When it comes to roofing, there are numerous materials and methods that homeowners and professionals must consider to ensure a durable and efficient roof. One of the frequently asked questions in the roofing industry, particularly in the UK, is whether shingles can be installed over wet felt. This question arises due to the unpredictable British weather, which often presents challenges during roofing projects. In this blog, we will delve into the intricacies of this topic, examining the materials involved, the implications of installing shingles over wet felt, and the best practices for roofing in the UK.
Understanding Roofing Felt and Shingles
Before addressing the main question, it's essential to understand what roofing felt and shingles are and their roles in a roofing system.
Roofing Felt
Roofing felt, also known as underlay, is a protective layer placed between the roof deck and the felt shingles. It is typically made from a base material (often a combination of fibreglass or polyester) saturated with bitumen (asphalt) to make it water-resistant. The primary functions of roofing felt include:
Moisture Barrier: It prevents moisture from reaching the roof deck.
Protection: It offers an additional layer of protection against wind and rain.
Temporary Waterproofing: It can temporarily protect the roof deck if shingles are delayed.
Felt Shingles
Shingles are the outermost layer of the roof and are responsible for the roof's aesthetic appeal and primary weather protection. In the UK, asphalt shingles are popular due to their durability, cost-effectiveness, and ease of installation. They come in various styles, colours, and materials, allowing homeowners to customise the appearance of their roofs.
The Importance of Dry Roofing Felt
The primary concern with installing shingles over wet felt revolves around the potential consequences of doing so. Here are the key reasons why roofing felt should be dry before shingle installation:
Moisture Entrapment
Wet felt can trap moisture between the felt and the roof deck. This trapped moisture can lead to several problems:
Rot and Mould: Moisture can cause the roof deck to rot and mould, compromising the structural integrity of the roof.
Shingle Adhesion: Wet felt can prevent felt roof shingles from properly adhering to the roof deck, leading to shingle blow-offs and leaks.
Insulation Issues: Moisture can seep into the insulation, reducing its effectiveness and leading to higher energy costs.
Reduced Lifespan
Roofing materials, including felt and shingles, are designed to perform best when dry. Wet felt can degrade more quickly, reducing the overall lifespan of the roof. This degradation can lead to more frequent repairs and replacements, increasing the long-term costs of roofing maintenance.
Compromised Installation
Installing shingles over wet felt can make the installation process more challenging. Wet felt is slippery, increasing the risk of accidents for roofers. Additionally, it can cause the shingles to buckle or warp, leading to an uneven and unattractive roof surface.
The British Weather Challenge
The UK's weather is notoriously unpredictable, with frequent rain and high humidity levels. This weather pattern can make it difficult to ensure that roofing felt remains dry during installation. Here are some strategies to manage this challenge:
Weather Monitoring
Before starting a roofing project, it's crucial to monitor the weather forecast. Choose a period with the least likelihood of rain to minimise the risk of wet felt. While perfect weather conditions are rare, aiming for a dry spell can make a significant difference.
Temporary Coverings
If rain is unavoidable, consider using temporary coverings such as tarpaulins or plastic sheeting to protect the felt from getting wet. These coverings can shield the roof deck and felt during rain showers and be removed once the weather improves.
Rapid Installation
Another approach is to work efficiently to minimise the time the felt is exposed. Prepare all materials and tools in advance to ensure the shingles can be installed as quickly as possible after the felt is laid. This rapid installation reduces the window of opportunity for the felt to become wet.
Professional Advice and Regulations
When in doubt, it's always best to seek professional advice. Experienced roofers in the UK are familiar with local weather patterns and best practices for roofing installations. They can provide guidance on timing, materials, and techniques to ensure a successful roofing project.
Building Regulations
In the UK, building regulations set standards for construction projects, including roofing. These regulations are designed to ensure safety, health, and energy efficiency. While there are no specific regulations that address installing shingles over wet felt, adhering to general roofing standards is crucial. These standards include:
Proper Ventilation: Ensuring the roof has adequate ventilation to prevent moisture buildup.
Quality Materials: Using high-quality roofing felt and shingles that meet industry standards.
Correct Installation: Following manufacturer guidelines and industry best practices for installation.
Alternatives to Asphalt Felt Shingles
For those concerned about the challenges of installing shingles over wet felt, there are alternative roofing materials that might be more suitable for the UK climate. Some options include:
Metal Roofing
Metal roofing is highly durable and can withstand harsh weather conditions. It is also less prone to water damage and mould growth compared to traditional shingles. Metal roofs can be installed over a variety of underlay materials, providing flexibility in wet conditions.
Slate Tiles
Slate is a natural stone that is highly resistant to moisture and has a long lifespan. It is an excellent choice for areas with frequent rain, as it does not absorb water like asphalt shingles. However, slate is more expensive and requires professional installation.
Rubber Roofing
Rubber roofing, often made from recycled materials, is another durable option. It provides excellent waterproofing and can be a good choice for flat or low-slope roofs. Rubber roofing is relatively easy to install and maintain, making it a practical option for many homeowners.
Conclusion
While it might be tempting to install shingles over wet felt to keep a roofing project on schedule, the potential risks and long-term consequences make it a poor choice. Moisture entrapment, reduced material lifespan, and compromised installation are significant issues that can arise from this practice. In the UK, where weather conditions are often unpredictable, it is crucial to plan roofing projects carefully and take preventive measures to keep roofing felt dry.
By monitoring the weather, using temporary coverings, and working efficiently, homeowners and roofers can minimise the risk of installing shingles over wet felt. Additionally, seeking professional advice and adhering to building regulations ensures a successful and durable roofing project. Considering alternative roofing materials that are more resilient to moisture can also be a prudent choice for those concerned about the challenges posed by the British climate.
Ultimately, patience and proper planning are key to achieving a high-quality roof that will protect your home for years to come. Avoid the shortcuts and take the necessary steps to ensure your roofing felt is dry before installing shingles. Your roof—and your wallet—will thank you in the long run.
