News & Articles

Metal vs. Fabric Buildings

December 5, 2019
Cobra Structures sand storage
By: Robert Lee

While pressure washing a vehicle inside a Quonset fabric structure, I noticed that moisture was dripping from the curved roof, yet none of the spray was reaching higher than a few feet above the truck. It was cool outside, and I was using warm water. The vapour was rising, condensing on the upper reaches of the steel ribbing and falling like rain.

That was not the problem that I saw, however. What I saw was that the condensation that remained on the bolts and nut ends was evaporating, and over only a few years of this type of incident reoccurring, rust was evident everywhere. Yes, galvanized metal is supposed to be rust-resistant, and it largely is. However, at key stress points such as bolt holes, rust inevitably takes hold and soon those rust spots turn to holes, and leakage occurs, exacerbating the problem. This metal building leaked everywhere.

Metal Building Problems

Leakage is one of the problems common to older metal buildings. Cycles of heat and cold, sun, and wind and differences between the internal and external conditions lead to warping of the metal so that rivets pop or moisture accumulations lead to rust penetration at key points. Metal is a great conductor, too. Not only of electricity, making steel and aluminum buildings risky for a handyman to wire on his own, but of heat and cold, making them quite uncomfortable in which to work during extremes of temperature.

Once the wind gets hold of a loosened panel, it makes short work of the metal, stripping it from its moorings. One of the most common scenes in hurricane season is the flapping of aluminum panels on buildings, or sheets of the metal flying by like a kite in the air.

Metal is rigid. This limitation restricts the design of metal buildings and forces engineers to construct smaller spans than can be created with fabric buildings. The unwieldy configuration of metal buildings reduces options for expansion, development, and usage of the interiors. Cuts and bends form stress points or weakened spots in the material, making them prone to breakdown.

Manufacturers of steel clad, steel roofed or aluminum buildings claim that their buildings have lifespans exceeding 50 years, yet simple observation of older steel buildings across the rural landscape shows that many of these supposedly durable buildings already are falling into disrepair, after as little as 20 years. Why? Simply put, manufacturers’ claims of longevity apply to the thickest gauge, most expensive products. These buildings may well be out of the economic reach of most consumers.

Benefits of Fabric Buildings

On the other hand, fabric buildings, like metal ones, come with a wide range of material options. The most salient differences? The initial cost and replacement cost. You can replace fabric building skins as needed, repairing them quickly and easily. Yet, workes design even moderate- or budget-level fabric to last twenty years or more. With almost no maintenance, these stretched fabric buildings last a similar length to steel buildings but do so at a fraction of the cost.

Trusses and base plates of fabric buildings generally are coated and designed to last virtually forever, making them less likely to age like many of the swayback and buckling metal building counterparts. Because of the inherent tensile strength of fabric buildings, they resist wind, rain, and snow load easily, deflecting the elements while metal build design encourages blunt resistance against the wind, with roof lines often allowing snow to accumulate and compress roof infrastructure.

Poly-fabric, unlike metal, is resistant to rot, corrosion, and even the impact of chemicals and fuels. This makes these buildings much more suitable for use as machine shops, hazardous chemical storage buildings, and other high-risk uses. While steel and aluminum served their purpose decades ago, the new fabric, poly-fabric, or tension-fabric buildings would serve the majority of applications much better and much more economically. Even as a place where I can wash my truck without carrying an umbrella to protect against the falling raindrops from roof rivets.