description | Use |
|------|-------------|-----|
| Dampproofing | Moisture resistance, not hydrostatic | Soil moisture, no water table |
| Waterproofing | Full barrier against water pressure | Below water table, planters |

### When Waterproofing Required
- Habitable space below grade
- High water table
- Planter boxes and green roofs
- Below-grade parking
- Tunnels and subway structures
- Swimming pools

---

## Below-Grade Systems

### System Types
| Type | Description | Cost |
|------|-------------|------|
| Fluid-applied membrane | Spray or roll applied | $$ |
| Sheet membrane | Self-adhered or loose-laid | $$$ |
| Bentonite | Clay panels, expands when wet | $$ |
| Cementitious | Crystalline/capillary | $$ |
| Drainage board | HDPE with fabric | $ (additive) |

### Sheet Membranes
| Product Type | Thickness | Temperature |
|--------------|-----------|-------------|
| Modified bitumen | 60-120 mil | Cold applied |
| HDPE | 40-60 mil | Varies |
| EPDM | 45-60 mil | Adhesive |
| PVC | 40-80 mil | Heat welded |

### Fluid-Applied
| Type | Description | Use |
|------|-------------|-----|
| Hot-applied rubberized asphalt | Seamless, self-healing | Below-grade walls |
| Cold fluid-applied | Elastomeric | Complex geometry |
| Spray polyurea | Fast cure, seamless | Large areas |

---

## Foundation Waterproofing

### Typical Assembly
```
Interior to exterior:
1. Concrete wall
2. Primer (if required)
3. Waterproof membrane
4. Protection board
5. Drainage board (dimpled)
6. Filter fabric
7. Drainage stone
8. Perimeter drain
9. Backfill
```

### Critical Details
| Location | Treatment |
|----------|-----------|
| Wall-to-footing | Cove or fillet |
| Penetrations | Pipe boots, sealant |
| Construction joints | Waterstop or membrane |
| Tie holes | Grout and membrane |
| Inside corners | Additional ply |
| Outside corners | Additional ply |

### Drainage System
| Component | Requirement |
|-----------|-------------|
| Drain pipe | 4" perf. PVC, filter fabric |
| Gravel backfill | 12" wide min, to surface |
| Drain board | Full height of wall |
| Discharge | Daylight, sump, or storm |

---

## Plaza and Podium Deck

### System Components
```
Top to bottom:
1. Pavers or topping
2. Pedestal/setting bed
3. Protection mat
4. Waterproof membrane
5. Sloped concrete deck
6. Structure
```

### Membrane Options
| Type | Traffic | Cost |
|------|---------|------|
| Fluid-applied (traffic) | Yes | $$$ |
| Modified bitumen | Limited | $$ |
| Single-ply + protection | With topping | $$$ |
| Spray polyurea | Yes | $$$ |

### Slope Requirements
| Surface | Minimum Slope |
|---------|---------------|
| Membrane | 2% (1/4" per foot) |
| Pavers on pedestals | Level (drain below) |
| Topping slab | 2% min |

### Drainage
- Drains at low points
- Area drains through pavers
- Overflow scuppers
- Inspection ports

---

## Green Roof Waterproofing

### Assembly
```
Top to bottom:
1. Plants
2. Growing medium (4"-12")
3. Filter fabric
4. Drainage layer
5. Root barrier
6. Waterproof membrane
7. Roof deck
```

### Membrane Requirements
- Root resistant or with root barrier
- Minimum 60 mil
- Fully adhered preferred
- Flood testing required

### Root Barriers
| Type | Description |
|------|-------------|
| Integral | Membrane with root resistance |
| Applied | Separate root barrier layer |
| Copper foil | Physical barrier |

---

## Interior Wet Areas

### Shower/Tub
| Layer | Material |
|-------|----------|
| Framing | Wood or steel studs |
| Backing | Cement board (not greenboard) |
| Membrane | Sheet or liquid applied |
| Mortar | Thin-set |
| Finish | Tile |

