While walking on any roof surface should be kept to a minimum, occasionally it may be necessary. Caution should be exercised since most manufacturers specifically do not warrant breakage due to foot traffic. If tiles are broken, they should be replaced as soon as possible to avoid damage to the underlayment from water intrusion or exposure to the ultraviolet rays of the sun.
Walking on any roofing surface should be done with extreme caution. Steep slopes, slippery surfaces, vents, antennas, solar panels, chimneys or any other object on a roof can increase the hazards of falling from a roof. The TRI recommends that you utilize a trained roofing professional for accessing your roof.OSHA has created mandatory “fall protection” guidelines that assist in preventing serious accidents.
To avoid breaking tiles, there are certain methods of traversing that may minimize damage. Typically, it is recommended to step at the bottom three inches of the installed tile. This is the portion of the tile that is supported by the lapped tile beneath it and the weight is transferred through it to the deck below. Orient your feet in a direction parallel with the ridge and try to distribute your weight evenly and walk as softly as possible. On high profiled ‘S’ tiles, it is recommended to distribute your weight with the heel and toe on the high points of adjacent tiles.
It is also recommended to stay away from hips or valleys to avoid breaking cut tiles that would be more difficult to replace. The exception to this would be in situations where the hips and ridges are bedded in mortar or foam, in which case, they may be preferred walking paths. Valleys may also be access paths if the tiles are cut away from the center of the valley wide enough to allow foot traffic on the metal valley flashing.
Place antennas, solar panels and roof mounted equipment to minimize roof traffic for long term servicing and maintenance. When painting or repairing adjoining walls or other items, safely cover the tile surface with secured plywood sheets to distribute traffic loads and prevent dirt, building materials, and paint or stain from damaging or discoloring the tile.
See the proper article here Walking on tile roofs