Agree the prepared surface with the next trade
Photographs include sound coating, failing edges and the worst scale rather than only the damaged patch. The coating or repair contractor defines the surface it needs. A representative trial then shows whether the proposed water jetting method removes the unwanted material without extending into areas meant to remain. Surface preparation by water jetting can then be judged against the next trade’s stated requirement.
What the coating inspector needs to see
- Material beneath the coating or scale.
- Photographs of sound and badly affected areas.
- Material to remove and any coating allowed to remain.
- Access limits and the collection route for water and debris.
Trial area and agreed surface finish
Photographs should show sound coating as well as the worst affected areas. The coating type, substrate and finish required by the next trade then define a representative trial and the containment needed around it. Joints and edges are marked where the required finish changes. The inspector reviews the exposed trial beside the existing finish before work moves across the rest of the marked surface.
Once the trial is accepted, the marked sections are prepared while runoff and coating fragments stay on the collection route. The next trade compares the exposed surface with its stated repair or coating requirement.
If the deposit is particularly hard, our notes on coating and scale removal explain the questions worth answering first. For equipment access and isolation, see preparing equipment for jetting, or contact us to discuss the actual surface.
The surface beneath the coating or scale sets the practical limit. Steel, concrete and lined equipment can react differently to the same water jet. The review uses the known substrate condition, areas that must remain and the next coating or repair step before proposing a trial.
A representative test area shows whether the unwanted layer releases cleanly and what texture or defects remain underneath. It also gives the coating inspector or repair contractor a real surface to assess. If the result is unsuitable, the wider area should not be treated on assumption.
Runoff, removed coating and the next trade
Loose coating, rust, scale and contaminated water need to be caught close to the work. Sheeting, local collection and temporary storage depend on the surface position and the site’s drains. The waste route should be agreed before preparation begins, especially where the existing coating may contain regulated material.
Tell us how the prepared surface will be inspected and how soon the next treatment follows. Weather exposure, flash rust, remaining sound coating and inaccessible edges may affect the next contractor’s work. For harder build-up, see coating and scale removal.
Include the site location, approximate area, substrate, existing coating and photographs taken from both close range and further back. State whether the next step is inspection, repair or recoating and who will approve the prepared finish. Access height, enclosure and available drainage are also important. These details allow the provider to price the real preparation task rather than assume that every square metre can be treated in the same way.
Runoff and coating debris need an agreed collection route. The provider designs containment around the marked work face and the disposal arrangements available at the site.
If another contractor will coat the surface, provide its required condition before work starts. The inspection can then be aligned with the next stage.
The coating contractor’s specification should state the surface condition it needs before its own preparation, inspection or coating stage begins.