How Australian Tilers Quote Waterproofing and Wet Area Compliance

Waterproofing is where Australian tilers carry the most risk.

Get it wrong, and you're liable for water damage that can cost tens of thousands to fix.

Get it right, and waterproofing becomes a profitable, protected part of every wet area quote.

Understanding AS 3740 Requirements

What Must Be Waterproofed

Mandatory Waterproofing (AS 3740)

• Shower floors and walls (to 1800mm or ceiling if lower)
• Shower hobs
• Bath surrounds (to 1800mm above bath rim)
• Floor waste surrounds
• Junctions between wet area floors and walls

Recommended Waterproofing

• Entire bathroom floor
• Behind vanities
• Laundry floors
• Toilet floors (if tiled)

Waterproofing Classes

Class 1 — Residential

• Single membrane application
• Standard residential bathrooms
• Most common for tilers

Class 2 — Commercial Light

• Enhanced membrane system
• Higher traffic areas
• Some residential applications

Class 3 — Commercial Heavy

• Specialist application
• Pools, commercial kitchens
• Usually specialist waterproofers

Quoting Waterproofing Work

Labour Components

Surface Preparation

• Clean and prepare substrate: $15-25/m²
• Prime substrate: $8-12/m²
• Install bond breaker at junctions: $5-10/linear metre
• Install internal corners: $10-15/linear metre
• Install external corners: $10-15/linear metre

Membrane Application

• First coat application: $20-30/m²
• Second coat application: $15-25/m²
• Hob waterproofing: $50-80/linear metre
• Floor waste integration: $50-100 each

Drying Time

• Factor in 24-48 hours between coats
• Schedule accordingly

Material Components

Primers

• Acrylic primer: $15-25/litre (covers 8-12m²/L)
• Epoxy primer (for difficult substrates): $40-60/litre

Membranes

• Acrylic membrane: $80-120/15L (covers 1m²/L per coat)
• Polyurethane membrane: $150-250/15L
• Sheet membrane: $30-50/m²

Accessories

• Internal corners (preformed): $8-15 each
• External corners (preformed): $8-15 each
• Bond breaker tape: $20-40/roll
• Reinforcing fabric: $3-5/linear metre

Waterproofing Quote Example

Standard Bathroom (3m × 2m)

Preparation

• Surface preparation (6m²): $120
• Priming (6m²): $60
• Internal corners (8): $100
• Bond breaker (10 linear m): $60
• **Prep subtotal: $340**

Membrane Application

• Shower area floor (2m²) × 2 coats: $100
• Shower walls to 1800mm (5.4m²) × 2 coats: $240
• Hob (1.8 linear m): $120
• Floor waste: $80
• **Application subtotal: $540**

Materials

• Primer (2L): $40
• Membrane (10L): $80
• Corners and accessories: $60
• **Materials subtotal: $180**

Waterproofing Total: $1,060

Certification and Documentation

Waterproofing Certificate

Every waterproofing job requires:

• Waterproofer's licence number
• Membrane manufacturer and product
• Application dates
• Cure times observed
• Flood test results (if performed)
• Photos of completed membrane

Quote Inclusion

"Waterproofing Certificate: Included"

"Certificate will be provided upon completion of waterproofing and before tiling commences."

"Certificate is required for building sign-off and warranty claims."

Warranty Considerations

• Membrane manufacturer warranty: Usually 10-25 years
• Workmanship warranty: Your responsibility
• Document everything with photos

Common Waterproofing Mistakes That Cost Money

1. Insufficient Membrane Thickness

• Minimum 1.5mm total thickness
• Two coats minimum
• Check wet film thickness during application

2. Inadequate Drying Time

• 24 hours minimum between coats
• 72 hours before tiling
• Longer in cold or humid conditions

3. Missing Corner Treatments

• Every internal corner needs reinforcement
• Every external corner needs protection
• Junctions are failure points

4. Poor Substrate Preparation

• Dust and debris cause adhesion failure
• Curing compounds must be removed
• Moisture testing on concrete

5. Incorrect Fall to Waste

• Minimum 1:80 fall required
• Check before waterproofing
• Not your job to fix, but your job to identify

Pricing Waterproofing Separately

Always quote waterproofing as a separate line item:

Benefits

• Customers see the value
• Protects your margin
• Clear scope for warranty
• Easier to manage variations

Quote Presentation

**Tiling Works**

- Floor tiling (12m²): $XXX

- Wall tiling (24m²): $XXX

- **Tiling subtotal: $XXX**

>

**Waterproofing Works**

- Shower waterproofing complete: $1,060

- Waterproofing certificate: Included

- **Waterproofing subtotal: $1,060**

>

**Total: $XXX**

Using QuoteOS for Wet Area Quotes

1. **Enter wet area dimensions** — Shower, bath, floor
2. **AI calculates waterproofing** — Based on AS 3740
3. **Add tiling quantities** — With wastage
4. **Generate compliant quote** — With certification note

Try QuoteOS free → [Tiler Quoting Software](/trades/tilers)