How do you install a built up roof?

built up roofing

What does built up roof mean?

A commercial or industrial structure will typically have a flat built up roof as opposed to most homes have a pitched roof. Why? There are two main reasons that a flat built up roof makes more sense for large structure, with the first being cost effectiveness. Built up roof construction for a large structure is less expensive than a sloped roof would cost. 

The second reason for a commercial structure having a flat built up roof is real estate. With large equipment like the HVAC system on the roof, it leaves space for parking, an essential need for a business. 

Built up roofing is a technique to roof a commercial or industrial structure’s flat roof.  Built up roof consists of layers called bitumen. Typically hot asphalt layered with piles of other materials alternated. Then a last layer of a built up roof with gravel. The multiple layers are installed ensure all the layers are adhered to the bottom layer with the final results creating the built up roof. 

How much does built up roofing weight?

Typically, a built-up roof includes the built-up membrane itself, cover board, insulation, and with or without gravel. Because they are layered, “built up”, not every flat roof will be the same thickness. This is one factor that makes is popular, the owner can choose the number of layers to be installed. Weights for 3-play and 4-ply built up roofs are as follows: 

  • Three Ply Built-up Roof with Gravel-Surfaced
  • Six pounds per square foot
  • Three Ply Built-up Roof with Smooth Surface
  • 2.33 pounds per square foot 
  • Four Ply Built-up Roof with Gravel Surface
    6.3 pounds per square foot
  • Four Ply Built-up Roof with Smooth Surface

2.58 pounds per square foot

How do you repair a built up roof?

Built-up roofs are durable, a key factor why commercial structure owners choose to go with that type of roofing. However, leaks will happen, even with the best maintenance and upkeep. Most of those leaks happen at the flashing where roof planes and protrusions are located.

 Leaks also develop when the top layer of gravel is blown off in high winds or an older roof simply wears from constant UV rays daily creates blister where leaks can start. Fortunately, most built-up roof leaks are easily repaired using the following steps: 

  • One: Clear the blister and areas of dirt and gravel. 
  • Two: Slice the top layer with a utility knife carefully to release any pressure inside the blister. 
  • Three: If there is moisture in the bubble, check along the flashing for other leaks and repair as needed. 
  • Four: Using a putty knife spread and work plastic roofing cement in and around the pocket. The roof cement should be spread out around the area of the blister in a 2-inch diameter. 
  • Five: Make a patch from rolled roofing 2-inches larger than the area you’ve repaired. Press and spread roofing cement over and around the patch.
  • Six: After the patch has completely dried, cover with gravel. 

What is the difference between built up roofing and modified bitumen?

Modified bitumen roofing has become a conventional alternative to built-up roofing, both consisting of asphalt and other materials like plastic or rubber polymers. Modified bitumen has the same redundancy as built up roof system, including the flexibility and UV resistance. 

The difference with the modified bitumen membrane, a hybrid type of roofing, combines high-technology formula and prefabrication of single-ply with the traditional roofing technique of built up roofing. These membranes used are factory-fabrication of asphalt layers modified with the plastic or rubber reinforcing material. 

flat black roof

Built Up Roof Pros and Cons: 

There are several factors and qualities that makes built up roof system the popular choice for commercial and industrial buildings. For example:

Built-up roofing and waterproofing is created by the multiple layers of bitumen and saturated felts, providing a structure years of protection from the weather. 

  • Built up roof systems are inexpensive with standard specifications.
  • Built up roof systems have exceptional heat resistance and heat conduction between a building’s exterior and interior, lowering energy bills. 
  • Built up roof systems have the best ROI with a lifespan up to forty years. 
  • Built up roof system is made of fiberglass and polyester reinforcement making it tear-resistant. 
  • Built up roof system is impact resistant.
  • Built up roof system is flexible and holds it shape with the temperature changes.

With all the factors we’ve discussed in this article, it is understandable why more owners of commercial and industrial structures are choosing a built up roof for their roofing system. The benefits are multiple, and the best one is not having to replace the roof again for years, a cost factor that any business can appreciate. Call 877-406-7663 today for your built up roofing installation in New Orleans, LA.

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