Water wise: How to divert, direct and manage runoff

Unless you live in an exceptionally dry climate free of rain, you’ll need a water management plan to handle the rain water that runs off your roof. The right gutter system, combined with a drainage method, meets this need. Without it, water will spill off the roof and collect on the ground around your foundation, eventually working its way inside causing expensive water and moisture damage.


Why water means trouble

When the ground around the foundation is repeatedly soaked from water that drains off the roof, it creates problems both inside and outside of your home.


The trouble inside

The moisture that results from water repeatedly collecting around your foundation will eventually find its way into your basement, crawl space or concrete floor. Though the air in your home may naturally absorb some of the moisture, the excess moisture-heavy air can settle against cold surfaces like windows, attic plywood and inside exterior walls. And while condensation at windows may seem nothing more than a mere irritation, if left unattended it can cause fungal wood rot in attics and walls, leading to costly repairs.


The trouble outside

Water that runs off the roof and lands near the edge of your foundation causes a variety of problems. Erosion, for starters. And the repeated soaking and drying will cause your foundation to compress and compact; over time, potentially damaging your foundation Repeated soaking from runoff can also carry your topsoil down through any limestone draining material laid during construction, washing away your topsoil and clogging the drainage material and leading to more backups.


Gutter talk: Make the best choice

Choose the right gutter system for your home, and it will effectively channel the water off your roof and away from your home. But how do you know what’s “right?” And, once off the roof, where should all that water go? Here are a few key factors to consider when contemplating an effective water management system.


Gutter material

Gutters are made of many materials, with options to fit every style and budget.


Galvanized Steel is among the most economical, and typically available in painted or mill finish. They can be prone to rust and could require regular scraping and painting depending on the climate.
Aluminum can be formed, won’t rust and takes paint well and comes in many colors. Aluminum gutters are durable and relatively inexpensive making them the most popular choice.


Vinyl is impervious to rust and rot, but is only available in a few colors. Vinyl gutters typically have seams and may not have the strength to handle ice loads.


Copper has a beautiful, natural patina that doesn't require any finish and won’t rust. It is very expensive, and unfortunately often targeted by copper thieves.


Wood was popular in the past but rarely installed today. It is expensive, prone to rot, and requires ongoing maintenance, including painting and scraping.


Sectional and seamless gutters

Any gutter can channel water off your roof, but the style you choose can be tailored to match your, taste and budget.


Sectional gutters

Sectional gutters arrive in pre-cut sections that can be over 20 feet long, but cut to any size on site. Easy to hang and install, putting up sectional guttering is sometimes a DIY project. Depending on the material you choose, sectional gutters can be relatively inexpensive. However, because sections are seamed together they may develop leaks over time where sections meet. There is one type of system that creates free-floating gutters by using the roof apron for installation, but expansion joints also allow long spans to expand and contract rather than attach rigidly to the home. This is essential to assure maximum performance.


 Seamless gutters

The most common type of gutter is continuous seamless gutter, which is formed to custom lengths on site from gutter coil using a portable machine. This attractive option is free of joints and won't leak, but must be installed by a contractor. While zip hangers and spike and ferrule hangers are common, continuous hangers are also available to ensure long spans of seamless gutters remain free floating and not attached rigidly to the home is essential to assure maximum performance.



Gutter size vs. downspout size


Is it the gutter size that counts? Or is it the downspout size that really matters? 

The answer depends on the size of your roof area, and how many places there are to channel it into a downspout and eventually into a drain.


Most gutters today are Ogee and K, though half round is another style that is popular when trying to achieve a historic appeal. The most popular gutter size is 5”.  A larger 6” gutter is also available, but generally reserved for larger homes (to match the scale) or when roofing material like natural wood shakes or barrel tiles are used, which cast water far beyond the roof edge.


