Ask anyone who has a flat roof and they'll tell you: Flat roofs will leak. It's simply seen as inevitable. The tradeoff for adding the extra usable space on top of the roof is that water will be extremely slow to drain off the roof, leading to leaks. And, well, that's not entirely true. There are several ways a building-owner, particularly one with an older building, could go about having a metal roof restoration that should, at least, greatly minimize the chance of leaks. Whether they'll go away entirely largely depends on the quality of the job done. Here are some of the options.
For decades, the most common material used to make metal roofs was either terne (a tin/steel alloy) or copper. However, these tended to increasingly leak over time. Today, aluminum is almost universally used, and should offer a life of at least three decades with minimal leaking. However, replacing your entire metal roof with more metal is also extremely costly and disruptive.
Rubber is quickly becoming one of the most popular ways of sealing up a leaky metal roof. You've got two basic options here. There's EPDM, a sort of synthetic rubber which comes in rolls and is laid down almost like carpeting. It's quite inexpensive, but sealing the many seams is an issue. The other option is sprayed-on liquid rubber, which is a bit more labor-intensive, but -when applied properly- creates a seamless seal regardless of roof topography.
Modified bitumen is basically thin rolls of asphalt, applied to your roof. The rolls are bonded to the roof -and each other- through the use of intense heat, generally via blowtorch. It's labor-intensive and dangerous for non-experts, but the result is a highly weatherproof roof that also brings substantial long-term insulation and associated cost-savings.
A good middle ground in terms of cost and performance are elastomeric and/or acrylic roof coatings. These coatings are sprayed on to create a flexible membrane that covers the entire roof. You get weatherproofing and insulation benefits, without so much labor or disruption to your daily work.
At TRUCO Coatings, we have decades of experience restoring and protecting roofs of all shapes. Contact us for a consultation!