Failing ridge cap shingles (C) D Friedman G StewartRidge & Hip Cap Shingles
Installation, inspection, & failure diagnosis at roof ridges & hips

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Ridge & hip roof cap shingles: this article describes the installation of ridge and hip cap shingles and discusses the probable causes of early failures on ridge and hip shingles on asphalt shingle roofs when they fail in advance of other roof areas. The most common failure at the ridge or hip covering of most roofs, regardless of roofing material, is wind damage and blow-offs due to inadequate nailing. But on occasion, such as in our photo above, we see remarkable wear in the form of granule loss, cupping, or curling at the ridge that has not appeared elsewhere on the roof. Here we discuss why this wear happens and what to do about it.

This roof failure diagnosis article series investigates types and causes of premature or early roof wear or failures. We describe shingle granule loss shingle curling as a sign of wear on asphalt shingle roofs and discusses how to identify & explain the most-common asphalt roof shingle failures. Our page top photo shows shingle edge down-curling. Other photos on this page show shingle corner curling.

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Diagnosis, Cause & Repair for Early Wear / Failures at the Ridge Cap Shingles

Failing ridge cap shingles (C) D Friedman G Stewart

Our page top photograph shows ridge cap shingles that have worn out and actually lost shingle portions that have washed off of the roof. While this is an old, worn-out roof (on an entry to the Kingston NY library), it may be meaningful that at end of life the ridge cap shingles failed in the pattern seen there: bending stress over the ridge may have ultimately stressed the ridge cap shingles so that they broke at the ridge apex.

[Click to enlarge any image]

At left is a different and interesting ridge cap shingle failure that needed some thoughtful analysis.

Question: Why are these ridge cap shingles failing before the rest of the roof in this photo?

See the ridge cap shingle wear photo at left [click to see an enlarged, detailed version]. I’d like to understand why the ridge shingles only, deteriorated.

I was told that this was a Presidential composition asphalt shingle roof about 10 years old.

Do you know any roofers that have seen this condition? Thanks, Glenn Stewart, a.k.a. The House Whisperer

Reply: These Ridge Cap Shingles are from a different shingle model, batch, and possibly brand than the singles used on the body of the roof

A competent onsite inspection by a roofing expert usually finds additional clues that help accurately diagnose a roof or other building problem. But sometimes even experienced roofers and home inspectors as well as home owners can be left baffled by roofing failure patterns.

Nevertheless I am convinced that if we could know enough (or maybe know everything) about any given roof failure condition we would never ascribe the failure to random chance and we could indeed explain what's going on.

In this case we can make a pretty reasonable guess at why your ridge cap shingles look so different, and so worn, compared with the shingles on the main body or field of the roof.

First let's look at the shingles on the body of the roof

The pattern and style of shingles used on the main body or field of the roof in your photos look somewhat but NOT exactly like a laminate-type shingle or at least a style that mimics laminate type shingles. (We'd have to see a closer or edge view of the body shingles to know if they are actually laminated multi-layered shingle tabs or a single thickness design).

From the name you offered and the appearance, these may resemble but in your photo do not appear to be exactly like the Presidential Shake™ triple laminate shingles produced and sold by CertainTeed (Saint-Globan), a major roofing manufacturer. So I'm not sure if the roof shown (above left) is Presidential Shake™ triple laminate shingles or rather a lookalike.

Now let's look at the shingles at the ridge - the ridge cap shingles

But in any case, unlike a conventional three-tab asphalt roof shingle, the style and pattern of shingles on the roof body do not provide a shingle that would be easily cut up in the field to produce the rectangular individual shingles needed to cover a ridge or form a ridge cap at the apex of the roof.

That tells me that the ridge cap shingles are most likely not the same product or material as the shingles used on the roof body.

So we wouldn't be stunned if the performance of the ridge shingles differed from those on the field or body of the roof.

