Choose waterproofing by the conditions it must handle: where it will be used, what it will bond to, whether it stays exposed, and how joints and penetrations will be sealed. Then check the full system against the approved project specification and current manufacturer documents.
1. Start with the application
Roofs and exposed areas
First establish whether the waterproofing will remain exposed or sit beneath a protective layer. Ask about sunlight, access, roof drainage and detailing around pipes or equipment. Liquid-applied and sheet systems offer different detailing and installation approaches; compare the specified roof assembly rather than the main product alone. [1]
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Bathrooms, balconies and other tiled wet areas
The waterproofing layer must suit the substrate and the finishes placed over it. Cementitious waterproofing products include rigid and crack-bridging types, so they are not all equivalent. Check the approved treatment at corners, drains, pipe penetrations and changes of plane. [2]
Basements and below-ground structures
Below-ground selection begins with the project design, site conditions and construction sequence. Consider new-build versus remedial access, the side from which water is expected, and how walls, slabs and joints connect. Sika describes below-ground waterproofing as a system-selection and detailing task, with several membrane and concrete-based approaches available. [3]
2. Compare material types without oversimplifying
| Material type | Where it may be considered | What to verify |
|---|---|---|
| Sheet membranes | Specified roof or below-ground assemblies. | Substrate, fixing or bonding method, seams, penetrations and protection. |
| Liquid-applied systems | Specified roofs, terraces or areas with complex details. | Primer, reinforcement, applied thickness, exposure and topcoat requirements. |
| Cementitious coatings | Specified concrete or masonry applications, including some under-tile and water-retaining systems. | Rigid or flexible grade, movement requirements, substrate and permitted water contact. |
| Joint systems | Construction or movement joints requiring a separate watertight detail. | Joint design, movement, sealant or waterstop specification and component compatibility. |
Manufacturers offer several technologies within each group. A material-family name does not establish that an individual product is suitable. [1] [2] [3]
3. Check the complete waterproofing system
The membrane or coating is only part of the material schedule. Ask which preparation materials, primers, reinforcement, joint treatments and protective layers the selected system requires. Manufacturer guidance treats the design, detailing and installation as connected parts of waterproofing performance. [4]
A useful buying question is: “What else must be included for this specified system to be complete?”
For procurement, turn the answer into an itemised schedule. Record the exact product references and document revisions rather than a general label such as “waterproof coating”. Keep any proposed alternative separate so the project team can assess it before an order is confirmed.
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4. Avoid these common buying mistakes
- Choosing only by price per pack. Ask for quantities and costs against the same specified area and system build-up.
- Leaving details out of the enquiry. Include corners, penetrations, terminations and joints in the material schedule where specified.
- Assuming products in one family are interchangeable. Check the exact grade, application and required documentation.
- Ordering before confirming the specification. Separate approved products from alternatives still awaiting review.
- Assuming catalogue stock is confirmed. Request current availability, pack sizes and lead time for the quantities needed.
5. Prepare a clear material enquiry
Use the following checklist when requesting a quotation from Buildcare:
- Project name, delivery location and required date.
- Application: roof, basement, wet area or another specified use.
- Substrate, existing finishes and whether the work is new or remedial.
- Area, drawings and relevant joint or penetration details.
- Approved manufacturer system and exact product references.
- Specified thicknesses, pack sizes and requested quantities.
- Supporting components and required technical documents.
If you need help building the enquiry, start with the waterproofing materials supplier page or browse the waterproofing catalogue.
Common questions
Is there one waterproofing material that works everywhere?
No. Start with the location, substrate, exposure and complete construction detail. A product listed for one application should not be assumed suitable for another without checking its current data sheet and specified system.
Are tile grout and sealant the same as a waterproofing membrane?
They have different roles in an assembly. A wet-area specification may include an under-tile membrane plus compatible joint treatments and finishes. Check the complete detail rather than treating a surface finish as a replacement for the specified membrane.
Can I choose by price per bucket or roll?
Compare the cost of the complete specified system over the required area. Include coverage at the stated thickness, preparation, primers, reinforcement, joint components, protection and application requirements.
How can I get a more accurate materials quotation?
Send the approved specification, application, substrate, area, quantities, project location and required date. Ask for the full material schedule and current technical documents. If you have not selected a system, say so in the enquiry.
Have a specification or BOQ?
Send Buildcare your application, material list and project location for product availability, documentation and a quotation.
Call 02 448 1915 · info@buildcareint.com
Manufacturer references & scope
This guide explains selection questions. Final system selection, quantities and installation requirements should follow the approved project design and current regional manufacturer documentation.
- Fosroc ANZ: Waterproofing — where do I start? General technology and application background; regional product availability and approvals differ.
- Sika GCC: Waterproofing mortar Cementitious waterproofing approaches and application categories.
- Sika: Below-grade waterproofing System selection for basements and underground structures.
- Sika GCC: Waterproofing Whole-system concepts, specification and detailing.
References checked on 20 October 2026.