A CFRP strengthening ITP is the document that proves the installation was inspected, tested and recorded at the right stages. While carbon fibre plates and wrap are often judged visually after installation, the real value of an inspection and test plan is that it captures the evidence before, during and after the bonded strengthening system is installed.
This matters because CFRP strengthening depends on a chain of controls. The design may be correct, the product may be suitable and the installer may be competent, but the project still needs proof that the concrete was prepared, tested, bonded, cured, inspected and handed over correctly. Without an ITP, that evidence can become fragmented across photographs, emails, site notes and memory.
This article forms part of London Construction Magazine’s practical guide to carbon fibre strengthening in existing concrete structures, where CFRP is treated as a structural evidence process, not just a material installation.
The ITP Should Follow the Strengthening Sequence
A good CFRP strengthening ITP should follow the actual installation sequence. It should not be a generic form with vague inspection boxes. The document should show what needs to be checked before surface preparation, after preparation, before bonding, during installation, after curing and at final handover.
The sequence will depend on whether the work involves CFRP plates, carbon fibre wrap, slab soffits, beam strengthening, column confinement, slab openings or local repair. A plate installation may need hold points for setting-out, adhesive mixing, glue line and tap testing. A wrap installation may need checks for corner radius, fibre orientation, resin saturation, overlaps and air release.
The ITP should therefore mirror the method statement and the engineer’s design. If the design requires pull-off testing, surface profile confirmation, environmental readings or engineer inspection before installation, those items should appear as inspection points in the ITP rather than being left as informal site practice.
Hold Points Protect the Bond Chain
The most important ITP items are usually the hold points. These are the stages where the works should not continue until the required inspection or test has been completed. In CFRP strengthening, the most important hold points often sit around substrate acceptance, pull-off testing, environmental suitability and final installation inspection.
For example, the site team should not normally proceed to bonding if the concrete surface still contains laitance, paint, plaster, dust, weak repair mortar or loose concrete. Mechanical grinding, grit-blasting, vacuum cleaning and local repair may all need to be inspected before adhesive is applied. Where a specified profile is required, such as an ICRI CSP 3 to CSP 5 type surface profile, the ITP should record how that requirement was checked.
This is where the ITP becomes a project risk-control tool. It prevents the work moving too quickly from preparation to installation without proof that the concrete substrate is suitable. That is essential because bonded CFRP systems are only as reliable as the prepared surface they rely on.
| ITP Stage | Evidence That Should Be Recorded |
|---|---|
| Pre-start review | Latest drawings, RAMS, product data, COSHH, access arrangement, design scope and hold points confirmed. |
| Substrate preparation | Photographs showing laitance removal, coating removal, dust control, surface profile and sound concrete exposure. |
| Pull-off testing | Dolly locations, curing period, test values, failure mode, acceptance criteria and engineer review where required. |
| Installation | Resin batch numbers, mixing records, working time, plate or wrap location, fibre direction, glue line or saturation checks. |
| Final handover | Final photographs, curing records, defect checks, sign-off, no-drill restrictions and maintenance information. |
Pull-Off Results Must Be More Than a Number
Pull-off testing is one of the most important records in a CFRP ITP because it confirms whether the prepared concrete surface can provide the tensile bond strength required for the bonded system. A typical minimum value used on many CFRP projects is 1.5 N/mm², but the ITP should always refer back to the project specification, engineer’s design and selected system data.
The test value should not be recorded alone. The ITP should also capture test location, dolly size, test date, curing period, equipment reference, failure load, calculated bond strength and failure mode. Concrete substrate failure, adhesive failure and interface failure each tell a different story about the bond chain.
This is why London Construction Magazine treats pull-off testing before carbon fibre strengthening as a live quality control point. The test is not just there to satisfy a form. It helps decide whether the prepared surface is suitable before the project commits to installation.
