ITP generator — waterproofing

The scope where an acceptance criterion falls due weeks before the work does — and where most ITPs discover that too late.

Waterproofing carries the single most instructive criterion in the corpus, and it is not about waterproofing at all. Where a curing liquid, compound or membrane is used on a surface that will later receive a waterproofing system, it has to be completely removable, with records kept of the compounds used and the areas of subsequent removal. That makes the concrete team’s choice of curing method a waterproofing acceptance criterion — falling due weeks earlier, on a different ITP, run by different people.

The rest of the scope is a weather and workmanship discipline: spread rates measured rather than judged, weld widths measured on every weld, and application windows governed by temperature, rain forecast and wind speed with the instrument named. Which is exactly why “as per manufacturer’s instruction” is defensible here only when the line also names the parameter, the frequency and the instrument.

It is free and there is no sign-up. Type the scope, read the whole plan on screen. Where the tool has not been given your specification, project-specific criteria come back marked TBC — EVIDENCE REQUIRED with the document that would close them named. That is the correct answer, not a limitation politely worded — an ITP that quietly fills a tolerance with a typical value is worse than one that leaves the box open, because somebody signs the first one.

What controls waterproofing

These are the documents an acceptance criterion on this scope has to agree with. A criterion that restates the activity and attaches a reference is doing half the job.

• BS 8102 — Protection of below-ground structures against water ingress — grades and types.
• BS 8000 series — Workmanship on building sites.
• MCHW Specification for Highway Works, Series 2000 — Waterproofing for concrete structures on highway schemes. OGL. Bridge-deck waterproofing carries its own regime and its own hold points — do not merge it into a below-ground plan.
• The system manufacturer’s specification and datasheets — Spread rates, weld parameters, substrate and weather limits. Legitimate as a criterion source only when the ITP names the parameter, the frequency and the measuring instrument alongside it.

The inspection sequence, and where the gates fall

Hold points belong where the evidence stops being recoverable, and the test is always the same question: what becomes invisible next? On this scope that puts 5 of the 11 steps below at a hold point — the rest are witness points, surveillance, review or recorded inspection depending on your contract and on who is watching.

1. Material approvals — primer, bitumen or membrane to the relevant grades
2. [H] Curing method on the substrate confirmed compatible and removable, with records of compounds used and areas removed — Falls due on the concrete pour, weeks earlier. This row exists to make somebody check it then.
3. [H] Cover-meter survey of the substrate complete and cover depths correct — Once the system is on, the cover survey is no longer possible.
4. Substrate preparation and cleanliness; moisture content within limits
5. Concrete curing period verified against the pour ticket date and time
6. Weather conditions checked — air temperature by thermometer, wind by anemometer, rain forecast
7. [H] First coat applied at the specified rate of spread to the specified extent
8. First coat allowed to dry; second coat applied
9. [H] Sheet membranes — substrate cleanliness immediately before application; every weld inspected and minimum weld width measured
10. Protection layer — substrate cleanliness confirmed before the geotextile goes down
11. [H] Post-application inspection and acceptance before backfill

One rule that catches people and is not negotiable: hold points cascade upward. Where the client, the designer or a third party has identified an intervention as a hold point, it is a hold point in your column too. You cannot accept theirs and keep yours as a witness.

Acceptance criteria that survive a review

The acceptance-criteria column header in one real template is the whole test: what answer should we get if it is right? If the entry does not let a third party, months later, decide pass or fail from the record alone, it is not an acceptance criterion. These are from issued ITPs on this scope — not composed as illustrations:

• Bitumen hot applied at a rate of spread of 0.6 litre/m² per coat; first coat allowed to dry before the second; coating to extend from the base to 150 mm below finished ground level over the whole structure.
• 7-day concrete curing period verified against the pour ticket date and time before application; minimum air temperature 5 °C; no application if rain is expected within 4 hours; applied uniformly at 4.9 m²/L with no puddling or pooling.
• Minimum sheet-membrane weld 50 mm, checked with a measuring tape; every weld checked with a flat-edged tester.
• Where a curing liquid, compound or membrane is used on surfaces that will receive a waterproofing system, it shall be completely removable, and records kept of all compounds used and the areas of subsequent removal.
• Cover-meter survey of the substrate complete and cover depths correct before the system is applied.

Against which, the ones that get marked every time: as per design · as specified in the material approval form · as per manufacturer’s instruction · document accepted · within accepted tolerances · acceptable to use · visual inspection · see notes. They fail for one reason: they defer the criterion to a document the inspector does not have on the deck, and they give the person signing nothing to be wrong about.

What comes back TBC on this scope, and where it comes from

The generator does not have your specification, so it will not invent these. It marks them and names the document that would close them:

• The system, its grade under BS 8102, and the manufacturer’s reference
• Spread rates per coat, and the extent of coverage above and below ground level
• Weld width and the test method for the membrane specified
• The weather envelope — temperature, wind and rain limits
• Who witnesses the pre-backfill acceptance, and how much notice they need

Other scopes

• ITP generator — in-situ reinforced concrete
• ITP generator — earthworks and fill
• ITP generator — drainage
• ITP generator — formwork and falsework
• ITP generator — precast erection

Why the generated draft is a draft, and stays one

Starting permanent works without an accepted ITP is a critical non-conformance in its own right, and proceeding through a hold point gets an NCR raised against you. Before this output is issued it needs the project references and drawing revisions, the criteria above completed from your specification, the responsible parties set against your own contract, the check-sheet numbering aligned — inspection item 4.12 on the ITP has to be item 4.12 on the check-sheet — and a named author, reviewer and approver.

So it says DRAFT — FOR COMPETENT REVIEW on its own title, and should keep saying it until a competent person has been through it against the specification.