203 858 0080 naas@mac.com

Commercial Flat Roof Drains: Installation Position is Critical

Drains are an essential part of any commercial flat roof; however, it is critical to position them at the lowest point of a roof. When not appropriately placed, water will pool, causing load-bearing stress on the structure and the rubber membrane, which leads to leaks. Pooling water tends to separate seams around skylights, vents, a/c units, etc.

The video below demonstrates how to replace a drain on a commercial flat roof.

Types of Drainage Systems

Factors to Consider

  • The roof should slope toward the drain.
  • Drain and pipe must be significant enough for any volume of water.
  • A drain strainer must be designed to allow small debris and water to flow freely to the drain.
  • The placement of the drain, to other rooftop units, should be carefully determined.
Drain positioned at low part of roof but nor recessed therefor collecting debris

Inner Drains –

Although drains are on a flat roof’s surface, the inner drain pipes exist on the inside of the building, and below the ground surface leading to a drainage system. This prevents the pipes from freezing during the extreme temperatures of winter.

Scuppers –

Scuppers are openings in parapet walls, of commercial flat roofs, from which water can drain. These are very effective since water will flow freely through them, to a dedicated controlled area.

Outer Drains –

Outer drains begin on a commercial flat roof surface that is attached to drain pipes, which lead down the outer wall of a building, to the ground surface. During extreme winter weather conditions, water in these leader pipes, can freeze and crack the pipes.

Gutters – 

Gutters are a type of drainage system that is used to divert water from a roof and away from a building’s walls and foundation. In extreme winter weather conditions, water tends to freeze causing a build-up of ice, in the troughs, which prevents drainage.

Flat Roof Drain Basin – Video

A basin is a lowered area, recessed into a flat roof’s substrate, where water converges and drains, even when there is an accumulation of debris.

Commercial flat roof drain installation - This is an old cast iron drain and strainer. The strainer's holes and slots are too small, which caused small debris to build up and block water flow.

When Drain Basins are Needed

The images show drains that are correctly at the lowest part of the roof. The problem is, however, that an accumulation of debris is preventing water from draining. If these roofs had drain basins, water could have flowed over the debris.

This flat roof slopes toward the center of the roof where the drain is, however, the installation of a basin would have prevented ponding water and the growth of plant life.

Although the drain is properly located, a drain basin is needed.
This drain have been blocked for a long time and plants started to grow.

When the Location, Basin, and Strainer Work Together… 

…this image shows an example of a drain that functions as a proper drainage system on a commercial flat roof.

When the Location, Basin, and Strainer Work Together... results in an effective drainage system.

A Cast Iron Basin Drain from the 1930s

This cast iron drain and strainer is from the 1930s. Notice the small “basin” around the strainer. This basin was a good idea, but could not handle the amount of debris accumulation, and the strainer holes and slots were too small and narrow.

A Cast Iron Basin Drain from the 1930s - basin is too small and the strainer holes and slots are too small an narrow.

Which Drain for a flat roof is best? watch Video

Which Drain to use for a flat roof
There are three types of draining systems found for flat roofs Watch the other articles on drains and scuppers When installing a new roof, it is important to re-design the drains so they would function better. Although drains are the most ...
See Articles

Roof Drains

Flat roof - lower edge to drain water off
Roof Drains Roof Drains are one of the most problematic areas on a roof. The positioning, design, and installation of a drainage system are one of the most important factors to have a relatively low maintenance roof. The average flat roof does ...
See Articles

Copper Drain-Making a drain for a flat roof. Avoid Plastic drains

Making a Copper Drain
Plastic Drains are not fit for a roof How to make a copper drain. When you see a plastic drain on a roof, you need to consider replacing it. Plastic and rubber roofs don’t go well together. Best practices for ...
See Articles

Scupper on Flat Roof Repairs – Effective Drain – Westport

Flat Roof Scupper - Westport. Lower the edge of a roof to remove water from a flat roof.
Scuppers are effective drainage systems - Check out our Drain section of roof drains Scuppers are the most efficient means of removing water from flat roofs - living in Fairfield County, Westport, Greenwich, and Stamford, we get our fair share ...
See Articles