Rectangular downspouts are the most popular, and are offered in two basic sizes, 2” x 3”, and 3” x 4”. Round and square downspouts are also available. Rectangular and square styles may also feature a smooth or fluted face. If you have a large roof area with only one location for a downspout, the larger 3” x 4” gutter is a good choice. But if your roof is comprised of many smaller areas, a 2” x 3” gutter may suffice. If you live in an area with lots of trees over or near your roofline and are forgoing a leaf guard system on your gutters, a larger 3” x 4” downspout may help handle small debris and/or pine needles and reduce clogs.


What about outlet tubes?

Outlet tubes are the part that connects the gutter to the downspout. Ideally outlet tubes need to be sized to match the downspouts. For example, using a small tube on a 3” x 4” downspout, or using an oval or round outlet tube, may restrict the flow of water.


About roof pitch

Roof pitch is generally not a factor when considering the size of gutters or downspouts that are best for your home, with one exception. If the pitch of the roof is so extreme — or so low — that it causes the roofing material to significantly overhang the gutters, choose a bigger gutter. This will keep the water from overshooting the gutters entirely.


Create proper drainage

While it’s the gutter that carries rain off your roof, it’s the downspouts and drains that finish the job. Think of it as two drainage efforts — one for the gutters, and one to keep the immediate area where it drains clear. In small yards or those without a rain barrel or rain garden, getting gutter runoff away from the house is an absolute minimum requirement. This means that gutter downspouts empty above the ground, ideally downhill and at least five feet from your foundation (or as local codes specify).


If you can’t collect the water into a rain barrel or rain garden, consider a Curtain or French drain, which consist of a shallow, excavated trench filled with crushed stone, perforated drainpipe and filter fabric to prevent silt from clogging the pipe. The stone can be left uncovered or planted over. The excavated trench and the perforated pipe are both pitched slightly and run to daylight.


Avoid diverting runoff into streets or sewer systems. This further depletes ground water supplies, overtaxes city sewer systems, and dumps lawn fertilizers, pesticides, and pollution straight into rivers, lakes, and oceans. Some cities or counties will assess fines for doing so. Instead, consider green alternatives like building a rain garden to catch runoff — an environmentally sound and attractive way to deal with storm water. Or consider draining one downspout into a rain barrel and use the stored water to irrigate your lawn.


Consider special conditions

If you live in an area of the country with freezing weather, frequent rainstorms, many trees or other special conditions, there are factors to consider when choosing and installing your gutter system. Here’s what you need to keep top of mind.


Ice and water shield (also helpful in rainy climates)

If you are building a new home or getting a new roof, ask your roofing contractor if he is using ice and water shield, typically a sticky tarpaper that goes under first few layers of shingles. It’s very important to include in freezing climates to minimize any negative effect of ice buildup at the roof’s edge as the sun melts the ice. In warmer rainy climates, ice and water shield will ensure that there is no leakage when the wind holds water against the edge of your roof for a prolonged period of time during a storm.


Avoiding ice dams

If you have poor insulation in your attic and live in a cold climate, your roof is likely to develop an ice dam. Without proper insulation, the heat inside rises, melting the snow and ice on your roof, and then refreezing it on the edge. Heavy ice buildup from winter storms can sometimes cause the gutters to completely break off a home. Adding proper ventilation and insulation in your attic can help. Heat tapes or ice and water shield are also effective. Note: Caution should be used with heat tape on gutters, as downspouts could split if they don’t also have heat tape applied.



Drip edge

The drip edge is a sheet of metal material that fits under the shingles and guides water away from the roofing material, protecting the wood in your roof from getting soaked when it rains, or from a backup of ice. While a roofer usually installs it, soffit and fascia installers may also add drip edge. Unfortunately, builders looking to save money on construction and materials sometimes skip this important step. If you’re building a home or replacing your roof, make sure your contractor is adding drip edge! It is so important that the NAHB’s Green Building Guidelines  identify drip edge as a key building component.