But what is unusual is to see ridge cap shingle failure so much earlier than wear on the field of the roof. I can guess at several explanations:

These ridge cap shingles may not be the same material, batch, and model as the field shingles on the rest of the roof and they may have been stored improperly

The roofer would have either bought special ridge cap shingles or more commonly the roofer would make the needed ridge cap covering by trimming and cutting asphalt shingles from whatever was at hand, sometimes even a different batch of conventional 3-tab roofing shingles. If s/he used whatever was at hand that seemed close in color to the field of the roof, it's plausible that a less costly (and less durable) model of roof shingle was selected to make the ridge cap.

A close look at your ridge cap shingle photo suggests that even the cap shingles may have been cut from laminated shingle material. I think I see multiple shingle edges in view.

On occasion too I've found roofers taking the expedient course of "using up" leftover shingles from a previous job to make the ridge caps. Depending on how old these leftovers were, and more importantly, where and under what conditions they were stored, they might well fail quickly when installed on a roof. Believe it or not, asphalt shingles not yet installed on a roof should be stored in a cool, dry place, out of direct sunlight. You can read this advice on shingle packaging and in installation manuals.

In sum, it looks to me as if the ridge cap shingles may have been a different, and inferior product to the shingles used on the rest of the roof. And worse, they may also have been stored or handled improperly.

While we could observe that there also seems to be no ridge vent on this roof, and while heat, moisture from below, and lack of adequate ventilation are important factors in shingle wear, curling, and even granule loss, the product difference and possibly product storage and age conditions are the most likely explanation of their early failure.

How to Distinguish Among Ridge/Hip Cap Shingle Failure due to Cracking, Excessive Bending, Poor Nailing, Thermal Splitting, Wind Damage, or Other Wear

Glenn added about the premature ridge cap shingle failure photo shown above that a roofer suggested that this shingle failure at the ridge was due to cracks where the shingles were bent over the ridge, and more serious because the ridge cap shingles were laminates, thicker, more likely to crack when bent.

Certainly bending shingles, particularly cold shingles, over a steep slope ridge can stress and break the shingles. I [DF] was taught to leave my ridge cap shingles indoors on a radiator in cold weather, assuring thus that they would be warm and flexible enough to bend without cracking when brought outside to nail onto the ridge or hip of the roof.

But shingle cracking failure does not physically resemble the cupping and granule loss failure in the photo shown at page top. Cracking shingles show just that - cracks. Indeed once the shingle has cracked the shingle substrate absorbs increasing amounts of water and in a freezing climate the freeze-thaw cycle will accelerate wear of the shingle.

There are several types of shingle cracking that occur: defective product or thermal splitting (CRACKS in FIBERGLASS SHINGLES), cracks due to cold or excessive bending at a hip or ridge, cracks due to excessive roof or structural movement, and cracking that appears as part of normal asphalt shingle wearing and age.

But in premature shingle failure conditions, that is, not normal aging, once cracking has occurred, the shingle wear is non-uniform, appearing first more severely around the cracks. The page top photo shows uniform cupping and swelling of the shingle material - a different problem.

Finally, when asphalt shingles crack due to being bent too acutely over a ridge, or being bent in cold weather, the crack that appears runs parallel to the ridge line - a pattern also not visible in the shingle failure shown at the start of this article.

Concluding OPINION about the ridge cap shingle failure photo shown at the start of this article

We agree that often cracks at the ridge cap shingles lead to their wear, more so if the shingle was thick and hard to bend, and still more so if the shingle was bent in cold weather or under cold conditions rather than allowing it to heat up first. And Certainteed as well as other roofing shingle manufactures warn about proper bending (with heat) to avoid cracked ridge cap shingles and rake edge shingles.

But in the case of the bald, curling ridge cap shingles above, the wear is not showing up as a shingle crack failure as much as curling and granule loss that extends across the entire cap, on both sides, and along all of the shingles along the ridge.

On roofs I installed or later inspected, cracking due to bending tends to be inconsistent - not the same on all cap shingles. And because water penetrates at the crack in the shingle, wear at a shingle crack tends to originate at and spread out from the crack.

The roofer may be correct, but to me, these shingles just don't look like a cracking failure. We don't see wear that originates at and is worse at the apex of the shingles where cracks would appear. In fact the worst granule loss is at the edges of the cap shingles, consistent with a shingle curling and granule loss failure not a cracking failure.

We have contacted Certainteed to ask the company's opinion and advice and will keep readers informed in this spot.

