When homeowner Maarten Sengers embarked on a roof replacement project at his Washington, D.C. residence, he faced a unique challenge. The home’s attic had been encapsulated with closed-cell spray foam directly beneath the roof deck—an effective insulation method, but one that created heat and moisture complications for the asphalt shingles above.
Without ventilation beneath the roof deck, the shingles were experiencing excessive heat buildup, and any trapped condensate had no way to vaporize and escape. These “hot roof” conditions not only reduced shingle lifespan but also raised long-term maintenance concerns.
The Solution: Viper Vent™ CDR
Architect Hugo Roell introduced Maarten to Viper Vent™ CDR, a product designed to deliver continuous airflow beneath asphalt shingles while maintaining a low-profile installation. When re-roofing the home, Maarten integrated Viper Vent CDR along with new roofline ventilation to restore balanced airflow and address both heat and moisture concerns.
“This was a simple and relatively low-cost way—without added weight—of adding ventilation under the asphalt shingles,” Maarten explained. “Based on initial temperature measurements, we estimate the product reduced roof surface temperature on hot, sunny days by at least 25 degrees.”
Performance and Results
By incorporating Viper Vent CDR, the roof now benefits from:
- Improved airflow beneath asphalt shingles
- Reduced roof surface temperatures
- Enhanced shingle longevity
- An escape path for moisture and condensate vapor
The result is a high-performing, well-ventilated “hot roof” system that preserves the energy efficiency benefits of spray foam while resolving the ventilation and heat challenges often associated with it.
Partnership with Keene Building Products
Throughout the project, Maarten worked closely with Bill Griffith and Dan Festa of Keene Building Products for technical guidance and site support.
“Bill and Dan helped clarify that the proposed use and installation were appropriate and answered various technical questions,” Maarten shared. “Bill even visited the site and stayed in active communication. It was a simple, cost-effective solution to the problems we faced—and I’m very happy that a product like this was available.”
Conclusion
The Washington, D.C. roof renovation demonstrates how Viper Vent™ CDR provides a practical and efficient solution for homeowners facing the unique challenges of spray-foam-insulated roofs. With the right product and expert support from Keene Building Products, even complex moisture and heat concerns can be resolved with confidence.
