Roofing felt, also known as underlayment, is a crucial component in the construction of a roofing system. It is placed between the roof deck and the final roofing material to provide an extra layer of protection against moisture, wind, and other environmental elements. However, one common dilemma that homeowners and contractors face is whether it is safe to install roofing felt on damp decking. In this article, we will discuss the implications and considerations of installing roofing felt on damp decking.
Understanding Roofing Felt and Its Purpose
Roofing felt is a type of synthetic material, often made of fiberglass, polyester, or bitumen-coated felt, which is commonly used as an underlayment. It acts as a moisture barrier, preventing water from penetrating the roof assembly and causing damage to the underlying structure. Additionally, roofing felt helps to reduce heat loss, provide a smooth surface for shingle installation, and offer temporary protection during the roofing process.
Dangers of Installing Roofing Felt on Damp Decking
While roofing felt is designed to withstand moisture to a certain degree, installing it on damp decking can pose several risks. Moisture trapped between the roof deck and the felt can lead to mold and mildew growth, compromising the integrity of the roof system. Additionally, damp decking may not allow the proper adhesion of the felt, leading to lifting or wrinkling, which can affect the overall performance of the roofing system.
Proper Deck Preparation
It is crucial to ensure that the decking is dry and in good condition before installing roofing felt. Here are some steps to follow when preparing the deck for felt installation:
- Remove existing moisture: If the decking is damp, it is essential to allow it to dry thoroughly before proceeding with the installation. Use fans or dehumidifiers to expedite the drying process. Avoid installing any materials until the moisture content is within acceptable limits.
- Check for damage: Inspect the decking for any signs of rot, decay, or other structural issues. Repair or replace damaged sections before installing the roofing felt to ensure a solid foundation for the entire roofing system.
- Provide proper ventilation: Adequate ventilation is crucial to prevent moisture buildup on the deck. Install vents or exhaust fans in the attic or roof space to promote air circulation and prevent condensation that can lead to damp decking.
Installing Roofing Felt
Once the deck is dry and in good condition, you can proceed with the installation of roofing felt. Follow these guidelines to ensure a proper installation:
- Choose the right underlayment: Select a roofing felt that is suitable for your specific climate and roofing material. Different types of felt have different ratings for water resistance and durability. Consult with a roofing professional to determine the best option for your project.
- Use a quality adhesive: Apply a high-quality adhesive approved by the manufacturer to secure the roofing felt to the deck. This will provide a strong bond and minimize the risk of lifting or wrinkling, even in damp conditions.
- Overlap correctly: Overlap the roofing felt according to the manufacturer’s guidelines to ensure adequate coverage and prevent water infiltration. Proper overlap is crucial in keeping moisture away from the decking.
Installing roofing felt on damp decking can lead to various issues such as mold growth, poor adhesion, and compromised performance of the roof system. It is crucial to ensure that the deck is dry and in good condition before proceeding with the installation. Taking the necessary steps to prepare the deck and choosing the right underlayment will help ensure a successful and durable roofing system. Consult with a roofing professional for expert guidance and to address any specific concerns related to your project.