How to Install Gutters On a Flat Roof

How to Install Gutters On a Flat Roof

Most homes are designed with pitched roofs and typically steep angled rooftops. However, flat rooftops have been associated with industrial buildings for a long time, but there are flat rooftops in more homes in the real sense than we may believe. Flat rooftops have their unique construction of the drainage flows. We have three drainage options for flat rooftops, namely: scuppers, internal drains, and gutters. Before deciding what option to use for your flat rooftop, ensure you get familiar with all of them. If your flat rooftop has a slide slope, you should major in how to install gutters on a flat roof because that is the appropriate option. 

Here are some of the steps ideal to follow before installing gutters for flat roofs:  

Ensure proper drainage

A well-constructed gutters for flat roofs should drain water quickly without forming ponds of water. Water must drain off quickly to avoid build-up, especially when temperatures are below zero degrees and can freeze standing water. It means that a flat roof needs to be constructed with a slight slope to let water drain to the gutters easily. Even when a small amount of pooling occurs, it shouldn’t affect the roof’s overall performance. 

Choose a flat roof gutter design

A flat roof gutter design should include a drainage system with gutters, scuppers, and a downspout. Good roofing should include primary and secondary scuppers for emergency purposes. Use metal flashing if there is a steep roof above the flat rooftop and the top of the metal overlaid with tiles. You might install drains fixed with strainers to catch debris. 

Choose the best materials

Choose gutters made from the best material, i.e., galvanized steel, aluminum, copper, or vinyl material. It requires soldering for galvanized steel; hence, you might need professional assistance from a technician when installing. But you can DIY if you have all the tools. After installation, the painting should be done regularly since galvanized steel is prone to rust, but overall, it is the best option for gutters. Aluminum is a good material for gutters owing to its lightness and its rust resistance. What’s more, they are available in a variety of colors. The only problem with aluminum is that it is less sturdy compared to galvanized steel. 

The vinyl option is easy to install and more so impervious to rust or rot. However, when the weather is extreme, it can warp and become prone to splitting. But it can last in temperate conditions. In comparison, copper options can stay for a long time without needing maintenance except for keeping them in a free-flowing position. 

Flat roof gutter system

If you want seamless flat roof gutter system, you need to hire a contractor because they are custom-soldered using a portable machine. The good thing with the seamless option is that they don’t leak easily. 

A guide on how to install gutters on a flat roof

Take comprehensive measurements of the overall roof and decide where to place downspouts. Cut the gutters according to the measurements using the hacksaw wearing protective gear to avoid injuries. Assemble the gutters on the ground giving an allowance of 2 inches’ overlap. Drill holes at each overlap to secure gutters with rivets using a rivet gun. Seal the underside of the overlap with caulk or sealant. You can use a string while placing the gutters considering the gradient to ensure water drains freely when the gutters are fastened in place. You can use hooks and screw them onto the fascia boards at an interval of 18 inches or thereabout. 

At the end of each gutter, install a downspout to follow your property’s sides to the ground. Finally, use a gutter sealant to attach to a downspout to waterproof it. Aluminum mounting straps can provide added security. 

Prevent weathering issues

Suppose you have cavity walls, fit weep holes with cavity trays to prevent water seepage. Flashing is a sure way to waterproof joints. You can use lead metal to overlap horizontal mortar joints and to edge the roofing materials. Your drainage should be functional with all these measures in place. 

After installation, keeping your gutters clean is essential for them to remain functional, especially if you are harvesting water for domestic use from the gutters. If presented with blockages, the drainage will become problematic because water will then overflow, forcing its course to unwarranted areas. Besides, when water overflows inside the gutters, chances are, they might pull off the gutters from the fascia board, collapsing them completely. Overflowing water can tamper with the brickwork or rot the woodwork framing on your property; hence your property will not live up to its life expectancy. 

If you can’t clean your gutters on your own, remember you can hire a professional to do the job. In the case of galvanized steel that requires periodic painting, a professional painter can do the cleaning and the painting job on the same contract reducing the cost of maintaining your gutters significantly. 


The difference between pitched rooftops and flat rooftops is visible; pitched roofs have valleys and tips while flat roofs have slight sloppy levels but cannot shed off the water as rapidly as pitched rooftops. Gutters are the most viable solution for draining water off a flat roof. They easily direct water outside the structure towards the downspouts. A flat roof isn’t in reality as level as it sounds, and it should direct water towards the gutters in one direction. You can also combine gutters with working hand in hand with the scupper system. Now that you know about flat roofs, it is important to install a suitable drainage system to prevent damages to your garden, rotting on wooden frames, or damaged exteriors. 

You now understand how to install gutters on a flat roof made from different materials. Galvanized steel is the most viable option for gutters, only that it is prone to rust. Aluminum is rustproof but not sturdy, copper is good for gutters only its high-end in terms of cost, and vinyl is flexible and you can self-install, only it can bow to weather elements. 

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