### Membrane Options
| Type | Application |
|------|-------------|
| Sheet (e.g., Kerdi) | Adhered to backer |
| Liquid (e.g., RedGard) | Rolled or brushed |
| Foam board | Pre-formed shower system |

### Shower Pan
- Pre-sloped mortar bed or pre-formed
- Drain with clamping ring
- Membrane turns up walls 6" min
- Dam at door threshold

---

## Swimming Pools

### Pool Waterproofing
| System | Description |
|--------|-------------|
| Integral concrete | Dense concrete, crystalline additive |
| Cementitious coating | Pool plaster |
| Vinyl liner | PVC sheet |
| Fiberglass shell | Factory made |

### Structural Requirements
- Reinforced concrete
- Water stop at construction joints
- Expansion joints at deck/coping
- Hydrostatic relief valves

---

## Roofing as Waterproofing

### When Roof = Waterproofing
- Vegetated roofs
- Occupied roofs/terraces
- Parking over occupied
- Mechanical platforms

### Testing
| Test | Description |
|------|-------------|
| Flood test | 2" water, 48-72 hours |
| Spray test | ASTM D5957 |
| ELD (Electric) | Detect breaches |
| Visual | During and after |

---

## Joints and Details

### Expansion Joints
| Location | Treatment |
|----------|-----------|
| Building expansion | Flexible membrane system |
| Plaza slab | Expansion joint cover |
| Wall-to-slab | Flexible detail |

### Waterstops
| Type | Use |
|------|-----|
| PVC (ribbed) | Construction joints, concrete |
| Metal | Heavy-duty, structural |
| Hydrophilic | Swells when wet, backup |
| Injection port | Post-construction repair |

### Penetrations
| Penetration | Treatment |
|-------------|-----------|
| Pipes | Pipe boot with clamp |
| Conduit | Sleeve and seal |
| Handrail | Base flashing |
| Drains | Clamping ring, membrane |

---

## Protection and Drainage

### Protection Board
| Material | Use |
|----------|-----|
| Extruded polystyrene | Insulation + protection |
| Protection mat | Impact, root |
| Hardboard | Mechanical protection |
| HDPE dimple | Drainage + protection |

### Drainage Board
| Type | Description |
|------|-------------|
| Dimple board | HDPE, drainage cavity |
| Geocomposite | Core + fabric |
| Gravel | Traditional, heavy |

### Filter Fabric
- Prevents soil migration into drainage
- Non-woven preferred
- Wrap drain pipe
- Cover drainage layer

---

## Quality Control

### Inspection Points
- [ ] Substrate preparation
- [ ] Primer application
- [ ] Membrane application
- [ ] Seam welding/adhesion
- [ ] Penetration treatment
- [ ] Protection installation
- [ ] Flood test/inspection

### Common Failures
| Issue | Cause | Prevention |
|-------|-------|------------|
| Blisters | Moisture in substrate | Dry substrate, primer |
| Fish mouths | Poor adhesion at laps | Proper technique |
| Punctures | Damage during backfill | Protection board |
| Cracks | Substrate movement | Flexible membrane |
| Leaks at penetrations | Poor detail | Proper terminations |

### Flood Testing
| Area | Duration | Water Depth |
|------|----------|-------------|
| Roofs | 24-48 hours | 2" |
| Planters | 24-48 hours | 2" |
| Pools | 48-72 hours | Full |
| Fountains | 48-72 hours | Full |

---

## Repair and Maintenance

### Common Repairs
| Issue | Repair Method |
|-------|---------------|
| Small puncture | Patch with same material |
| Lap failure | Cut, repair, overlay |
| Crack | Flexible sealant, overlay |
| General failure | Full replacement |

### Maintenance Schedule
| Task | Frequency |
|------|-----------|
| Visual inspection | Annually |
| Clear drains | Seasonally |
| Check flashings | Annually |
| Re-seal exposed | As needed |
| Professional inspection | 5 years |
