Envelope & Interiors
Waterproofing Estimating Services in New Zealand
Membrane and tanking quantities for wet areas, decks, basements and roofs, with upstands, outlets and junction details counted.
Waterproofing failures are expensive, and so is waterproofing done properly. The cost is less about flat area and more about the details: upstands, corners, outlets, penetrations, thresholds and junctions with other materials. That is where membranes fail, and where installers spend their time.
We measure waterproofing by location and system: wet-area membranes in showers and bathrooms, deck and balcony membranes, roof membranes, basement and retaining wall tanking, and planter boxes. Flat areas, upstands and turn-downs are measured separately, and every outlet, penetration and junction detail is counted.
This gives the waterproofing applicator a scope they can price accurately, and gives the builder a clear picture of what is included.
Scope
What we measure in a waterproofing takeoff
| Item | Unit | What it covers |
|---|---|---|
| Wet-area membranes | m² | Floors and walls in showers and wet areas. |
| Deck and balcony membranes | m² | Over habitable spaces and exposed decks. |
| Roof membranes | m² | Flat roofs and gutters. |
| Basement tanking | m² | Walls and slabs below ground. |
| Upstands and turn-downs | lm | At walls, thresholds and edges. |
| Outlets and penetrations | no. | Drains, overflows and pipe penetrations. |
| Substrates | m² | Plywood, fibre cement or screeds under membranes. |
| Drainage layers | m² | Protection boards and drainage behind retaining walls. |
Deliverables
What you receive
Waterproofing estimates count each detail type separately, so applicators can price details at their own rate rather than averaging into the area rate.
| Itemised quantity sheet | Excel + PDF |
| Marked-up plans | Colour-coded PDF |
| Material and labour schedule | Excel |
| Assumptions and exclusions list |
Who it is for
Built for the people who price the work
- Builders
- Get a waterproofing scope that matches the details on the drawings.
- Subcontractors
- Applicators can quote areas and details separately.
- Developers
- Understand the cost of balconies over living spaces in apartments.
- Architects
- See the cost effect of level-entry showers and flush thresholds.
Process
How a waterproofing estimate runs
STEP 01
Upload plans
Upload plans, sections, waterproofing details and the specification.
STEP 02
Scope confirmation
We confirm membrane systems, substrates and who is responsible for each junction.
STEP 03
Takeoff and review
Areas, upstands and details are measured and checked against floor and deck areas.
STEP 04
Delivery
You receive the waterproofing schedule, detail counts, PDF and marked-up plans.
New Zealand context
Standards and practice
Internal wet areas must meet Building Code clause E3 (Internal moisture). Membranes in New Zealand are commonly used with a BRANZ Appraisal or CodeMark certificate, and installation by an approved applicator may be required by the manufacturer. We measure the specified system and note any approved applicator requirements.
External decks and roofs fall under clause E2 (External moisture). Membrane decks over living spaces carry higher risk, so details such as falls, upstand heights and outlet sizes are important, and we measure them as drawn.
We measure and price to the drawings. Design compliance and building consent remain with your designer and building consent authority.
Cost drivers
What drives the cost of waterproofing work
01
Number of details
Outlets, penetrations, thresholds and corners take far more time than flat areas. A small deck with many details can cost more than a large plain one.
02
System type
Liquid-applied, sheet and torch-on membranes have different material and labour costs. The specified system controls the price.
03
Substrate preparation
Membranes need sound, clean and correctly falling substrates. Creating falls with screeds adds material and time.
04
Approved applicator
Some systems must be installed by approved applicators, which may limit the pool of contractors and affect price.
Where waterproofing estimates go wrong
Waterproofing is often priced on flat area only. Upstands, turn-downs, outlets and penetrations are where the time goes, and they can double the effective cost of a small deck or shower.
Substrate is the other common gap. Membranes need the right substrate with the right falls, and creating falls with screed or tapered sheets is a separate item that is easy to miss.
Sequencing is the last common problem. Membranes are often damaged by following trades, or installed before penetrations are finalised, which means patching and retesting. We note where protection boards or flood testing are specified, because both take time and materials that are easy to leave out of a price. Flood testing a shower or deck before tiling or decking, and protecting the membrane afterwards, are good practice and often specified. Warranty registration and producer statements may also be required by the membrane supplier.
FAQ
Waterproofing Estimating questions
Do you measure upstands separately?
Yes. Upstands and turn-downs are measured in lineal metres separately from flat areas.
Do you count outlets and penetrations?
Yes. Every outlet, overflow and penetration is counted.
Can you estimate basement tanking?
Yes, including walls, slabs, protection boards and drainage layers.
Do you include substrates?
Yes. Substrates under membranes are measured where they are part of the scope.
Can you estimate tiled showers?
Waterproofing is measured here; tiling is under finishes or flooring. We can combine them if you prefer.
Related services
- Roofing Estimating
True roof areas calculated by pitch, with sheet lengths, flashings, gutters, downpipes and underlay measured for ordering.
- Flooring Estimating
Floor finish quantities by room and material, with roll and plank layouts, trims, underlay and subfloor preparation.
- Finishes Estimating
The fit-out that clients notice: tiling, splashbacks, cabinetry, fixtures, accessories and fit-off, measured from the finishes schedule.
- Excavation Estimating
Detailed excavation quantities for footings, basements, trenches and pits, with backfill, disposal and support measured separately.
Get a quote
Send your plans for a waterproofing estimate
Upload your drawings and we will reply with a fixed fee and turnaround before any work starts. No obligation.
- — PDF, DWG and ZIP accepted
- — Fees in NZD, excluding GST
- — Prefer email? Use the link in the footer