Environmental Records Should Sit Inside the ITP
CFRP strengthening involves epoxy adhesives and resin systems, so environmental conditions must be recorded. The ITP should include substrate temperature, ambient temperature, relative humidity and dew point before installation and, where required, during curing.
For epoxy resin works, the substrate temperature should normally be at least 3°C above dew point to reduce condensation risk. The installed system must also remain within the curing limits set by the selected resin product. If the concrete is too cold, too damp or too close to dew point, the bond may be affected even if the surface looks dry.
The ITP should also record product batch numbers, expiry dates, mixing ratios and working times. This is especially important where plates or wrap are installed in stages, where multiple resin batches are used, or where the programme puts pressure on operatives to continue working close to the end of pot life.
These controls should align with the project RAMS. London Construction Magazine’s guide to CFRP strengthening RAMS before site works explains why resin handling, COSHH, access, dust control and environmental conditions need to be planned before the ITP can be properly followed on site.
Installation Checks Must Match Plates or Wrap
A CFRP plate ITP should not be identical to a carbon fibre wrap ITP. Plates require checks for set-out, cutting, cleaning of bonding faces, adhesive application, glue line, plate alignment, termination zones, excess adhesive removal and void checks where specified. The final record should show that the plate was installed in the correct position and direction, not simply that a strip was bonded to concrete.
A carbon fibre wrap ITP should include checks for corner radius, surface levelling, primer or putty where required, fibre orientation, resin saturation, overlap lengths, air release, layer sequencing and recoat timing. Dry fabric, trapped air, poor overlaps or incorrect fibre direction can weaken confidence in the finished system.
The ITP should also record final restrictions. Follow-on trades should know where CFRP zones are located and that drilling, cutting, chasing or fixing through the strengthened area should not proceed unless reviewed by the responsible engineer. This is especially important once ceilings, finishes, fire stopping or services hide the strengthened element.
Where the ITP Becomes Handover Evidence
The strongest CFRP ITPs are written with handover in mind. The final record should allow a client, engineer, contractor, building owner or future maintenance team to understand what was installed, where it was installed, under what conditions and with what proof.
This is particularly important where the strengthened area will be covered by finishes or where future construction work may take place nearby. Photographs should show preparation, test locations, plate or wrap installation, completed areas and any no-drill zones. Records should include drawings, marked-up locations, test results, batch information, environmental logs, defect notes and sign-off sheets.
The ITP also connects back to design information. London Construction Magazine’s article on CFRP strengthening design information explains why drawings, concrete assumptions, reinforcement checks and substrate evidence need to be understood before CFRP is selected. The ITP is the document that helps prove those assumptions were checked during delivery.
ITP Evidence Summary
A CFRP strengthening ITP should capture the evidence that proves the installation followed the design, specification and method statement. It should include hold points for substrate preparation, pull-off testing, environmental checks, resin controls, plate or wrap installation, curing, defect review and final handover. The finished carbon fibre system may be thin and visually simple, but the ITP is what gives the project a reliable record of how that system was delivered.
CFRP ITP Questions Before Handover
What is a CFRP strengthening ITP?
A CFRP strengthening ITP is an inspection and test plan used to record preparation, testing, installation, curing, inspection and handover evidence for carbon fibre strengthening works.
What hold points should a CFRP ITP include?
Typical hold points include substrate preparation acceptance, pull-off testing, environmental checks, resin batch verification, installation inspection, curing confirmation and final sign-off.
Should resin batch numbers be recorded in the ITP?
Yes. Resin batch numbers, expiry dates, mixing records and working times should be recorded so the project can prove which materials were used and under what conditions.
Why does the ITP matter after CFRP is covered by finishes?
Once CFRP is hidden by ceilings, finishes or services, the ITP may become the main evidence showing where the strengthening was installed and what restrictions apply to future works.
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Expert Verification & Authorship: Mihai Chelmus
Founder, London Construction Magazine | Construction Testing & Investigation Specialist |
