Converting American RV Motorhome Roofs from Aluminium to Fibreglass

Converting American RV Motorhome, in the early 2000s, American RV manufacturers made a significant shift in their roofing approach. Between 2001 and 2004, many moved away from rubber roof membranes, opting instead for aluminium coverings. This change was primarily driven by the desire to address persistent leakage issues that had been plaguing the industry. At first glance, this seemed like a promising solution to an escalating problem.

The Rationale Behind Aluminium Roofs

Aluminium, as a roofing material, offered several apparent advantages. Most importantly, it could be painted white, reflecting heat and potentially improving the RV’s energy efficiency. This reflective property also had an aesthetic benefit: it eliminated the unsightly white streaks that often appeared on RV paintwork when rubber roofs weren’t regularly maintained.

Furthermore, aluminium’s malleability allowed manufacturers to create profiled roofs. This design feature enabled rainwater to be channeled effectively down gutters on either side of the motorhome, potentially reducing the risk of water pooling and subsequent leaks.

The Unforeseen Challenge: Thermal Bridging

However, despite these perceived benefits, manufacturers overlooked a crucial factor: thermal bridging. This phenomenon occurs when there’s a significant temperature difference between the interior and exterior of a structure, causing condensation to form on the cooler surface.

To better understand this concept, consider your car windows on a cold day. Initially, they’re clear, but as you warm up the interior, moisture begins to appear on the glass. This same principle applies to aluminium RV roofs, but with more severe consequences.

The Problematic Effects of Thermal Bridging

Converting American RV Motorhome, in the context of RV roofs, thermal bridging became a substantial and costly issue. As the cold exterior environment cooled the outer surface of the aluminium, the lack of adequate insulation led to moisture formation on the interior side of the roof. This moisture then seeped into the wooden understructure, gradually causing rot in the roof members.

The effects of this thermal bridging were so pronounced that many RV owners mistakenly believed they were dealing with rainwater leaks. In some cases, the damage was extensive enough to convince owners that their roofs were actively leaking during rainy weather.

Addressing the Aluminium Roof Problem

One potential solution to this issue would have been to fully insulate the underside of the roof and bond the aluminium outer sheets to the wooden structure. Unfortunately, in many cases, this crucial step was overlooked during the manufacturing process.

As time passed, these problems became increasingly apparent. With high-quality rear-engine RV pushers becoming harder to find, repairing existing models became a viable option for many owners.

The Fibreglass Solution: A Case Study

At LAS Motorhome, we recently tackled this problem for a customer. After careful consideration, we determined that the best course of action was to rebuild the roof entirely and recover it with fibreglass. This process involves several key steps:

1. Complete Roof Stripping: The first step is to completely strip back the roof, removing all existing materials.
2. Damage Assessment: Once exposed, we can fully assess the extent of the damage caused by thermal bridging.
3. Reconstruction: After removing damaged materials, we begin rebuilding the roof structure.
4. Insulation Installation: We install new, high-quality insulation to prevent future thermal bridging issues.
5. Fibreglass Application: Finally, we apply a fibreglass covering, creating a durable and weather-resistant roof.

The Conversion Process: A Closer Look

To better understand the conversion process, let’s examine it step by step:

1. Initial Inspection: Upon removing a piece of aluminium, we often find damp patches, indicating the severity of the thermal bridging effect.
2. Full Aluminium Removal: After removing all aluminium, the true extent of the damage becomes apparent. While it may not look severe from a distance, closer inspection reveals significant issues.
3. Uncovering the Damage: As we remove the underwood covering, we expose the polystyrene insulation beneath. Often, the most severe damage is found in living areas, supporting the thermal bridging theory as these are typically the warmest parts of the RV.
4. Insulation Replacement: We remove the old insulation and replace it with new, more effective materials.
5. Structural Rebuild: We cover the new insulation with sheets of plywood, creating a flat, stable surface.
6. Roof Profiling: We then construct a new roof profile, similar to the original design but with improved materials and techniques.
7. Additional Insulation: To prevent potential thermal bridging in the spaces between the new profile, we drill holes and inject insulation foam. This not only improves insulation quality but also enhances the overall rigidity of the structure.
8. Fibreglass Application: Finally, we apply the fibreglass covering. The result is a seamless roof with a profile identical to the original, but with far superior insulation and durability.

Benefits of Fibreglass Roofs

Converting to a fibreglass roof offers several significant advantages:

1. Improved Insulation: Fibreglass, combined with proper insulation techniques, dramatically reduces the risk of thermal bridging.
2. Durability: Fibreglass roofs are highly resistant to weather damage and can last for many years with proper maintenance.
3. Leak Resistance: The seamless nature of a fibreglass roof significantly reduces the risk of leaks.
4. Energy Efficiency: Better insulation means improved temperature regulation inside the RV, potentially leading to energy savings.
5. Value Retention: A well-maintained fibreglass roof can help preserve the value of your RV over time.

Conclusion

The transition from aluminium to fibreglass roofs represents a significant improvement in RV construction. While aluminium seemed like a good solution initially, the unforeseen consequences of thermal bridging have led to the need for better alternatives. Fibreglass, when properly installed with adequate insulation, offers a superior solution that addresses these issues effectively.

For RV owners dealing with aluminium roof problems, converting to fibreglass can be a worthwhile investment. It not only solves existing issues but also prevents future problems, potentially saving money on repairs in the long run. Moreover, it enhances the overall comfort and energy efficiency of your RV.

If you’re considering converting American RV Motorhome roof conversion, it’s crucial to work with experienced professionals who understand the intricacies of this process. At LAS Motorhome, we have the expertise to handle these complex conversions, ensuring your RV roof is built to last.

For more information or to discuss your RV roof conversion needs, don’t hesitate to contact LAS at 01604 861999. Our team of experts is ready to help you improve your RV and enhance your travel experiences.