The Best Drainage Solutions for Flat Roofs

Flat roofs offer a unique look for buildings. Historically, flat roofs are most common in commercial construction. However, recent design trends have led to an increase in flat roofs for residential homes, too.

Keeping Gutters and Drains Clean

Not only do flat roofs provide multiple benefits and a simple, modern look, they are also more resistant to persistent environmental threats. If you want to get the most out of a flat roof design, you can turn it into a unique, private living space! You can set up a community garden on one side of the rooftop and enjoy grilling up the fresh vegetables in a patio on the other side. Functionality for a flat rooftop is one of its greatest perks.

The challenge comes with heavy rain, snow, sleet, and hail. When heavy precipitation falls on a flat roof, where does it go?

Rain and snow fall down on all roofs, flat and slanted. But, if you have a flat roof, it has nowhere to go. That’s why having a strong drainage solution in place is so important. When you don’t utilize the proper drainage solutions, water will quickly pool on your roof and put unnecessary stress on your building’s foundational support.

Over time, continual pooling water leads to annoying leaks, overall structural damage, a persistent accumulation of debris, costly deterioration, and eventually, necessary roof replacements. It’s easy to protect your roof from these problems, as long as you don’t wait until it’s too late. Instead, make sure you have an effective drainage solution for flat roofs in place today.

Here are some of the best ways to ensure your roof is ready to brave the elements:


Most roofs come equipped with a gutter system; this is the most popular roofing drainage system. The goal of a gutter is to drain the water out and away from your property’s foundation for structural protection.

Don’t let the term “flat roof” mislead you into thinking that gutters are not effective for this style of roofing. Though flat roofs are almost level in comparison with their steeply pitched counterparts, they are not completely flat. They do have very low slopes that allow to them drain water. Gutters collect the water that naturally falls off your roof into open piping systems. They then lead the water off and away from your home or building. Gutters are by far the most cost-effective drainage solution for flat roofs, but they do need to be regularly cleaned and maintained for the best results.

One of the easiest ways to ensure that your gutters stay clean and clear of any debris is to avoid allowing trees or bushes to hang over the top of your roof. If this is problematic, you’ll find yourself on a ladder cleaning out your gutters frequently throughout the year.

It’s important to note, there may not be a gravitational pull for the water that lands in the center of the roof to direct it toward the gutter system. There are ways to combat this, but they can get costly. It’s best to bring in a professional to inspect your roof before making any final decisions.

Interior Drains

Another type of drainage system that works extremely well for a flat roof is an interior drainage system. This works by placing drains across intervals near the middle of the roof that lead first inside, and then out through a series of gutters and pipes.

The internal network is efficient at reducing the amount of pooling water that often accumulates near the center of the roof. To prevent any debris from getting trapped inside, interior drainage systems are equipped with strainers. If you get this type of drainage system, you need to ensure that the strainers are working properly, and nothing is getting through.

Cleaning exterior gutters is time consuming, but easy when compared to cleaning interior drains. Luckily, this type of cleaning can easily avoided by ensuring your strainers are in place and functioning properly.

The best part about interior drains is the fact that they’re hidden from the outside view of your building. This creates a seamless aesthetic that’s perfect for both homes and commercial buildings.

The downside to interior drain systems is that when damage does occur, professionals need to be brought in. While they’re stronger and more protected, they are also inside the building.

When interested in an interior drain system, it’s best to get an accurate estimate for your project. They do tend to be more expensive than other types of draining systems, especially when comparing them to simple gutters. However, if you’re prepared to commit to an upfront investment, it’ll be well worth your while.


Another potential drainage solution for flat roofs is to install scuppers. Scuppers are similar to gutters because they are installed along the edge of your roof. However, they work a bit differently. Unlike gutters, which collect water and lead it out through a downspout, scuppers work primarily to expel water out and away from the roof. They’re smaller and don’t line the entire edging of your roof. They’re a bit longer and more strongly angled downward, so that gravity can help push the water off your roof with the momentum needed to keep walls and siding dry. This momentum also ensures that the foundation of your building isn’t exposed to excess amounts of water.

To get the most out of scuppers, it’s advised to pair them with a roofing system that helps direct pooled water. This is best done using a tapered insulation system. It’s also possible to achieve the direction you need using a sloped structure; this can, however, can add a lot of excess stress to your roof.

The only downside to using scuppers in the Midwest is snowfall. They aren’t very efficient in managing melting snow and ice. Severe weather can also damage scuppers. Otherwise, they are one of the best options for flat roofs.

True Sloped Insulation

True sloped insulation is installed underneath a roof. It works by utilizing gravity to expel water. Because of how this is installed, it’s not a great solution for existing buildings, but a viable option for new construction.

True sloped insulation is made out of EPS board, wood fiber board or ISO board thermal insulation. This insulation style must be pre-cut by the manufacturer to the exact measurements of the flat roof. Professionals then install the slope pattern to create a ramp that guides water away from the flat roof’s surface.

The small slope that’s installed acts as a ramp to avoid any excessive pooling. It also guides the water off of the surface. Note, this draining solution is the most expensive option.

Step Sloped Insulation

If you like the idea of true sloped insulation, but don’t want to spend thousands of dollars, you can opt for a step sloped insulation. The general idea is similar: add a slight slant to your roof to get water off and away. However, step sloped insulation uses flat board insulation instead of the roof-board that true sloped uses. This is more cost effective because of how it’s installed.

If you’re interested in either insulation option, it’s advised that you contact a professional roofing company to schedule an inspection. Only the professionals will be able to give you the advice you need based on your roof’s specific parameters.

Calling in the Professionals

There are a variety of different options when it comes to selecting a drainage solution for flat roofs. Whether you are thinking about upgrading your current system or selecting one for a new building, it’s best to bring in the professionals. There are few things worse than a drainage system that isn’t working. Working with a professional can give you peace of mind and can help you avoid some disastrous problems down the line.

If you’re on the market for highly skilled professionals, then look no further than Advocate Construction. We’re a team of experienced contractors that work efficiently with every budget. All of the jobs are done with high levels of integrity, transparency, and with longevity in mind.

Give us a call at 833-409-ROOF (7663) or contact us today!