Resurfacing a Flat Roof

Scott: I own a house with a nice architectural shingle roof. Years ago, I added a lanai on the back and was recently told I should have something done to the flat lanai roof in order to prevent future leaks. I was told I have three options; and I don’t know if you’ll agree to these or not. I can have it tarred in; I can have it torched – if that’s what they call it. Or, I can have a coating applied that will waterproof it and also reduce the temperature underneath. What are your thoughts?

Jared: Yes, there are several different products you could use to resurface your flat roof. A method that you referenced is using the material called modified bitumen. It’s the most common material used on roofs here in Florida. It’s a rolled material; people call it torch down or modified, others call it rubber. But the real name is modified bitumen. It’s an asphalt base material where they add rubber or SPS modifiers to it so that it remains flexible - that’s going to be the most common. It can be installed multiple ways; with a torch where it’s actually melted down. It can be installed with a self-adhered method; it has a sticky wrapper on the back which when removed adheres it down. And there is the cold process method where you chemically fuse one piece of asphalt material to another. Also, there is the hot asphalt method using a big 400 degree kettle of asphalt. Modified bitumen is a common material here in Florida, but not my first preference.

The material that I would recommend is Hydro-Stop. It’s great for use on flat roofing materials. Its main advantage that when it’s finished there are no seams in it whatsoever; it is completely seamless. The other thing is that it is not made of asphalt; it doesn’t hold heat the way asphalt does. On a 90 degree day it’s going to be 92 or 94 degrees. Hydro-Stop is much cooler. Nine times out of ten, that is the material I would recommend for a flat roof here in Florida.

Also, with most flat roofing material, you have to completely tear it off and replace it every ten or fifteen years. With Hydro-stop, all you have to do is put what is called a maintenance coat on it every ten or fifteen years and then you get a brand new warranty.  It’s the best type of material out there for flat roofs in my opinion.

Scott: They’ll just roll that on it? Is that right?

Jared: It’s actually fluid-applied. We make it on site to the exact dimensions of the roof. First a layer of foundation is applied, then a polyester cloth. And then there’s another layer of foundation coat and then two layers of what is called toppers Premium Coat. It’s basically a roofing system that is made on site - instead of a manufacturing plant – to the exact dimensions of your roof.

Scott: My roof is eight to nine squares; what would something like that cost?

Jared: Approximately $3,600 is what I would estimate.

Scott: Okay, I appreciate the info.

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