A primer on dome roofing and maintenance

Since 2008 FabricSpan has partnered with Dome Technology to create custom PVC airforms for concrete domes, offering a full range of maintenance services that keep domes looking sharp and watertight outside while preserving a stable environment inside. For a long dome lifespan, FabricSpan recommends these steps:

1. Inspections

Even though an airform resists UV damage and harsh weather, every airform will at some point require repairs, just like traditional roofing. The lifespan of the membrane is typically 15 to 20 years. Routine inspection and upkeep will help maintain quality to get the most out of your dome’s exterior.

We recommend annual inspections to ensure the PVC airform is free of damage and protecting the structure. Use the following checklist for your inspections:

  • Are there any tears or punctures in the fabric membrane?
  • Is polyurethane foam exposed?
  • Is the fabric membrane brittle and showing signs of cracking?
  • Is the membrane now chalky to the touch, unable to be “polished”?
  • Is the dome prone to leaking at penetrations, valleys, or other joints?
  • Do you have other concerns not listed above?

If you answered “yes” to any of these questions, our team can help you properly address issues before additional damage is done, possibly affecting the dome’s concrete infrastructure. Contact us at 208.552.6179 or email your concerns and photos to luke@fabricspan.com.

2. Cleaning

When the surface looks dirty, customers can clean the outer PVC airform with a few simple tools—mild detergents, soft brushes, and low-pressure water are all it takes to restore most membranes to original condition. High-powered pressure washing is discouraged and might remove the membrane’s protective coatings applied to maximize the lifespan.

3. Repairs

PVC-coated polyester fabric is durable and can last up to 20 years, but in the event of damage, customers can often make repairs themselves. For small repairs, FabricSpan provides instructions and mailed materials; in many cases, a simple heat-welded patch over the damaged area will be the only mending required.

For serious damage, FabricSpan experts can patch, coat, or even recover structures on site in the United States and abroad, depending on the circumstances and condition of the dome.

4. Reroofing

The airform material carries a 15-year prorated manufacturer warranty, but when the time comes for a replacement, select our team to tackle the job. Reroofing comes in two forms:

>> Fabric membrane panels:

This innovative recovering method incorporates fabric panels attached to a set of curving aluminum rails anchored across the dome surface. Pre-manufactured PVC membrane panels are tensioned and attached to the rails until the dome is entirely covered with new fabric panels.


  • Little to no surface preparation is required
  • Vented air space allows any saturated foam to dry
  • Aluminum hardware is more resistant to corrosion
  • PVC panel lifetime is comparable to or better than that of the original membrane
  • Individual panels can be replaced as needed
  • Membrane material carries 15-year prorated manufacturer warranty

>> Specialty elastomeric coatings: When the layer being coated is in sound structural condition, coating is a possibility. There are three options: 1) a simple new weathering surface, 2) a fast-set tougher coating that will boost structural integrity at the surface, or 3) a combination of the two with a tougher base coat and better weathering topcoat.

If coating is the right step for the project, the membrane will be cleaned to remove buildup, a test for adequate adhesion will be completed, and the primer and silicone coating will be added in multiple coats to provide a new “membrane” for the dome. Depending on the application, warranties range from 10 to 20 years.


  • Simpler application
  • Economical
  • Polyurea and silicone coatings are weather and chemical resistant
  • Fast-set coating renews surface integrity
  • Manufacturer warranty available for labor and materials with renewable warranty through manufacturer upon evaluation and recoating
  • Preserves existing airform and foam