Fiberglass Home Siding Material
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Ultrex Siding System: Composite Fiberglass Siding

Care & Maintenance


APEX Siding System products are high-performing, durable and low-maintenance. The APEX advantage comes from the Ultrex® material - a patented pultruded fiberglass that incorporates an integrated acrylic finish. Please take a few minutes to read the following information on general cleaning and repair to help keep your APEX products looking and performing their best. For questions not addressed in the below information, please call 888-307-3148.

Cleaning APEX Siding System

Periodic cleaning is necessary to remove dirt, mildew and other substances that can build up on your home's exterior. Surface dirt can be removed by washing with a mild detergent and rinsing with clear water. Please see below for other recommended cleaners. Use a non-abrasive brush, such as a long-handled car washing brush, to remove any stubborn dirt and grime. Scrubbing with abrasives or applying extreme pressure can damage the finish.

APEX products are very durable, but are susceptible to damage if improper chemicals or solvents are used. For best results when removing dirt or debris wash siding with water and/or approved cleaners. Before using more aggressive cleaners test the solution on an inconspicuous area before washing. A thorough clear water rinse should follow.

If you are cleaning only windows and doors, ensure that any window and door cleaners are thoroughly rinsed off of the siding immediately after cleaning.

Recommended cleaners

The following household cleaners are recommended to use with non-abrasive applicators:

  • Fantastic® cleaning detergent
  • Lysol®
  • Murphy's Oil Soap®
  • Ivory® dish soap
  • Spic and Span®
  • Household strength Tide® liquid detergent
  • Household strength Windex®

Follow each products specific use instructions. Apply with non-abrasive applicators or spray, and rinse thoroughly with clear water.

Not recommended

APEX products can be damaged with solvents, paint thinners, muriatic acid and other harsh cleaners that contain more than 10% isopropyl alcohol or ethanol. Use of these chemicals may damage your siding and trim and void the warranty.

Maintain the ventilation plane

APEX has a built-in water management system that allows water to drain and air to circulate. To maintain this ventilation plane, ensure that the bottom edge of the lowest siding lap is not covered with soil or other landscaping.

Painting APEX Siding System

APEX products are designed for low maintenance and do not require painting or caulking. If it becomes necessary to paint APEX products, an exterior-grade acrylic finish is recommended. Primer is not required, but the surface should be cleaned thoroughly. If the use of caulk is desired, choose one that is paintable. Please note that application of paint or any other finish over the factory finish will void the limited warranty with regard to the finish.

Repairing and Refinishing Ultrex

Minor damage to the APEX siding system can be repaired with common materials from your local hardware store. Ultrex has a fiberglass substrate similar to many automotive and marine products and has an acrylic finish that can be repaired with an exterior grade acrylic latex paint recommended by your APEX dealer.

You will need:
  • Utility knife
  • Epoxy putty for small repairs or fiberglass repair kits for larger repairs
  • Putty knife
  • 120-150 grit sandpaper
  • 320-400 grit sandpaper
  • Exterior grade primer
  • Exterior-grade acrylic latex paint (consult your APEX dealer)
  • Foam paint brush
  • Masking tape

1. Using the utility knife, remove any jagged edges or loose fibers.

2. Follow the manufacturer's recommendation for mixing/blending epoxy. Using a putty knife, fill the damaged area thoroughly with epoxy and remove excess. If using a fiberglass repair kit, follow manufacturer's instructions for application.

3. Once the repaired area has set and cured, sand the repaired area with 120-150 grit sandpaper until it is flush with the surrounding area. Finish by polishing with 320-400 grit sandpaper.

4. To ensure a properly blended finish with the repaired section, lightly sand surrounding area with 320-400 grit sandpaper to remove factory finish. Coat the repaired section and surrounding area with the primer per the primer manufacturer's instructions.

5. When the primer has dried and cured, apply the exterior grade acrylic latex paint, and blend into the surrounding area. It may require additional coats to achieve the desired color, consult the paint manufacturer's instructions.