Is Roofing Felt Necessary for My Property?

Insulation, Membranes & Felts
roof felt being fitted

Even though felt has been used in the construction of our roofs for over one hundred years, there are still many questions raised over its actual purpose – beyond adding cost. You may be wondering if this cost is truly needed, especially when refurbishing or replacing your roof entirely. Below, we'll go through just what this material is for, what benefits it provides, the associated costs involved and – most importantly – whether you'll need it for your next project.

What is Roofing Felt?

Sometimes known as tar paper, roof felt provides a simple covering across the deck of your roof, made from a base of natural or synthetic materials and then coated with an additional protective layer such as bitumen. Beyond simply offering a stable surface to work off, once installed it also provides additional protection from the weather – helping to keep your home dry and mould-free. Of course, this is all but essential when the time comes to perform maintenance, especially so if this maintenance is blocked to take days or weeks.

Perhaps one of the best examples of its practical use can be seen when installing new shingles. In the gap between removing the old and replacing with the new, this barrier keeps water damage to a minimum, ensuring that the new roof can perform as well as, or better, than the old.

Other Benefits of Roofing Felt

That being said, many homes do not and have never had felt installed. With an adequate covering, the absence may not be noticed. At least, initially. Much like airbags, you may not need them to get the car running but you'll certainly miss them if you crash. Here are just some of the benefits that you may be losing out on without roofing felt installed.


We hardly need to mention the temperamental nature of our British weather. Rain can come at any time of the day and night, often when it is most inconvenient. This, in addition to snow and sleet, is the number one killer of unprepared roofs. Whilst obviously disastrous if your roof is exposed at the night, persistent water can easily get through cracks or gaps in your tiles (especially so if they are old or damaged) and into the roof below.

Without a protective underlayment, this water will play havoc with the rafters underneath. In the worst case, causing hundreds if not thousands of pounds worth of damage. Roofing felt greatly helps in curbing these risks, designed specially to allow water to drain off your roof where it can harmlessly drift into drains or plants.

Second Layer of Defence

Not even the best tiles and slates are completely infallible. When confronted with snow build-up or other extreme weather conditions, they are liable to lift or crack. Even the smallest piece of damage can lead to a leak, so it is important to be prepared for the worst.

In the case of snow and ice collecting in your gutters or on your tiles, it is all too common for the heat released from your home to cause them both to melt. This excess of water can often be found seeping through your covering and, if not for felt, directly onto the wooden structure underneath. This is much the same if a tile is lifted by the wind, providing easy access for direction rain blown in by a storm.

Uniform Appearance

Yes, stopping water and rain is not all that roofing felt can do. In fact, a properly installed underlayment can help ensure maximum curbside appeal. Simply put, it provides a sort of canvas for roofers to work from. A flat surface which helps ensure all the tiles or shingles can be kept in line and uniform.

Prevents Resin Stains

When building a new roof deck, you may find that any stains used can, over time, seep into the coverings above. Fast-forward a few years and you might end up with a roof that actually detracts from the overall value of your home, leading to potential costly replacements should you want the issue resolved. Roofing felt prevents this, acting as a blocker to prevent the stain from leeching upwards

How Much Does Roof Felt Cost?

Like any roofing job, the exact price will depend on several factors, not least of which is labour costs. That being said, most smaller patch jobs clock in around the £200 mark. If you are looking to fit felt across a new roof (or replace yours completely) this can be anywhere between £2000 and £8000, depending on the size of your roof and whether or not you need your tiles replaced as well. Needlessly to say, this is not a job we would recommend taking on DIY. Should this be a job you still want to undertake, however, always take care to consult a professional who should be able to help you find the best materials for your budget.

Vapour Control Layers & Roofing Membranes

Whilst felt provides numerous benefits, it is just one part of a wider system. After all, once your tiles or slates are fitted there will be dozens of fixings hammered into the material, creating dozens of holes for water to ingress through. So, whilst the temporary and limited protection is phenomenal, more specialised layers may also be needed to provide additional support. Specialised layers, including VCLs and Breathable Membranes.

These can help by restricting the movement of warm, moist air inside your roof (limiting the risks of mould and mildew) as well as promoting healthy airflow and ventilation. Some breathable membranes are also completely waterproof.

Any More Questions about Roofing Felt?

Whether you’re looking to fit some new felt or are in need of a quick repair, our award-winning customer service team is here to help. From picking out the perfect products to simple advice and support, we’re here to get your project off to a flying start. Simply call us on 01295 565565 or talk to us now using the chatbox below.

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