Learn More About Hot Mop Roof


Hot Mop Roof

Hot mop roofs use a combination of felt and asphalt; this creates various layers which are then finished with a layer of gravel. A hot mop roof is only used on flat and low roofs, they are sometimes called tar and gravel roof. While the installation process can be a messy one, the price is exceptionally appealing to many homeowners.

Click to read our hot mop roof Q & A.

Hot Mop Roof Basics

The installation of a hot mop roof is a messy experience. Basically asphalt blocks are melted into a cauldron or bucket, once melted it is poured onto the roof and a team of installers will mop it into place. The heat of the asphalt can easily burn the installers, so additional care has to be taken during the installation process. Once the asphalt has been mopped into place a layer of felt and fiberglass is laid over it. Once the fiberglass and felt layer is completed, the roof gets another layer of melted asphalt, this is repeated a number of times. The roof is then topped with rock or gravel.

Hot Mop Roof Prices

Cost of Materials - $0.75 to $2.75 per square foot or $75 - $275 for each square.

Installation Cost - $2.00 to $4.00 per square foot or $200 - $400 for each square

Total Cost - $2.75 to $5.75 per square foot or $275 - $575 for each square.

Hot Mop Roof Advantages

Tear Off

The biggest advantage to a hot mop roof is that it can be installed over an existing roof without having to tear off the old roof. This can be highly cost effective, in many cases saving up to $2 per square foot.


A hot mop roof can be an affordable solution for a new roof. While this is not the longest lasting roofing material on the market, the cost can be exceptionally appealing to homeowners that have to replace their roof quickly. In some cases, this particular type of roofing material will require maintenance now and again.

Fast Installation

The hot mop roof is fast when it comes to installation. It can take up to two days to install an entire roof, based on the number of installers. This is good when you think an average clay tile roof can take up to ten days to install.

Unusual Roof Shapes

Roofs with unusual shapes will benefit from this type of roofing material. The melted asphalt is easy to apply simply to a variety of shapes. The fiberglass and felt can also be cut to the right size and shape with ease. Chimneys and air conditioning units are not an installer's nightmare when using this roofing material.


Life Span

A hot mop roof can last up to twenty years. This is exceptionally short when you look at the life span of other roofing materials. In most cases the hot mop roof will last anywhere between fifteen and thirty years. Regular maintenance is key to ensuring this type of roof lasts for as long as possible.

Hop Mop Question

I have a flat roof that was previously hot mopped. I want to remove the bad parts without completely replacing the roof. My question involves how to remove the rotten roof parts and specifically whether the mineral paper is glued to the wood below, nailed or is actually just stuck down. How with this typically work with a hot mop roof?

Steve - Homeowner

Site Editor's Reply

Steve, I don't think there's any specific answer to that question. You're gonna find out how they attach the underlying material when you rip up that first section of rotten roof. I would start with one section, find out how they applied the materials. It's going to totally depend on what the contractor or roofer did in that instance.

However, once you do understand the technique, then you can easily get a game plan together as far as how to handle the rest of the repair sections. Certainly from a cost perspective, replacing the rotten part is going to be easier than ripping up the whole roof and starting from scratch.

Bill - Site Editor

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