How Long Does a Metal Shake Roof Last?

How long does an aluminum shake roof last?

An aluminum shake roof lasts as long as its weakest details allow, and the metal itself is rarely the limit. Aluminum does not rot, does not absorb water, and does not rust, so the main ways wood and many other materials wear out do not apply. We avoid quoting a single number of years, because the honest answer depends on installation quality, flashing, ventilation and exposure. What we can state is the written coverage. Interlock roofs carry the Guardian Lifetime Limited Material Warranty, which covers material and finish for the original purchaser while they own the home; it transfers once, and the second owner is covered to 50 years from substantial completion. Workmanship is excluded from that warranty. The coating is separately backed by a 30 Year Alunar® coating warranty.

Why do cedar shake roofs wear out sooner in New England?

Cedar shakes wear out sooner here mainly because they stay wet. Wood is durable when it can dry between storms, but many New England roofs sit under tall trees, face north, or hold snow for weeks. Damp wood grows moss, lichen and fungus, which hold more moisture against the surface. Freeze–thaw cycles then work on any water that soaked in, opening cracks and splits. Over time shakes cup, curl and lose thickness, and fasteners loosen as the wood around them softens. On the coast, from Cape Cod to Downeast Maine, fog and salt air add to the moisture load, though cedar itself tolerates salt better than bare steel. How long any given cedar roof lasts varies widely with the wood grade, the slope, the exposure and how often it has been cleaned and treated.

What maintenance does a metal shake roof need?

A metal shake roof needs very little maintenance compared with cedar. There is no treating, sealing or replacing split pieces, and moss does not root into a coated metal surface the way it does into wood. The sensible routine is a visual check from the ground each spring and after major storms, keeping gutters and valleys clear of leaves and pine needles, and trimming branches that rub or drop debris on the roof. Flashing at chimneys, skylights and walls deserves a look every few years, because sealants and masonry age even when the roofing does not. If you have a heavy salt exposure on the waterfront, rinsing deposits off sheltered lower sections where rain rarely reaches is a reasonable precaution. Avoid walking on the roof yourself; call us if something needs attention.

What can shorten the life of a metal shake roof?

Poor installation is the main thing that shortens the life of any metal roof. Incorrect fastening, rushed flashing at chimneys and walls, and badly detailed valleys cause most problems, not the panels. Attic ventilation matters too. A poorly vented attic traps warm, moist air that condenses under the deck in winter and can damage sheathing over time. The same heat loss drives ice dams, where meltwater refreezes at the eaves and backs up. No roof prevents ice dams by itself, and ice damming is excluded from the material warranty, so we review insulation and ventilation with you. Finally, mixing incompatible metals, such as certain fasteners or flashings against aluminum, can cause corrosion at the contact points. A trained Interlock crew uses compatible components throughout the system.

How does a metal shake roof handle nor'easters and heavy snow?

A metal shake roof handles nor'easters well because the panels interlock and are fastened to the deck, leaving no loose edges for wind to grab. Interlock roofs are rated for 120 mph wind when installed to manufacturer specification. Wind-driven rain is the other nor'easter hazard. Proper underlayment, ice barrier at the eaves and valleys, and well-detailed flashing keep water from working in where the roof meets walls and chimneys. For snow, the light weight of aluminum, roughly 0.4 to 0.7 lb per square foot, leaves more of the structure's capacity for heavy, wet snow. Snow may slide off more readily than from rough cedar, so snow guards over doors, walkways and lower roofs are worth discussing. That is especially true in the White Mountains, the Green Mountains and other ski country.

Is a metal shake roof worth it compared with replacing cedar?

For owners who plan to stay put, a metal shake roof usually makes sense because it ends the cycle of cedar maintenance and replacement. You keep a wood-shake look while removing rot, splitting and treatment from the list. The upfront cost is higher than some alternatives, and the roof has to be installed well to deliver its full life. When cedar is replaced, the old roof must be torn off first; Interlock is never installed over cedar. Our New England job book includes 15 Shake and 102 Cedar Shingle profile roofs, part of 5,036 Interlock roofs completed across the six states since 1999. If your home is in a historic district, check with your local historic district commission before changing from wood. An in-home consultation is the best way to see whether it fits your house.

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