How To Build Frame To Increase Roof Thickness On 1973 Airstream For Chill Cube Installation

Updated 03/11/2026 | Published 03/08/2026

Question:

I am reading the answer to the question about installing a chill cube on an earlier Airstream. Can you give any more detailed guidance on building the frame to increase the thickness of the roof on a 1973 Airstream for installation of the chill cube.

asked by: Jim A

Expert Reply:

Hey Jim, thanks for reaching out, and great question. The Furrion Chill Cube # FR59TD requires a roof thickness between 3-1/2" and 6" so the mounting bolts can properly clamp and seal. Most vintage Airstream roofs are thinner than that, so you’ll need to build up a reinforced frame inside the roof opening rather than just stacking material on top.

The cleanest way to do this is to frame the 14" by 14" opening with kiln-dried hardwood or quality plywood blocking that matches the curvature of the roof. Many installers laminate plywood layers to reach the needed thickness, shaping the top layer slightly to follow the roof contour so the AC gasket compresses evenly. The frame should tie into the existing roof bows, not just the thin aluminum skin, so the load is spread across the structure, and you avoid flex. Use butyl tape under the AC gasket and a compatible self-leveling sealant around the exterior flange to prevent leaks.

Hope this helps! Let me know if there is anything else I can do.

expert reply by: Jesse M