Ridge Cap Shingle Installation Details from Certainteed™

Ridge cap installation details - Certainteed InstructionsYou will read our own concluding opinion and reasoning about the cap shingle failure photo [above] at the end of the following comments and ridge cap shingle installation details provided courtesy of Certainteed.

Indeed, Certainteed warns in the installation instructions for these shingles:

CAUTION: To prevent cracking, shingles must be warm enough to allow proper forming for hips, ridges and valleys.

and the company also illustrates how ridge cap shingles should be installed (illustration shown at left, click to enlarge) and recommends:

For capping hip and ridge, apply CertainTeed “Presidential Accessory” shingles or Mountain Ridge shingles of a like color.

Cedar Crest or Mountain Ridge accessory shingles can be used for covering hips and ridges. Apply shingles up to the ridge. Fasten each accessory with two fasteners. The fasteners must be 13⁄4" long or longer, so they penetrate either 3⁄4" into the deck or completely through the deck.

Use Mountain Ridge accessory shingles to cover hips, ridges or rake edges. One box will cover 20 linear feet. To prevent damage to shingles during application, they must be sufficiently warm to allow proper forming.
FASTENING - IMPORTANT: Use two nails to fasten each shingle. Nails must be minimum 13⁄4" (45 mm) long. For the 4" (100 mm) starter shingle, place fastener 1" (25 mm) in from each side edge and about 2" (50 mm) from the rake (or eave) edge, making sure the fastener goes 3⁄4" into the deck or all the way through. For each full accessory shingle, place fasteners 85⁄8" (219 mm) up from its exposed butt edge and 1" (25 mm) in from each side edge.

Here’s a Tip… To provide a level surface for hip and ridge caps applied over Presidential TL, a “nailer” made from 1-by boards can be installed or a piece of metal can be formed to support the caps. Also ridge vents made from sturdy material
can serve as a base to provide an even uniform appearance.

Note that the ridge cap shingles in the Certainteed illustration are not a laminate of material. Also note that in the ridge cap failure photo above there is no roof ventilation visible. The company provides plenty of detail about installing hip and ridge shingles, as we continue to quote:

HIP, RIDGE AND RAKE SHINGLE APPLICATION [quoted Certainteed™ text is in italics below]

Certainteed ridge cap shingle installation details

Apply the primary field roofing up to the hip or ridge from both sides of the roof and trim flush or lap over one side, not more than half the width of an accessory shingle.

Assure that the installed accessory shingles properly cover field shingles on both sides and along rake edges. For a rake edge installation, cut the field shingles flush to the rake edge. Apply accessory shingles ensuring they fit securely against the rake board.

To assist in proper alignment, snap a chalk line parallel to the hip, ridge or rake along the line where the side edges of the accessory shingles should fall.

Prepare a 4" Starter shingle by cutting off the lower 8" color granule butt portion of one accessory shingle.

Apply the 4" starter piece (with sealant nearest the outer edge) over the bottom corner of the hip or rake, or on either end of the ridge, overhanging the corner or end by approximately 1⁄2" and bending the starter shingle along its centerline to form into place (see figures below.) Install a nail on each side about 2" up from the starter shingle’s exposed butt edge and 1" in from each side edge of the shingle.

The 8" piece that was cut off may be used to finish the opposite end of hip, ridge or rake.

Next, apply a full Mountain Ridge shingle over the installed starter shingle, bending it along its centerline and forming into place over the hip, ridge or rake, flush with the bottom and side edges of the starter shingle. Install a nail on each side of the shingle 85⁄8" up from the bottom edge and 1" in from each side edge. Continue application of the Mountain Ridge shingles along the hip, ridge or rake as shown. Expose Mountain Ridge shingles 8", covering all fasteners.


Cedar Crest hip and ridge shingles deliver a thicker appearance to accentuate the roof lines for a more attractive finish. Unlike other accessory products which have a monotone appearance, Cedar Crest has blended colors that complement the Landmark™ Landmark TL™, Presidential™ and Presidential TL™ shingle colors.

Cedar Crest’s multi layer design gives additional protection at critical stress points and its aggressive sealant helps ensure the caps stay on the roof. Use Cedar Crest accessory shingles to cover hips and ridges.

