On a sunny fall day in Joplin, Missouri, Ridgeline Roofing & Solar completed a commercial roof inspection at the Joplin Expo, located on the south side of Northpark Mall. The structure features a 60-mil TPO membrane, fully adhered over a tapered ISO insulation system and despite a few minor issues, the roof still has plenty of life left.

The Roofing System: Built for Drainage and Durability

This fully adhered TPO roofing system is installed over ISO board, with fastener plates anchoring the insulation to the structural B-deck. The system is also equipped with a tapered insulation design, which thickens and thins in certain areas to encourage proper water drainage.

“This roof is built smart. It funnels water in all the right directions and includes an overflow drain system as a backup—something every commercial roof should have,” said Tim Yates.

Even though the overall system is in great shape, Tim and the team uncovered a few concerns:

• Screws backing out of the termination bar, causing minor leaks
• Parapet coping damage from what appeared to be heavy rooftop equipment
• Small punctures in the TPO membrane, likely from rooftop crane equipment

Why Commercial Roofs Leak Far From the Damage

This inspection provided a great example of why commercial roof leaks can be deceiving. Water may enter the system at one end of the building but only become visible hundreds of feet away, traveling along the B-deck’s ribbed metal channels until it finds a vulnerable point.

Tim explained that while the leak source may seem localized, tracking the origin requires experience, patience, and a deep understanding of flat roof construction—especially when red iron and B-decking are involved.

Understanding R-Value in Flat Roofs

Thermal resistance was also discussed. The team estimated the current ISO thickness at approximately 2 inches, delivering an R-value of 12, with thicker areas providing up to R-36. This tapered design not only supports water drainage but improves energy efficiency where it matters most.

Final Assessment

Despite the minor punctures and fastening issues, the TPO membrane is in solid condition. With a few targeted repairs, the Joplin Expo’s roof will continue to perform effectively for years to come.

Managing a commercial property in Southwest Missouri? Let’s make sure your roof is ready for the seasons ahead. Contact us today!

Hear Tims’s Thoughts

Video Transcript: "Hey Tim Yates Ridgeline Roofing and Solar. I'm at the Joplin Expo right now at the North Park Mall
with Dave the Drill Sergeant. He's over there and we're just out here on this nice pretty sunny day
checking this roof out. So this is a 60 mil TPO. It's 12 foot rolls and it's all fully adhered
which means this whole all this TPO is glued down and it's glued down over ISO which is the
insulation board. You can see the plates and half the fasteners in this and we're just finding some
issues with it. So we found some holes in it and I think people bringing stuff up with this. This is
just like a little crane mounted to the top of the roof. They actually dropped it and something on it
damaged some stuff damaged the parapet a little bit the coping on it and there's a few issues we found
with the coping. It wasn't bad. This termination bar down here has got some screws coming out. You can
see that there and that's causing leaks in a couple of places but this building is built to funnel this
water in different directions and it's also also this ISO has a tapered system on it too. So this this ISO
is actually built prefab system to where it's thicker in places and thinner in places to trot that water as
well. So down this valley here you can see where the the water's been running down and running into
this drain here this roof drain and this drain here is an overflow for when that drain ever gets clogged up
and that's a great idea for for a commercial roof to have an overflow like that because every once in a
a while you hear of a story of a drain getting clogged up on a roof and something caving in and that's never good.
So this is a curb mounted access here and I wanted to show you guys down here what a b deck looks like. So this is all red iron and then you've got your b deck right here and this runs throughout the whole roof. So these are notorious for if you have a leak a mile away on a roof like this it might come all the way through here before it ever leaks. So the water will leak way down there.
never good. So this is a curb mounted access here and I wanted to show you guys down here what a B
deck looks like. So this is all red iron and then you've got your B deck right here and this runs
throughout the whole roof. So these are notorious for if you have a leak a mile away on a roof like
this it might come all the way through here before it ever leaks. So the water will leak way down
there because of this B deck and it'll run down this this little channel this little rib here all
the way down until it finds a way in and that's what makes commercial roofs like this so hard to
find leaks a lot of times because you might backtrack that for quite a while before you actually find it.
So we tried to figure out the r value here how thick it was it's only about two inches thick here
so this would have an r value of about 12 and in the thicker areas say if it gets up to
to you know six seven inches six inches would give you an r value about 36 and that's your thermal
resistance. So anyway got some hoods up here some big hoods they are wired off to keep birds from
flying in that's a good idea because those fans will sure shred them. Anyway if you have any questions
about your roof residential or commercial please give us a call thank you."