How do I quote waterproofing with a tiling job?

Quote waterproofing as a separate line item, never bundled into your tiling rate. It carries its own licence in several states, it is governed by AS 3740:2021, and it is the single most common source of serious building defects in Australia. Getting the scope right protects your margin, your licence and your reputation.

Updated 23/09/2026

Why should waterproofing be a separate line item on a tiling quote?

Waterproofing and tiling are two different scopes of work, even when you do both on the same job. Separating them on your quote does three things.

• Protects your compliance position. Waterproofing is licensed separately in QLD, NSW and TAS. A bundled line item makes it harder to demonstrate you quoted, performed and documented the waterproofing as compliant work under AS 3740:2021.
• Makes variations transparent. If the customer adds a wet area or extends a shower niche, the waterproofing variation has its own rate. You are not renegotiating a lump sum.
• Reduces disputes. When a leak surfaces months later, your quote shows the customer exactly what waterproofing scope they approved, and your compliance photos prove it was executed to standard.

The trap is bundling waterproofing into a per-square-metre tiling rate. It hides a compliance-critical step, creates scope confusion and erodes your margin on the component that carries the highest defect risk in Australian residential construction.

What should the waterproofing section of your quote include?

A clear waterproofing scope on a tiling quote covers the following items. Each one protects you if a defect claim surfaces years after the job.

1. Substrate preparation. State the prep method (grinding, patching, priming) and note any existing membrane removal. Prep is where most failures start, and the customer needs to see it priced.
2. Membrane system. Name the product, the number of coats and the application method (brush, roller, spray). Specify the membrane type (liquid-applied, sheet) and reference AS/NZS 4858 for material compliance.
3. Coverage areas. List every surface being waterproofed: shower floor, shower walls to the required height, bath hob, floor waste surrounds, wet-area junctions. Spell out what is included and what is excluded.
4. Shower-wall height. Under AS 3740:2021, shower walls must be waterproofed to a minimum of 1,800 mm above finished floor level, or 50 mm above the shower rose, whichever is higher. State the height in the quote so there is no ambiguity.
5. Penetration and junction detailing. Pipe penetrations, floor-to-wall junctions and internal corners need specific treatment (bandage tape, pre-formed corners). These are where leaks occur and should be called out.
6. Flood test and inspection. Include a flood test (typically 24 hours (industry standard, directional) of ponded water on the shower base) and note that the membrane will be inspected and photographed before tiling proceeds. This is your evidence trail.
7. Cure time. State the cure window (commonly 24 to 72 hours depending on the membrane product and conditions, directional) so the customer understands why tiling does not start the same day.

How much does waterproofing cost on a tiling job?

Waterproofing typically costs $40 to $80 per square metre for residential wet areas before GST¹. Complex scopes (balconies, basements, large format areas) push rates toward $110 per square metre¹. The range depends on substrate condition, membrane type, number of penetrations and total area.

These are the waterproofing component only, on top of your tiling rate. Quoting them separately lets you price variations at the same per-square-metre rate without renegotiating the whole job.

Which states require a waterproofing licence?

Waterproofing is the most consistently licensed finishing trade in Australia. The common trap is assuming your tiling licence covers it.

"You must have a contractor licence to carry out, advertise or contract for building or trade work that is valued at more than $5,000 in labour and materials (including GST)." (NSW Fair Trading)

If you are a tiler who also waterproofs, check whether your existing licence class covers it. In QLD, the tiling and waterproofing trade contractor classes are separate. Advertising "licensed waterproofer" without holding the correct class is a false representation under ACL s29 and a state licensing offence.

How do I build a compliance evidence trail for waterproofing?

Waterproofing is the number one serious defect in NSW Class 2 apartment buildings, accounting for 42 per cent of serious defects in 2023². 85 to 97 per cent of multi-residential insurance claims involve water-related defects³. Those numbers mean a waterproofing defect claim is not a remote risk. It is the most likely serious claim a tiler will face.

Your evidence trail is your defence. Build it into every job as a standard process, not an afterthought.

• Photograph the substrate before prep. Timestamped, geotagged. This proves the starting condition and shows any pre-existing damage you are not responsible for.
• Photograph membrane application. Each coat, with product labels visible in at least one shot. This proves the right product was used at the right coverage.
• Document the flood test. Photo at fill, photo at 24 hours (industry standard, directional). Note the water level and confirm no drop. This is the single most important piece of evidence in a defect dispute.
• Record the sign-off. The builder, homeowner or certifier signs off on the membrane before you tile over it. Once tiles go down, the membrane is invisible, and your photos are the only proof it was done correctly.

