Common DIY Mistake:<\/strong> Many people try to “nail only.” Without adhesive at the seams, wind will eventually lift the edges, and capillary action will pull water right under the felt and into your plywood.<\/p>\n\n\n\n90 Pound Roofing Felt vs. Modified Bitumen<\/h2>\n\n\n\n
We often get asked: “Is this #90 felt or Modified Bitumen (Mod Bit)?” They look very similar because they both come in granulated rolls. However, they are very different beasts.<\/p>\n\n\n\n
The Tear Test:<\/strong>\nThe easiest way to tell them apart is to try and tear a small piece. 90 pound roofing felt<\/strong> is made with a fiberglass or organic mat; it is relatively brittle and will tear if you pull hard enough. Modified Bitumen<\/strong> is “modified” with rubber (SBS) or plastic (APP) polymers. It is extremely stretchy and almost impossible to tear by hand.<\/p>\n\n\n\nComparison at a Glance:<\/strong><\/p>\n\n\n\n\n- Underside:<\/strong> Mod Bit usually has a glossy black, smooth underside (especially the torch-down or peel-and-stick versions). #90 felt usually has a duller, asphalt-saturated finish.<\/li>\n
- Durability:<\/strong> Mod Bit can last 15\u201320 years. #90 felt typically lasts 5\u201310 years.<\/li>\n
- Installation:<\/strong> Mod Bit often requires a torch or is self-adhered. #90 felt is usually “mopped” or glued.<\/li>\n
- Price:<\/strong> 90 pound roofing felt<\/strong> is significantly cheaper, making it the “budget” choice for utility structures.<\/li>\n<\/ul>\n\n\n\n
Pros, Cons, and Limitations<\/h2>\n\n\n\nUsing 90 Pound Roofing Felt as a Standalone Surface<\/h3>\n\n\n\n
Is it right for your project? Let\u2019s weigh the options.<\/p>\n\n\n\n
The Pros:<\/strong><\/p>\n\n\n\n\n- Cost-Effective:<\/strong> It is one of the cheapest ways to cover a low-slope roof.<\/li>\n
- DIY Friendly:<\/strong> Unlike torch-down roofing (which can literally burn your house down if you aren’t careful), #90 felt can be installed with basic tools and cold adhesive.<\/li>\n
- Availability:<\/strong> You can find it at almost any hardware store in Salt Lake City or Davis County.<\/li>\n
- Breathability:<\/strong> Organic-based felts allow some moisture to escape the building, reducing the risk of rot in certain conditions.<\/li>\n<\/ul>\n\n\n\n
The Cons:<\/strong><\/p>\n\n\n\n\n- Short Lifespan:<\/strong> In the harsh Utah sun and snow, don’t expect more than 10 years. On flat roofs with ponding water, it might only last 5.<\/li>\n
- Maintenance:<\/strong> You need to check the seams every year. If the adhesive dries out and cracks, leaks follow immediately.<\/li>\n
- Fragility:<\/strong> It becomes brittle in the winter. If you walk on it when it\u2019s freezing, you can crack the membrane.<\/li>\n
- UV Sensitivity:<\/strong> Once the granules start to rub off (granule loss), the asphalt underneath degrades rapidly under UV light.<\/li>\n<\/ul>\n\n\n\n
Frequently Asked Questions about 90lb Felt<\/h2>\n\n\n\nIs 90-pound roofing felt the same as underlayment?<\/h3>\n\n\n\n
No. While it has the word “felt” in the name, it is a roll roofing membrane<\/strong>. Standard underlayment (like #15 or #30) is meant to be covered by shingles. 90-pound felt is meant to be the final, exposed layer of the roof. Using it as an underlayment is generally a waste of money and can create a surface that is too “slick” for shingles to bond to properly.<\/p>\n\n\n\nCan you install 90-pound felt over an existing roof?<\/h3>\n\n\n\n
While some people do it, we don’t recommend it. Installing new #90 over an old, wrinkled roof will result in a “telegraphed” finish\u2014meaning the new roof will be just as lumpy as the old one. This creates water pockets and speeds up failure. It\u2019s always better to tear off the old material to inspect the wood deck for rot.<\/p>\n\n\n\n
How do you identify 90-pound felt on an existing structure?<\/h3>\n\n\n\n
Look at the seams and the texture. If it’s a 3-foot wide roll with mineral granules and it feels somewhat “papery” or brittle when you pick at an edge, it\u2019s likely 90 pound roofing felt<\/strong>. If it feels rubbery and thick, you\u2019re likely looking at Modified Bitumen.<\/p>\n\n\n\nConclusion<\/h2>\n\n\n\n
90 pound roofing felt<\/strong> is a reliable, budget-friendly solution for low-slope utility buildings, sheds, and porches. It provides a finished look that matches your shingles without the complexity of a commercial roofing system. However, its performance depends entirely on the quality of the installation\u2014specifically how well those seams are sealed.<\/p>\n\n\n\nAt M&M Gutters & Exteriors, we\u2019ve spent over 30 years serving Salt Lake City and the surrounding counties. We know that a roof is only as good as its weakest point. Whether you\u2019re looking for a quick shed roof or a full residential replacement, we bring the expertise and 3D visualization tools to ensure the job is done right the first time.<\/p>\n\n\n\n
Don’t leave your low-slope roof to chance. If you’re in Northern Utah and need a professional eye on your next project, reach out to us today.<\/p>\n\n\n\n
Get a quote for professional roofing services<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"Discover 90 pound roofing felt: specs, installation, pros\/cons vs. modified bitumen. Ideal for low-slope roofs\u2014standalone or underlayment?<\/p>\n","protected":false},"author":4,"featured_media":9208,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_et_pb_use_builder":"","_et_pb_old_content":"","_et_gb_content_width":"","inline_featured_image":false,"footnotes":""},"categories":[9],"tags":[34],"class_list":["post-9209","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-general","tag-gutter-system"],"_links":{"self":[{"href":"https:\/\/avalaunchsites.com\/mandmgutters\/wp-json\/wp\/v2\/posts\/9209","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/avalaunchsites.com\/mandmgutters\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/avalaunchsites.com\/mandmgutters\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/avalaunchsites.com\/mandmgutters\/wp-json\/wp\/v2\/users\/4"}],"replies":[{"embeddable":true,"href":"https:\/\/avalaunchsites.com\/mandmgutters\/wp-json\/wp\/v2\/comments?post=9209"}],"version-history":[{"count":0,"href":"https:\/\/avalaunchsites.com\/mandmgutters\/wp-json\/wp\/v2\/posts\/9209\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/avalaunchsites.com\/mandmgutters\/wp-json\/wp\/v2\/media\/9208"}],"wp:attachment":[{"href":"https:\/\/avalaunchsites.com\/mandmgutters\/wp-json\/wp\/v2\/media?parent=9209"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/avalaunchsites.com\/mandmgutters\/wp-json\/wp\/v2\/categories?post=9209"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/avalaunchsites.com\/mandmgutters\/wp-json\/wp\/v2\/tags?post=9209"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
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