Carefully separate the three-piece units prior to application, by first folding along the pre-cut lines and then detaching the pieces (see Fig. 15- 19). No cutting is necessary. There are 30 individual shingles (10 three-piece units) in each bundle. One bundle will cover 20 linear feet

. Each 12" x 12" shingle has a shadow line that is a design feature which is visible when applied properly. To prevent shingle damage during application, they must be sufficiently warm to allow proper forming.

How to Nail the Ridge Cap Shingles - Ridge or Hip Cap Nailing Defects

Certainteed ridge cap shingle nailing details Shingle bending over ridge discontinuity (C)

At above left CertainTeed illustrates how to nail shingles at the ridge or hip. At above right our photo shows a ridge cap shingle being asked to serve beyond the call of duty. The home inspector's arrow marked an exposed nail where he advised his client to seal exposed nails on the roof at the ridge. In fact the chances of leaks at a nail at the ridge, the highest point on this roof, are less than chances that the ridge cap shingle, bent over a change in roof height, is going to crack, break, and leak or blow off of the roof as it ages.

[quoted text is in italics below]

IMPORTANT: Use TWO nails to fasten each shingle. Fasteners must be minimum 1-3/4" (45 mm) long. For the starter shingle, place fastener 1" in from each side edge and about 2" up from the starter shingle’s exposed butt edge, making sure fastener goes 3/4" into the deck or all the way through the deck. (see 15-20).

For each full Cedar Crest shingle, place fasteners 8-5/8" up from its exposed butt edge and 1" in from each side edge (see 15-21).

Ridge & Hip Cap Shingle Nailing Defects, Shingle Fall-Off, Leaks

We might expect cracking failures on ridge cap shingles bent over a very steep roof slope such as shown above. But when you see a cap shingle hinged and falling as shown in the center of this ridge (below left), I suspect that nailing was also inadequate. So we may have a double fault: the shingle cracked at the apex of the ridge, and the shingle fell because of minimal nailing.

Ridge cap fall off on steep roof (C) Daniel Friedman Hip cap shingles on a low slope roof (C) Daniel Friedman

At above right the hip cap shingles have an easy time - on this very low slope hipped roof they are nearly flat - so I don't expect a hip cap shingle cracking problem to occur. And the shingles were well nailed - at least none have blown or fallen off of this roof.

But what about installing conventional 3-tab shingles on a very low slope roof, less than 4 in 12? Unless there were hidden precautions such as a continuous ice and water shield barrier below these shingles I expect this roof to have a short, leaky life. As we explain at LOW SLOPE ROOFING , Asphalt shingles can be installed on roof slopes of 2:12 to 4:12 if special procedures are followed for underlayment ( ROOFING UNDERLAYMENT BEST PRACTICES). Details about how roof slope is measured or calculated are at ROOF SLOPE DEFINITIONS.

Examples of Ridge Cap Shingle Nailing Defects & Wind Damage

Ridge cap shingle wind damage (C) Daniel Friedman Ridge cap shingle blow off (C) Daniel Friedman

Above we see two different types of ridge cap shingle wind damage. At left Ithink the ridge caps blew off completely, and in intact pieces, because of inadequate nailing. Possibly the number of nails was too few, their position incorrect, or the roofing nails may not have been long enough to penetrate through the layers of roofing material and into the roof sheathing to the required depth (the tip of the shingle nail should penetrate to the other side of 1/2" plywood sheathing). A closer look at the shingle nails and nail pattern can answer this question during an on-roof inspection.

At above right we see a different shingle wind damage at the ridge. Here the ridge cap shingles were well nailed - as the nailed pieces remain in place. But strong wind got below and tore off substantial portions of the ridge caps. Why?

I can pose these possible explanations. The open-end of the ridge caps may have been facing into rather than away from the prevailing or most likely storm direction. Or the cap shingle overlapped ends may not have been adequately sealed to the shingle below. In addition to adequate nailing with properly placed and sized roofing nails, in high wind areas the roofer may want to add a daub of sealant at the open end of each cap shingle on the hip or ridge.

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