Problem Solving Forum
July 16 - July 20, 2018
We need to paint our publicly owned lighthouse. What should I include in the specifications for this bid regarding surface preparation, coating systems, and other considerations?
Selected Answers
From
Regis Doucette of Durable Solutions on
July 25, 2018:
Non-visible contaminants should be addressed throu ...read more
Non-visible contaminants should be addressed throughout as this structure is exposed to those soluble salts. After ion-specific testing, a liquid additive is added to wash water as the final step before a primer coat is applied.
From
Fred Salome of CTI Consultants Pty. Ltd. on
July 22, 2018:
Lighthouses are usually old, located in highly exp ...read more
Lighthouses are usually old, located in highly exposed environments and often have a mixture of materials of construction. Add to that a long and probably poorly documented maintenance painting history and a touch of lead or similar hazardous ingredients, and more than likely a remote location. A challenge for anyone. Get help.
From
rON Lewis of Corrosion Management Ltd on
July 20, 2018:
I fully concur with Eric Murrell's answer to this ...read more
I fully concur with Eric Murrell's answer to this question.
Ken Jacobi also has a very valid point here.My firm in Southeast Asia just completed the restoration of a public Light House that was well beyond re-painting. The product used was a paste primer over-wrapped with a composite material to cap beams and flat surfaces, relying completely on the bond strength between the substrate and the composite system.
SURFACE PREPARATION For the composite repair and reinforcement to perform, for either a seismic/structural strengthening application or a spall repair, the energy from the structure must be transferred from the substrate through the adhesive and into the wrap, This cannot occur unless there is intimate contact between the structure and the wrap. Because this is so important, the surface preparation step must be done with great care in order to ensure a strong bond. 1. Remove all loose and spalled material from the structure. 2. Deep clean the structure with either sand blasting or high-pressure water blast. 3. Inspect reinforcing steel and use methods to repair or treat the steel for corrosion degradation. 4. Restore the surface to its original condition by patching, gunnite, shot-crete or other suitable means. Avoid leaving depressions, as the composite will not adhere in depressed areas, thus requiring resin injection after the material is cured. Note that injection is very labor intensive. Surface deformities should be less than 12.7 mm in diameter and less than 6.35 mm in depth. The finished surface should be trowel-smooth. 5. After repairs, remove all dust and excess repair material. 6. Wash the surface with a low-pressure (2000 psi) water. 7. Allow the surface to dry prior to the installation of the adhesive tape wrap.
Not only does the lighthouse have a new highly resistant (Sun & Sea) surface but it is also now structurally re-established. At least the two we did in SEA (Southeast Asia) have been for the first 6 years of their warranted 15 year programed life extension.
From
Tom Tipps of Tom Tipps on
July 20, 2018:
In what state
is the lighthouse located? ...read more
In what state
is the lighthouse located?
From
Ken Jacobi of Bechtel on
July 18, 2018:
You use a coating consultant who can also evaluate ...read more
You use a coating consultant who can also evaluate the structural condition. Don’t just repaint over a structural deficient structure.
From
Trevor Neale of Blastco on
July 18, 2018:
Absolutely correct, Eric ! ...read more
Absolutely correct, Eric !
From
Eric Murrell of SME on
July 18, 2018:
If you cant answer these questions yourself, I rec ...read more
If you cant answer these questions yourself, I recommend you not try to go it alone. Hire a coatings consultant to develop your specification. A good consultant will be worth more than his/her fee.