Walking on a roof can damage it, or worse, you may fall off and be injured or killed:

Here we describe roof safety and roof damage issues when inspecting, repairing, or otherwise walking on other roof materials such as asphalt, slate, wood roofs.

This article tells readers how to identify fragile or unsafe roof surfaces, when to stay off of them, how to repair them. By listing common causes of asphalt roof shingle failures and how to recognize them, building owners and roofing contractors may also be able to reduce the occurrence of asphalt roof shingle storage, handling, and installation errors that affect roof life

Roof shingle fragility and damage risks

Foot Traffic Damage to Roofs: Walking on some roofs causes damage as the photograph at the top of this page shows. That roof damage occurred when an inspector stepped on the fragile corner of an asphalt roof shingle. This pattern of breakage traced his footprints right up the roof to the chimney and back down the other side. These are the very "footprints of damage" which we have reported in some other articles on fragile, old, worn roof shingles.

[Click to enlarge any image]

This "failed" roof was not leaking until the fellow who was asked to inspect it walked across this fragile surface. From a ladder at the roof edge one could clearly see the virtual footprints of broken shingle edges where the "inspector" had walked. In this case the "inspector" was a roofing contractor who came back down to the ground and told the home owner that she needed a new roof right away.

She was upset because her ASHI-certified home inspector had said that the thought she could use the roof for another two to five years. Our opinion was that she did need a new roof very soon but that had not been the case until "bigfoot" had stomped all over it.

Worn out fragile roofs: The roof in the photograph shown here is one which is worn out, probably already leaking at least into the layers of roofing material, and it is so fragile that it should not be walked-on. I would stay off of worn, brittle, or cupped-shingle roofs, particularly in cold weather (shingles are more likely to break).

If we absolutely have to walk on such a roof, we would tiptoe carefully, avoiding stepping on the raised or cupped shingle sections, or if doing repairs, we would prop a ladder up off of the roof surface and work from that scaffold as is sometimes done with slate or other fragile roof surface repairs.

Guidelines for Direct Walking-On Inspection of Various Roof Surfaces & Roof Conditions

Some home inspectors reduce their workload and speed the the job by asserting that they do not walk on any roof surface under any condition, citing reasons of safety or fear of damaging the roof surface. But expert inspectors generally agree that there are many roof areas, conditions, and important roof defects, even total roof failure (such as thermal splitting), that are simply not visible except direct access to the roof edge (by ladder or other means) or by walking on the roof.

Watch out: Do not try to walk on any roof which is: too high, steep, wet, slippery, fragile, or covered with loose mineral granules, or other loose roof surface debris - such roofs are not suited for safe access. Do not walk on any roof which is installed over an incomplete, damaged, or rotted surface, as you might, like my helper on one roofing job, fall right through the roof surface!

Advice About Walking on & Inspecting Asphalt Shingle Roofs

We do not walk directly on any asphalt shingle roof that has one or more of these hazards:

• Roof is uncomfortable or feels unsafe or too fragile for any reason, in the opinion of the inspector
• Steep pitch roofs - judgment of the inspector
• High roofs - judgment of the inspector
• Fragile roofs - judgment of the inspector
• Wet, icy, snowy roofs - judgment of the inspector
• Roofs with curled, cracked, or broken shingles - judgment of the inspector
• Roofs for which there is not ready, safe access - judgment of the inspector

Loose mineral granules on an asphalt shingle or roll roofing roof surface, are dangerous and can cause the inspector to slip and fall off of the roof, regardless of the cause of loose material: whether because the roof is brand new (initial granule loss due to wear during installation) or old (mineral granules are loose because of age and loss of adhesion, weather exposure, or foot traffic).

Inspecting at ground level (photo above left) may show evidence of severe roof granule loss even before the inspector, owner, or roofing contractor has placed a ladder at the roof edge for a closer-look. From the roof edge you may see a gutter with a half inch or even more of mineral granules (above right). The two times we see asphalt roof shingle mineral granules on the ground or in gutters in quantity is at brand new asphalt shingle roofs, or at older, damaged, worn roofs whereon granules have lost their adhesion to the shingle by weather, age, foot traffic, hail, or other damage.

The determination of the safety and reasonableness of inspection method of any roof (or any other building component) is the sole responsibility of the building inspector, with the exception that the building owner also has the right to ask that the inspector omit or not access any building component or system.

The inspector is required in all cases to describe how an inspection was performed or if it was not performed, to explain why and to explain the implications of this to his or her client.

Advice About Inspecting & Walking on Cement Asbestos or Fiber Cement Roofs

Cement asbestos roof shingles: these shingles are as fragile as slate; it's best to stay off of this surface. Though we've walked carefully on a few such roofs it's easy to damage them. See our inspection advice at ASBESTOS & FIBER CEMENT ROOFING and our advice about tile and slate roof inspections found in this document (below).

Advice for Walking on & Inspecting Clay Tile Roofs

To prevent breakage, walk on tiles with extreme caution. Profile tile and lightweight tile are the most vulnerable, and concrete tiles are more fragile when they are freshly manufactured or “green.” If possible, place antennas and other roof-mounted equipment where it is easy to access without crossing many tiles.

When it is necessary to walk on tiles, step only on the head-lap (lower 3 inches) of each tile. With Mission- or S-tiles, it is best to step across two tiles at once to distribute the weight. When significant rooftop work is required, place plywood over the tile to distribute the load.