Scuppers – Flat Roof Repair

Scuppers - Flat Roof Repair
Scuppers for flat roofs Scuppers flat roof repair - The cause of a major leak was due to incorrect leader headers on the other side of the wall. Scuppers are perfect for getting water off a roof, but if water ...
See Articles

Flat Roof Pooling Water – Video on installing channel to remove standing water

Standing water on a flat roof
Pooling water on a Flat Roof When you have a flat roof water pool for extended periods of time, it could have negative results to the membrane and structure. These areas that pool also accumulates dirt and leaves that accelerate ...
See Articles

Drains, Scuppers and Gutters – the pro’s and cons

Flat Roof Drain System - Flat Roof Repairs - Massachusetts
The pro's and cons of DrainsScuppers and Gutters. Drains Cons
  • Debris collects through the strainer and blocks the flow of water very easily.
  • Unclogging a blocked drain needs professional people to do it.- costly
  • The roof needs to be cleared of ...
    See Articles

Scuppers – A Flat Roof Drain System for Commercial Roofs – Watch video

Flat roof - lower edge to drain water off
What is a Scupper? Scuppers are drain openings, placed through walls, that drain heavy water flow and debris away from commercial flat roofs. Installing a Scupper on an EPDM Flat Roof Watch the video below.  We are cutting away the edge ...
See Articles

Gutters on Flat Roofs – Important Drainage Systems

Gutter for flat roofs
Flat Roof Debris and Gutter Drainage Flat roofs collect an abundance of debris that can't be removed daily. During rainstorms, this debris gets washed into the gutter trough and clogs it, preventing proper drainage. Over time debris accumulates in the ...
See Articles

Flat Roof Drains and Strainers on Commercial Roofs – Watch Video

Drain Strainers on Flat Roofs
Flat Roof Drains and Strainers on Commercial Roofs Flat roof drains and strainers are the most important components of any commercial flat roof. They are responsible for properly draining any and all accumulated precipitation. To preserve the life of the roof, ...
See Articles

Flat Roof Drains: Location, Installation & Maintenance – Watch Video

Removing standing water on a flat roof/ Improving drain system
Flat Roof Drains: Location, Installation & Maintenance Flat roof drains require the proper location, installation, and maintenance because, as a system, it is fundamental to the preservation of a building's structure. We have seen many times that the location of a ...
See Articles

Flat Roof Drain Strainers – Watch Video

flat roof drain system
Flat Roof Drain Strainers are Important  If appropriately designed, a strainer is supposed to keep larger objects from going down a drain, while allowing smaller debris through with the water flow. Most strainers, or domes, that cover a drain on flat ...
See Articles

Best Flat Roof Drain System

Perfect drain system - less maintenance and less problems
A Flat Roof Drain - 15 years of performance A pleasant surprise about a flat roof drain on a commercial roof we installed more than 15 decades ago. After so many years I am still amazed how well it performs. The owner never ...
See Articles

Scuppers and Drains on Flat Roofs-Wilton, Darien to Greenwich

Scupper on an EPDM Rubber Roof - Flat Roof Repair - New Hampshire
Scuppers on flat roofs are best if correctly placed Scuppers are drain outlets on the edge of a roof. Our service is from Westport, Darien, Stamford, Greenwich, New Canaan, Ridgefield, Wilton, and Redding. A scupper drain outlet can be just a ...
See Articles

Gutter Repairs/ leaks on flat roofs? Stamford Westport CT

Gutter Iced Up during winter - Connecticut - Flat Roof Repair
Gutters constantly have to be cleaned out and re-adjusted Gutters repair is the often overlooked Whether residential or commercial roofs, whether slanted or pitched roofs, they all need gutter repairs. The best draining system is to have a slightly slanted ...
See Articles

Flat Roof Drains. Which is the best drain configuration? – video

Flat Roof drain
 Flat Roof Drains. Which is the best drain configuration? - video Placing or positioning flat roof drains in the right place is essential. Drains connect to pipes below the ceiling that will remove the water away from the building and ...
See Articles

0 Comments

Submit a Comment