Tackling rooftop retrofit headaches

By Jesse Sanchez. 

Why pros are swapping out old-school plumbing vent workarounds for this purpose-built solution. 

For contractors tired of wrestling with mismatched pipe sizes and pricey custom parts during roof jobs, a small piece of plastic might be the biggest time-saver they didn’t know they needed. 

TUBOS, a specialized PVC insert designed for reroofing projects, is cutting through the confusion and cost of connecting modern plumbing vents to older cast iron systems. The product has gained traction not just for what it is, but for what it avoids. 

A quick look through TUBOS’ FAQ section reveals a clear pattern: professionals are frustrated with makeshift solutions. The most common question? Why not just use standard PVC couplings. The answer: they don’t fit. TUBOS states, “You cannot buy PVC couplings that will fit on a cast iron pipe (inside or out) that will convert to fit onto PVC.”  

Even no-hub couplings, the kind with hose clamps on each side, can create new problems. According to TUBOS, using those requires a larger lead boot, adds extra cost and forces installers to “squeeze all the extra lead into the smaller existing pipe.” Plus, there’s the added labor of sourcing and transporting multiple parts. Something TUBOS eliminates by shipping everything directly to the site. 

For those rooftops already using PVC vents, there are still some challenges. TUBOS explains that external couplings still require a larger, more expensive boot. And since cast iron vent stacks dominate older buildings, “90% of your reroof jobs will be cast iron.” 

While some have asked about stacking two differently sized PVC pipes and gluing them together, TUBOS explains, “The inside and outside diameter of TUBOS is one of a kind,” The measurements are intentionally engineered. The design lets the insert anchor into both cast iron and PVC, while the outer lip keeps it from slipping through the PVC stack. 

For roofers navigating various plumbing materials and modern requirements, TUBOS makes a case for being more than a product. It’s a calculated answer to a recurring jobsite problem. And for many, it might be the difference between a frustrating patch and a professional finish. 

Learn more about how TUBOS is helping contractors cut costs, save time and provide a solution to the cast iron to PVC connection problem for good!