Graco Inc.

Polyurea application on damaged fiber cement roof



In this case, we describe the retrieval of a fiber cement roof by applying a polyurea coating before the installation of a photovoltaic panel system.  The fiber cement roof showed several damages and general lesions due to exposure to the elements for over 10 years with as consequence: cracks and water leakages inside the building.


The consolidation of the 800m2 roof was carried out by first cleaning the external surface with high pressure water, followed by the quick application of a 2mm layer of MPM Starflex HR-E polyurea coating. Where the roof was particularly damaged, a thicker layer of polyurea was applied.

Thanks to this application, the replacement of the damaged elements was avoided. A replacement of the damaged items would have required an expensive procedure and an alteration of the use of the building during the application process.

Another advantage obtained by applying a polyurethane reflective white paint was to achieve a considerable reduction (more than 5 °C) of the heat conduction.

From the pictures provided, it is possible to evaluate all the steps during the application process, up to the final installation of the photovoltaic panels over the regenerated external surface.


The application of pure polyurea over a damaged fiber cement roof solved not only the problem related to the disposal of the old plates, but also provided a perfect impermeability of the external surface as well as the reduction of heat conduction caused by the application of the white polyurethane paint.


Bossi Renato, Italy

Industry Market Sector
The application of thermoplastic materials, lastomers and polyureas

Material Specifications
MPM, High performance fluid polyuria Starflex HR-E

Hardening at 22°C within 5 minutes dry to the touch,
Adhesion to concrete >3.0 MPa,
Degree of water vapor transmission µ >1500,
Falling weight test at 2m height = passed
Ususry resistance < 40 mg
Resistance to thermal shock > 2.2 MPa
Lenthening to breakage point > 600%
Traction resistance >14 MPa
Shore A hardness = 70 – 80
Flashpoint of components > 95°C

Graco Equipment
Reactor E-XP2I ref. AP9191
Fusion AP gun, mix chamber AR2929
T2 feeding system, 93m heated hoses

The Reactor E-XP2I was configured for spraying polyurea in standard conditions.
Temp:  60/65°C
Pressure: 180 bar
Ratio 1:1

Graco Distributor Details
Stefano Stefanini, Italy


Bossi Renato