Clamshell Building Replacement Panels & Weathershells
APPF Inc. fabricates drop-in replacement weathershells, door panels, end walls, and complete panel sets for all major Clamshell Building systems — System 50, System 80, Series D, and MegaDoor. Fabricated to original specifications. Direct fit for existing frames.
The Replacement Panel Problem — and the Solution
Clamshell Buildings Inc. — the original manufacturer of these structures — is no longer in operation. That means there is no OEM source for replacement panels. Facility managers and military logistics officers with aging structures face a real problem: the frames are sound, but the weathershell panels are deteriorating, and there is nowhere obvious to go for replacements.
APPF is the solution. We fabricate replacement panels using the same RF welding and industrial sewing processes used in the original structures. Our panels are fabricated to the original specifications — same dimensions, same seam construction, same attachment hardware pattern — so they are a direct fit for existing frames without modification.
We work from original drawings when available. When they are not — which is common for structures that have been in service for 20–30 years — we can develop specifications from field measurements or from existing panels. We have done this many times. It is a straightforward process.
Standard Replacement Weathershell
Direct replacement for the original PVC weathershell panels. Same dimensions, same RF-welded seam construction, same attachment hardware pattern. Drop-in fit for existing frames.
Insulated Replacement Panels
Upgrade from standard to insulated panels when replacing weathershells on climate-controlled facilities. Multi-layer construction with thermal barrier. Same exterior dimensions as standard panels.
Door Panel Replacements
Replacement roll-up, bi-fold, and personnel access door fabric assemblies. Fabricated to original door opening dimensions with matching attachment hardware.
End Wall Panels
End closure panels including personnel door cutouts, framing pockets, and attachment points. Fabricated to original end wall geometry.
Partial Panel Repairs
When only a section of a panel is damaged, APPF can fabricate a replacement section rather than a full panel — reducing cost and lead time for localized damage.
Full Tent Replacement Sets
Complete replacement panel sets for structures where the entire weathershell has reached end of service life. All panels fabricated as a matched set for consistent fit and appearance.
Replacement Panels by System
APPF fabricates replacement panels for all major Clamshell Building system configurations. Select your system below to see what panels are available.
System 50
The most widely deployed Clamshell Building system — used for aircraft hangars, LAMS shelters, drone facilities, and forward operating base structures. APPF fabricates replacement side panels, end walls, door panels, and ridge sections for all System 50 configurations including B-BBB, A-10, and VLAM variants.
Available replacement panels:
- Side wall weathershell panels
- End wall panels with door cutouts
- Ridge and peak panels
- Roll-up and bi-fold door panels
- Personnel access door panels
- Insulated and blackout variants
System 80
The large-span Clamshell Building system used for commercial airport hangars, ice rink covers, pool enclosures, and wide-body aircraft maintenance. System 80 panels are the largest format APPF produces. We fabricate replacement panels for aging structures and complete new assemblies for new construction.
Available replacement panels:
- Full-width side wall panels
- End wall and gable panels
- Translucent light-admitting panels
- Insulated panels for climate control
- Large-format door panel assemblies
- Custom configurations to drawing
Series D / MegaDoor
High-clearance Clamshell Building systems designed for C-130, wide-body, and heavy-lift aircraft. The Series D MegaDoor system uses a full-width fabric door panel that spans the entire hangar opening. APPF fabricates the complete fabric envelope including the MegaDoor panel assembly.
Available replacement panels:
- MegaDoor full-width door panels
- Side wall weathershell panels
- End wall panels
- High-clearance door assemblies
- C-130 and wide-body configurations
- Custom door panel systems
Custom & Non-Standard
Not all Clamshell Building structures match a standard system configuration. APPF can fabricate replacement panels for non-standard, modified, or custom structures. We work from customer-supplied drawings, field measurements, or existing panels — reverse-engineering the specification when original drawings are not available.
Available replacement panels:
- Reverse-engineered from existing panels
- Fabricated from field measurements
- Custom dimensions and configurations
- Modified system variants
- Specialty panel types
- Prototype and one-off panels
Structures We Fabricate Replacement Panels For
All major Clamshell Building system configurations — from System 50 aircraft hangars to System 80 pool enclosures and Series D MegaDoor facilities.
How to Order Replacement Panels
A straightforward process from first contact to delivery. No OEM required.
Contact APPF
Reach out by phone or email. Tell us the structure model (System 50, System 80, Series D, etc.), the panels needed, and your timeline.
Provide Drawings or Measurements
Supply original drawings if available. If not, we can work from field measurements or existing panels. We will confirm dimensions before fabrication.
Quote & Lead Time
We will provide a quote and estimated lead time based on panel type, quantity, and current production schedule.
Fabrication
Panels are RF-welded and industrially sewn in our Westminster, CA facility. Full traceability and documentation provided.
Delivery
Panels are packaged for shipping or pickup. We coordinate with your installation team on delivery timing.
Frequently Asked Questions — Replacement Panels
Common questions about ordering replacement panels and weathershells for Clamshell Building structures.
Ready to Replace Your Weathershell?
Contact APPF with your structure model and panel requirements. We will respond with a quote and lead time — no OEM required.