Roof Downspouts

There are many options when choosing by material, performance, and durability. Installing a simple, standard downpipe system may be more difficult than expected, while more complex systems with numerous unfamiliar parts can be surprisingly easy and fast.

Material

Downpipe systems are made from several materials: sheet metal, galvanized steel, colored metals, metal with polymer coating, and plastic. The material significantly affects system performance and, in particular, its expected lifespan.

• Galvanized steel and sheet metal downpipes are attractive due to low cost. Another advantage is savings on hangers, as these systems are lightweight and require fewer support elements for stability. However, their main drawbacks are short lifespan and metal corrosion. Even galvanized steel corrodes if scratched or hit. Damage also comes from nature: acidic rain, ice buildup, and decaying leaves. Expected service life: 8–12 years.
• Metals with polymer coating eliminate the main drawback—corrosion. The coating also protects against UV rays and minor mechanical damage. However, do not test strength by tapping with a hammer—damage will occur. These systems withstand repeated freeze-thaw cycles and do not deform. Expected lifespan: 50 years.
• Colored metals (copper, aluminum, titanium-zinc) are lightweight and do not require complex mounting. They are strong, reliable, and expand thermally, making them resistant to many freeze-thaw cycles. These metals are flexible and soft, so they resist mechanical damage—may bend, but won’t leak. Drawbacks include high installation cost (requires soldering) and limited color options (natural metal color, not painted).
• Plastic downpipes are widely used. Advantages include:

• complete kit (all hangers, brackets, elbows, and more available in one package);
• easy installation (can be done independently);
• resistance to UV and acidic precipitation;
• high mechanical strength.

The only significant drawback is high thermal expansion (not recommended in regions with extreme daily temperature swings).

Design

A downpipe system consists of many components. The main ones are gutters and downspouts. Other parts are considered auxiliary, though they may cost as much or more than main elements. Before choosing a system, review its full component list. Essential parts include:

• end caps for downspouts;
• inlets (funnels to direct water into downspouts);
• connectors and couplings for joining gutter and downspout sections;
• hangers to support gutters;
• clamps to secure downspouts to walls.

Optional but useful additions: leaf screens to prevent debris from clogging gutters, corner sections for gutter bends, and rainwater collectors for harvesting rainwater to irrigate gardens.

Downpipe System Sizing

To determine how many and which parts you need, calculate your downpipe system. First, decide where it will be installed:

• small roofs (e.g., gazebo or porch overhangs) require gutters up to 115 mm in diameter and downspouts up to 70 mm;
• medium-sized roofs (small cottages, country homes) need gutters 115–130 mm and downspouts 70–100 mm;
• large roofs require larger sizes: gutters from 130 mm, downspouts from 90 mm.

To ensure effective drainage, calculate the number of downspouts based on roof area and eave length. Manufacturers usually indicate the maximum roof area one downspout can handle.

Usage Tips

To ensure long service life, maintain your downpipe system at least twice a year—after leaf fall (autumn) and after snow melt (spring). Clean gutters from dirt, fallen leaves, debris, and moss using a non-metallic brush, plastic scraper, or high-pressure water jet. The goal is to remove large debris, not to scrub clean. This way, rain will not cause damage, and your walls and foundation will stay safe.