Why Prioritize Prep Work Before a Roof Coating

By Western Colloid. 

Learn why prep work is so important when it comes to coating installations and what kind of prep work is needed most. 

If you want to be truly efficient when installing your next commercial roofing project, it’s important to always prioritize prep work. What do we mean by prep work? Generally speaking, this is preparing the roof for a new installation. It’s also the least fun part of any project. That’s why it is often our tendency to try and save time on this step because we want to apply product on the roof as soon as possible.  

However, this mindset can actually hurt the overall timeline of a roof coating installation job. When you don’t spend time doing prep work, such as covering equipment or masking off parapet walls, you could be adding on an extra day or two of labor to catch up and do these necessary tasks. Although the building owner may come around and wonder why no roofing has been installed during the prep work phase, just tell them the value of one day of prep saves two days of labor. 

We asked Chris Ford from the technical and training services division at Western Colloid about the need for roof preparation before installing a roof coating. He said: 

“In my travels, working with contractors all over the country, failure to perform proper prep work is one of the costliest missteps I see on a regular basis. When the crew is in a rhythm applying a roof system, they can generally cover a lot of ground in a short period of time. When they get derailed because another job pops up along the way it takes them a long time to get that rhythm back.  

It’s like a freight train that has to come to a stop, it doesn’t get rolling again at top speed until way down the track. When we transition from one task to another there is always time lost. Having to stop the roof application because an area needs to be cleaned, or needs to be covered to protect it, doesn’t just cost the time it takes to do that work. It costs you that times four because the other guys on the crew are likely just standing around while that one guy gets done with what he’s doing. 

Very few jobs on the roof require all members to be in the same location like fluid applied applications. When you stop them it’s not likely they will all find another task right away to keep them busy for 15 minutes, it’s more likely they will just stand around until it’s time to start spraying again. A 15-minute, one man job costs the company an entire man hour when you factor in the three guys not working.”   

An often-overlooked task is preparing pipes, conduit and wires laying right on the roof. You may be inclined to spray coating right over it, but someday those pipes and wires will need to be disturbed and then you will have damaged the seal of the roof coating. Lift up those pipes beforehand and then all you have to repair is a small area under your temporary riser.  

It’s very important to think about the air conditioners.  “If units need to be lifted and cleaned underneath, it is probably two to three times more efficient to get that done before starting the roof application,” Ford states. “I see crews leave those all the time. Then when they finally get around to addressing them there is much more dirt and debris under them than they thought. All that ends up flying around the roof and you battle it the rest of the job.”  

Don’t scrimp on the surface cleaning. A clean surface is needed for good adhesion. If this part of the preparation is not done right, the coating will be applied to the dirt instead of the surface, resulting in an uneven surface that might peel or blister. Power washing is aways preferred with a good scrubbing using a product like our Western Colloid’s #9000 Roof Wash & Prime – 9000. Note: you may have to catch or divert the wash water so it does not flow into public streets or waterways. 

Primer may be necessary for preparing a roof for a new coating. Your manufacturer should tell you if the roof surface you are trying to cover needs this additional step. Since commercial roofs are made of different materials, a primer suited for the applicable surface will work best for greater adhesion.   

It is also important to address rust when prepping a roof. If you have areas of rust on the roof you’re working on, a rust-inhibiting primer must be used. Our #900R MTL + Rust Primer-900R offers rust-inhibiting qualities as well as anti-corrosion protection. 

Another important step to follow is scraping and resealing around scuppers and drains and replacing these components if necessary. Following this best practice makes sure the water leaves the roof like it should. 

Here’s a general prep work checklist for you to follow: 

• Inspect the roof 

• Clean the surface 

• Mask off and protect 

• Lift items off the roof surface  

• Clean and prep scuppers and drains 

• Prime if necessary 

Once the proper prep work is done, now you can have fun roofing! 

Learn more about Western Colloid in their RoofersCoffeeShop® Directory or visit westerncolloid.com.