Job management software like ServiceM8 or Tradify makes this a one-tap photo and checklist from site, timestamped and geotagged automatically. The compliance evidence stays with the job record, not in your camera roll.

What are the common mistakes tilers make when quoting waterproofing?

These are the errors that cost margin, create disputes or expose you to a licensing breach.

• Bundling waterproofing into the tiling rate. The customer does not see the cost, you cannot vary it cleanly, and your compliance documentation is weaker.
• Underquoting prep. Substrate preparation on a renovation is unpredictable. Old adhesive, uneven screeds and failed existing membranes all add time. Quote prep as a range or a provisional allowance, not a fixed price, on renovation work.
• Skipping the flood test. A flood test costs you one day of waiting. Skipping it saves a day but removes your single strongest piece of evidence in a defect dispute that could cost thousands.
• Assuming your tiling licence covers waterproofing. In QLD, it does not. In NSW, you need a separate waterproofing contractor licence above $5,000. Check before you quote.
• Not referencing AS 3740:2021 in the quote. Citing the standard signals competence to builders and certifiers, and it anchors your scope to a documented requirement rather than a verbal understanding.

How does waterproofing affect your tiling job timeline?

Waterproofing adds time to a tiling job, and your quote needs to account for it. A customer who expects tiles on the wall tomorrow will push back unless the quote explains why the membrane needs to cure first.

1. Day 1: substrate prep and priming. Grinding, patching, cleaning and applying primer. On a standard bathroom this is a half to full day depending on the existing condition.
2. Day 2: membrane application (coat 1). First coat of liquid-applied membrane to all wet-area surfaces. Bandage tape and pre-formed corners at junctions and penetrations.
3. Day 3: membrane application (coat 2) and cure start. Second coat applied perpendicular to the first. The cure clock starts after the final coat.
4. Day 4: flood test. Shower base ponded for a minimum of 24 hours (industry standard, directional). No tiling until the test passes and the membrane is signed off.
5. Day 5 onward: tiling. Membrane cured, flood test passed, sign-off recorded. Tiling can proceed.

That is a minimum of two days added to the tiling schedule for waterproofing on a standard bathroom. Build it into the quote timeline and note the cure requirement so the customer understands the sequencing. Rushing the cure to keep a schedule is how defect claims start. For more on tiling rates and job scoping, see our guide to quoting a tiling job in Australia.

What tools help you quote waterproofing faster and more accurately?

Speed and accuracy on waterproofing quotes come from measuring once, pricing from a catalogue, and sending the quote the same day.

• ServiceM8. Mobile-first, offline-capable, with digital compliance forms and checklists that are well suited to AS 3740 membrane and flood-test records. Xero and MYOB integration. From around $29 per month⁴.
• Tradify. Catalogue-based quoting with digital sign-off and a client portal. From around $35 per user per month⁵. Good for multi-staff operations where tiling and waterproofing crews need shared scheduling.
• Buildxact. Estimating and takeoff focused, with material takeoff from plans. From around $149 per month⁶. Best for tilers who regularly quote from architectural plans and need automated waste calculations.

All three integrate with Xero or MYOB for invoicing. The right choice depends on whether you are a sole trader doing residential bathrooms (ServiceM8), a crew doing mixed residential and commercial (Tradify), or a business that quotes regularly from plans (Buildxact). For a broader comparison, see our guide to job management software for tradies.

How do I protect my margin on the waterproofing component?

Waterproofing is a low-material, high-labour scope. The margin risk is in underquoting prep and in absorbing scope changes without a variation.

• Price prep as a range on renovations. "Substrate preparation: $X to $Y depending on existing condition, confirmed after first-day inspection." This avoids underquoting when old adhesive or a failed membrane adds hours.
• Use a per-square-metre rate for the membrane scope. It makes variations arithmetic, not negotiation.
• Charge for the flood test day. That day is lost tiling time. Include it as a line item or build it into your waterproofing rate, but do not absorb it.
• Log variations in writing before doing the work. An extended waterproofing scope (extra niche, relocated drain, additional wet area) gets a written note with the price adjustment, confirmed by the customer before you proceed. Quoting software makes this a one-tap variation from site.

If you want more on getting your hourly rate right and protecting margin across all your work, see our guide to setting your hourly rate.