What is roll roofing?

Roll roofing is a roofing material made of the same asphalt saturated base as shingles, but supplied in long, wide rolls rather than individual shingles, and installed in overlapping horizontal courses across a roof. It is essentially a large, continuous version of shingle material, which makes it fast and simple to put down over a big area, and it is one of the most economical roofing options there is. Most roll roofing has a mineral granule surface like a shingle, and it comes in rolls typically about three feet wide and long enough to cover a good stretch of roof in one pass, so a small roof can be covered quickly with relatively few pieces.

Roll roofing is designed for low slope roofs, the kind of shallow pitch where regular shingles will not shed water reliably, which makes it the go to choice for utilitarian structures like sheds, garages, porches, and other outbuildings. It is not meant for a main house roof, both because it does not last as long as shingles or a proper membrane and because its flat, seamed appearance is not attractive enough for a home. But for a low slope shed or a budget outbuilding, roll roofing does exactly what is needed, keeps the weather out, cheaply and simply, which is why it remains a popular DIY roofing material.

Types of roll roofing

There are a few varieties of roll roofing, and knowing them helps you choose the right one. The most common is mineral surfaced roll roofing (MSR), which has the granule coated surface like a shingle and is used as the exposed, finished roofing on low slope roofs. It can be installed with the fasteners exposed (nailed through the surface, the simplest method) or concealed (with the nails covered by the overlap and sealed, a more weathertight approach). Double coverage roll roofing has a wider selvage edge that allows each course to overlap the one below by half, giving two layers of coverage across the whole roof for better protection, at the cost of covering less area per roll.

There is also smooth or saturated felt roll used as underlayment rather than a finished surface, which is a different product from the mineral surfaced roll roofing used as the actual roof covering. For a shed or outbuilding you want a mineral surfaced roll roofing as the finished, exposed layer. The choice between exposed fastener and concealed fastener installation, and between single and double coverage, comes down to how weathertight and long lasting you need it versus how simple and cheap, with double coverage and concealed fasteners lasting longer and single coverage exposed fasteners being the quickest and cheapest.

When to use roll roofing

Roll roofing is the right choice in specific situations and the wrong one in others, so it helps to be clear about where it fits. Use it on low slope roofs, generally a pitch of about 2 in 12 up to where shingles become viable, on utilitarian structures where cost and simplicity matter more than appearance or maximum longevity: sheds, detached garages, porch roofs, workshops, barns and similar outbuildings. In these cases roll roofing is inexpensive, fast to install, and entirely adequate for the job, and it is a genuinely good DIY project on a small low slope roof.

Do not use roll roofing on your main house roof or anywhere appearance and long life are priorities. On a steep roof, shingles are the better and more attractive choice, as our asphalt shingle guide covers. On a larger or more important low slope roof, a proper membrane system like TPO or EPDM lasts far longer and performs better than roll roofing, as our flat roofing guide explains. Roll roofing occupies a specific niche, cheap, simple, low slope, utilitarian, and within that niche it is an excellent, practical choice, but it is not a substitute for shingles or a real membrane where those belong.

How to install roll roofing

Cost and lifespan

Roll roofing’s biggest advantage is its low cost. It is one of the cheapest roofing materials available, both in material and in labor, since it covers area quickly and is simple to install, which is exactly why it is favored for budget projects and outbuildings. On a small shed the total material cost is often very modest, and because it is DIY friendly on a low slope, you can save the labor entirely. That low cost is the whole appeal, and for a utilitarian structure where you simply need to keep the weather out affordably, it is hard to beat.

The tradeoff for that low cost is a shorter lifespan. Roll roofing typically lasts about 5 to 15 years, considerably less than shingles at 15 to 30 or a membrane at 20 to 30, because it is a thinner, single layer material more exposed to the elements, especially in the exposed fastener installation where the nail heads are weather points. Double coverage and concealed fastener installations last toward the longer end of that range. So roll roofing trades longevity for cost and simplicity, which is a perfectly sensible trade on a shed you can easily recover in a decade, but a poor one on anything you want to last, which is why it stays in the outbuilding niche.

Roll roofing versus shingles and membranes

It helps to see roll roofing against its alternatives. Compared with asphalt shingles, roll roofing is cheaper and faster to install and works on lower slopes where shingles cannot, but it lasts far less long and looks utilitarian rather than attractive, so shingles win for any steep roof or where appearance matters. Compared with a proper low slope membrane like TPO or EPDM, roll roofing is much cheaper and simpler but far shorter lived and less robust, so a membrane wins for any low slope roof you want to last or that protects something valuable.

The honest positioning is that roll roofing is the budget, short term, low slope option, ideal for sheds, porches and outbuildings where cost and simplicity are the priorities and a decade or so of service is fine. When you need appearance and long life on a steep roof, choose shingles; when you need durability on an important low slope roof, choose a membrane; when you need cheap and easy on a humble low slope outbuilding, roll roofing is exactly right. Matching the material to the job, as always in roofing, is what gives you the best result for your money.

The pros and cons of roll roofing

Seen this way, the decision is straightforward. If your project is a shed, garage or porch, cost matters, and you are comfortable with a roof you may redo in a decade, roll roofing’s advantages fit perfectly and its drawbacks barely matter. If your project is a home, or a low slope roof you want to last, the drawbacks disqualify it and a better material is worth the extra cost. Being honest about which situation you are in points clearly to the right choice.

Tips for a longer-lasting roll roof

You can push roll roofing toward the longer end of its lifespan with a few sensible choices. First, favor the concealed fastener and double coverage methods over single coverage with exposed nails where you can, since keeping the fasteners out of the weather and doubling the coverage both add years, in exchange for a bit more material and effort. Second, seal the laps and edges thoroughly with roofing cement, because the seams are where roll roofing most often fails, and a well bonded lap resists both wind and water far better than a loose one. Third, install it in mild weather when the material is pliable and bonds well, not in cold that makes it stiff and brittle.

Once it is on, a little maintenance goes a long way. Keep the roof clear of debris and standing water, since ponding is hard on any low slope roofing, and check the laps and edges periodically, resealing any that begin to lift before they turn into leaks. Because roll roofing is thin and its seams are its weak point, catching and resealing a lifting lap early is easy and cheap, while ignoring it lets water in. With good installation and this light attention, a roll roof will reliably serve out its intended life on your shed or outbuilding, doing its simple job at the low cost that makes it worthwhile.