Watch out: our own experience is that it is absolutely impossible to walk on many clay tile roofs without damaging them, particularly soft clay such as the roof type used in Latin America (our photo at left).

For these roofs contractors have to remove sufficient clay tiles to provide a walking area. The removed tiles are replaced as the worker is leaving the work area of the roof.

Below we show two photos of a low slope (leaky) flat shingle-style clay tile roof on a New York Home. The ease of access meant that this roof was walked-on by someone (not us) who broke many clay tiles. You'll also notice the flattened metal tabs that were intended to hold replacement tiles in place. The tabs appear to have been bent flat by snow sliding down the roof, thus permitting clay tiles to begin to move as well (see the loose tile in the center of our photo at below left).

On some other fragile but not totally fragile roofs such as slate roofs, cement tile, cement-asbestos, fiber cement, and hard-fired ceramic clay tile roofs, contractors suspend a ladder over the roof surface, hanging it from the ridge, and cushioning it off of the roof surface using foam or insulation padding, or contractors work from scaffolding. - Ed.

Advice for Inspecting Other Fragile or Unsafe Roof Surfaces

• Cupped roof shingles: stay off in cold weather; inspect the shingles from the roof edge, from upper building windows, or if the roof must be walked-on, step carefully in the cupped portions on tiptoe, avoiding stepping on the raised curled portions of the shingles as otherwise you'll break off large corners and may lead to an immediate need for re-roofing. If the shingles are also brittle, even in warm weather, do not walk on the roof. See CUPPING ASPHALT SHINGLES


• Cracked roof shingles: vary in fragility, depending on shingle age and reason for cracking. Some "cracked" roof surfaces such as roofs damaged by thermal splitting, are not likely to be further damaged by careful direct inspection by walking their surfaces. See CRACKS & THERMAL SPLITTING in FIBERGLASS SHINGLES


• Curled roof shingles: as with cupped shingles, stay off in cold weather; inspect the shingles from the roof edge, from upper building windows, or if the roof must be walked-on, step carefully on the flat portions of the shingle, on tiptoe, avoiding stepping on the raised curled edges of the shingles as otherwise you'll break off the edges. If the shingles are also brittle, even in warm weather, do not walk on the roof. See CURLING ASPHALT SHINGLES


• Fishmouthed roof shingles: are fragile and may be damaged if you step on the raised portion of shingle. If the fishmouthing is on a fairly new roof and the shingles are not otherwise brittle it may be possible to walk on such a surface. See FISHMOUTHING ASPHALT SHINGLES


• Low-slope or single membrane roofs: can often be safely walked-on but beware of fragile, worn roll roofing which may be damaged by careless foot traffic, and beware of raised blisters, ridges, wrinkles which can also be damaged by careless walking.

Advice for Walking on or Inspecting Metal Roofs

Metal roof surfaces: can be walked-on provided

(1) the roof is not too steep and

(2) the metal roofing was installed over closely-spaced nailers or sheathing. Beware that some metal roofs may be installed directly over rafters and widely spaced horizontal nailers, and may be fragile or subject to denting.

Do not step on raised seams or other flashing areas that may be damaged; beware, metal roofs are very slippery when wet. The metal roof in the right-hand photo above was high, steep, and slippery. We would not consider walking on such a surface.

Advice About Walking on & Inspecting Slate Roofs

Slate roofs are fragile and are likely to be damaged by foot traffic; it's best to stay off of slate roof surfaces during a building inspection. See SLATE ROOF INSPECTION PROCEDURE for details.

Inspectors should be cautious in evaluating any roof condition to avoid failing the roof material itself when leaks are confined to flashing areas.

Watch out: our own experience is that it is absolutely impossible to walk directly on slate roofs without damaging them, particularly if the slates are worn, loose, damaged. And walking on such surfaces is unsafe.

On some other fragile but not totally fragile roofs such as slate roofs, cement tile, cement-asbestos, fiber cement, and hard-fired ceramic clay tile roofs, contractors suspend a ladder over the roof surface, hanging it from the ridge, and cushioning it off of the roof surface using foam or insulation padding, or contractors work from scaffolding.

Our photo (above left) shows a slate roof being replaced in Duluth, MN. Notice the pairs of ladders that are used to install new slates without walking on this roof surface. The ladders address both a steep slope falling hazard and the probable damage to the slates from foot traffic.

Advice for Walking on & Inspecting Wood shingle roofs:

Wood shingle or shake roofs such as shown in our photograph are fragile and will be damaged by any foot traffic.

We've walked on new, good-condition wood shingle roofs but they are easily damaged by foot traffic which can cause splits in the shingles. In addition wood shingles are often slippery and dangerous to walk on and absolutely slippery when wet.

Advice for Walking on or Inspecting Wet, Icy, Steep, Snow-Covered Roofs

Wet, icy, or snow covered roofs are unsafe to walk on in most circumstances, possibly excepting expert inspection of flat roofs with safe parapets or railings installed.

Also see Building Safety Hazards Guide, and readers are also invited contribute roof failure information to the web author for research purposes. web author for research purposes.

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• ALGAE, FUNGUS, LICHENS, MOSS on ROOFS - a really slippery roof surface
• ROOFING INSPECTION & REPAIR - home

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