How to Lay Roofing Felt: A Step-by-Step Guide

How to Lay Roofing Felt: A Step-by-Step Guide
Written by
Roofing Pros Liverpool
Published on
February 9, 2024

Laying roofing felt is an essential part of any DIY roofing project, whether it's for a shed or a flat roof. Roofing felt is a type of material that protects the roof decking from water damage. It is a durable and affordable option that can be installed with ease. In this article, we will provide a step-by-step guide on how to lay roofing felt, so you can complete your DIY roofing project with confidence.

Roofing felt is rolled out across the roof, starting from the bottom and working upwards. It is then secured with nails or staples to ensure it is firmly in place

Before you begin, it's important to gather all the necessary tools and materials. This includes roofing felt, felt adhesive, tape measure, galvanised nails, a paintbrush for use with the adhesive, and gravel (optional). Once you have everything you need, you should properly prepare the old roof by removing any old pieces of felt, checking for damage to the roof or timber, and making any necessary repairs.

Once the old roof is properly prepared, you can begin installing the new roofing felt. The process involves laying the felt, securing it with nails or staples, and ensuring that it is properly sealed. By following the steps outlined in this article, you can ensure that your roofing felt is installed correctly, providing your roof with the protection it needs for years to come.

Preparation and Safety

Roofing felt laid out on clean, dry surface. Safety gear nearby. Hammer and nails ready

Before starting to lay roofing felt, it is crucial to assess the roof surface to ensure that it is clean, dry and free from any debris or sharp objects that could damage the felt. It is also important to gather all the necessary tools and materials and take necessary safety precautions to avoid any accidents.

Assessing the Roof Surface

The first step in preparing to lay roofing felt is to assess the roof surface. It is important to ensure that the roof surface is clean, dry and free from any debris or sharp objects that could damage the felt. The roof deck should be made of plywood or decking that is in good condition and free from any rot or damage. If there are any areas of the roof deck that are damaged, they should be replaced before laying the felt.

Gathering Necessary Tools and Materials

To lay roofing felt, you will need a number of tools and materials. These include:

  • Roofing felt
  • Nails
  • Hammer
  • Utility knife
  • Measuring tape
  • Chalk line
  • Roofing adhesive

It is important to make sure that you have all the necessary tools and materials before starting to lay the felt. This will help to ensure that the job runs smoothly and that you do not have to stop partway through to gather additional materials.

When working on a roof, it is important to take necessary safety precautions. This includes wearing appropriate safety gear such as non-slip shoes, gloves and a safety harness. It is also important to work on the roof during dry weather conditions and to avoid working on the roof alone.

By following these preparation and safety steps, you can ensure that your roofing felt is laid correctly and that the roof is safe and secure.

Installation Process

Roofing felt laid over plywood, secured with nails.Overlap edges by 2 inches. Smooth out any wrinkles or bubbles

Installing roofing felt is a crucial step in ensuring the longevity of a roof. The process can be completed by following a few simple steps.

Laying the First Layer

The first step in installing roofing felt is to lay the first layer. Begin at the lowest edge of the roof and roll out the felt perpendicular to the full. Cut the felt accordingly once you have established how much you need. Ensure that the felt is aligned with the roof edge and extends past the edge by a minimum of 50mm.

Aligning and Overlapping Felt

Once the first layer is laid, align and overlap the subsequent layers. Ensure that each layer overlaps the previous layer by a minimum of 75mm. This will prevent any water from seeping through the gaps between the layers. Use felt adhesive to secure the overlaps.

Securing the Felt

The final step is to secure the felt to the roof. Use galvanised clout nails to secure the felt to the roof deck. Place the nails in a straight line along the course of the felt, ensuring that they are spaced 150mm apart. Use a hammer to secure the nails to the roof.

In conclusion, the installation process of roofing felt is a simple yet crucial step in ensuring a long-lasting roof. By following the above steps, one can ensure that the felt is installed correctly and will provide adequate protection against the elements.

Finishing Touches

After laying the roofing felt, it's time to complete the finishing touches to ensure a professional and long-lasting finish. Here are some essential steps to follow:

Trimming Excess Felt

Once the roofing felt has been laid, it's essential to trim any excess felt from the edges. Use a sharp knife or scissors to cut the felt to the correct size. Be sure to leave a slight overhang of around 50mm at the eaves, ridge, and gable ends. This overhang will be trimmed later to ensure a neat finish.

Installing Additional Features

To ensure maximum protection against the elements, it's essential to install additional features such as trim, flashing, shingles, drip edge, verge, and vent pipes. Here are some tips on how to install these features:

  • Trim: Use metal or plastic trim to cover the edges of the roof and provide extra protection against water ingress. Secure the trim in place using roofing nails or screws.
  • Flashing: Install flashing around chimneys, vents, and other protrusions to prevent water from seeping in. Use a sealant to ensure a watertight seal.
  • Shingles: Install shingles over the roofing felt to provide extra protection against the elements. Use roofing nails to secure the shingles in place.
  • Drip edge: Install a drip edge along the eaves to direct water away from the roof and prevent damage to the fascia board. Secure the drip edge in place using roofing nails or screws.
  • Verge: Install a verge along the gable ends to provide extra protection against the elements. Secure the verge in place using roofing nails or screws.
  • Vent pipes: Install vent pipes to allow air to circulate in the roof space and prevent moisture buildup. Use a sealant to ensure a watertight seal around the vent pipe.

By following these steps, you can ensure that your roofing felt is installed correctly and will provide long-lasting protection against the elements.

Maintenance and Repair

Regular maintenance and repair of roofing felt is essential for protecting the roof and the building from damage. Proper maintenance can also extend the life of the roofing felt, saving you money in the long run. This section will cover how to inspect for damage and execute repairs.

Inspecting for Damage

Inspecting the roofing felt for damage is an important step in maintaining the roof. The following are some signs of damage to look out for:

  • Tears or cuts in the felt
  • Bubbles or blisters in the felt
  • Strips of felt that have come loose or have been blown off by the wind
  • Debris or moisture trapped under the felt
  • Old felt that has worn thin or become brittle

It is important to inspect the roof after heavy rain or wind, as these conditions can cause damage to the roofing felt. Regular inspections should be carried out at least once a year.

Executing Repairs

If damage is found during the inspection, repairs should be executed promptly to prevent further damage to the roof. The following are some tips for executing repairs:

  • Cut out the damaged section of felt with a sharp knife or scissors, making sure to remove any debris or moisture underneath.
  • Replace the damaged section with a new piece of felt, making sure to overlap the existing felt by at least 75mm.
  • Use a patch repair kit to cover any tears or cuts in the felt. These kits are available from most DIY stores and are easy to use.
  • Ensure that the new felt is properly waterproofed by using a waterproofing solution or sealant.
  • If the damage is extensive or the felt is old and worn, it may be necessary to replace the entire roof with new felt.

By following these maintenance and repair tips, you can protect your roof and building from damage and ensure that the roofing felt remains durable and long-lasting.

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