Click here to download the Sustainability Technical White Paper




Know the installation facts

Now that you’re educated about the types of gutters, downspouts, drainage options and climate-specific issues, it’s time to focus on installations. A great gutter system will not perform unless it is installed correctly. As with any improvement to your home, you’ll want to do some homework first to make sure your installer is qualified to do the job, and has a proven reputation for excellent and reliable work. Here are a few key details you’ll want to discuss with your installer.

Screws and spike/ferrules

The most basic hanging system are gutter screws, or spikes and ferrules. With spikes and ferrules, the ferrule is inserted inside the gutter and the spike is driven through the rim of the gutter and through the ferrule to hold the gutter in place. If over or unevenly spaced the system can allow gutters to easily pull loose from the house during freeze and thaw conditions.






Hidden and zip hangers

Hidden hangers sit flat in the gutter, hidden from view, and appear at set intervals, such as every 24” or 32” depending on weather conditions and the overall gutter system. A screw goes through the back of gutter and a hidden hanger, holding everything in place. This strong attachment makes the front of the gutter less likely to distort or pull away. A zip hanger has a raised portion that makes it easier to apply; the screw is already inserted. Though it’s not quite as “invisible” as a hidden hanger, it is very fast to install.



















Continuous hanging system

A continuous hanging system is the strongest known type of gutter hanger and can be two- to three-times stronger than hidden hangers, improving the overall resistance to snow and ice loads as well as with ladder crushing. It hooks to the front of the gutter on the inside lip, or over the top, forming a bridge from front to back. A continuous perforated tray sits snugly on top of the gutter. This gives the gutter more strength and keeps it firmly attached to the house. As a bonus, the perforated tray acts as a natural leaf guard. 




What to ask your installer

Here are some specific questions to discuss with your installer. Though not all-inclusive, these will help you open a dialog and learn more about your options.


How will you create the corners?

You’ll want to know if your installer plans to use box miters, strip miters or custom corners. If you have a lot of corners, this is really important. If you don’t, then it isn’t a concern. Different regions tend to use different styles, so look at homes you admire before making your choice. Also ask about the accessories and miters available — you just might have a preference once you see the options.

Box miters create a seam in the corner and are pre-formed in the factory, reducing the likelihood of variation and saving time to prepare field-formed varieties.


Strip miters are formed  from gutter coil cut at a 45° angle to cover it. This type of corner includes a different design aesthetic than box miters. 


Custom corners are formed completely onsite from gutter coil and feature fewer seams but may vary more as a result.


Will you use zip screws or rivets to connect the system?

Throughout your system you will need rivets or screws to connect the various pieces.  A rivet gives a smooth appearance and hides the fact that it’s been fastened together. Screws are a shortcut, and more noticeable.

What’s the warranty?

From the gutters themselves to leaf guard systems, the best products on the market will offer long-term warranties from established companies. Read each carefully so you know what is, and isn’t, covered.


Leaf guard systems

A leaf guard system does just what the name implies: “guards” your gutters from filling with leaves and debris that collect over time requiring maintenance costing you time and money. There are a variety of styles available, each with different features.


Tension-type systems

Tension-type systems affix a helmet or cover to the gutter in an attempt to keep debris out while allowing water to pass through. These systems are usually expensive and may need to be removed during a re-roofing project. In addition, tension-type systems may require you to lift your roof shingles to place the leaf guard underneath — be careful, because doing so can void your roof warranty.




Filter-type systems

Filter-type systems are typically made of plastic. They often look like a sponge or bottle brush, and act as a filter to create a partial barrier to debris. These systems can become brittle from the sun’s intense rays and break down over time; they are also prone to mold and mildew growth because they can retain water.


Barrier-type systems

Barrier-type systems offer a wide variety of options, from inexpensive plastic or wire mesh to perforated aluminum systems that block everything except the smallest debris. Aluminum options are preferable because they are more durable and can withstand years of abuse from the sun and animals. Hole size is very critical as the smallest debris entering your gutters can collect over time and cause clogs. Even though the hole looks small relative to the size of a leaf, keep in mind that leaves are brittle and break down, creating smaller leaves and twigs, all of which can enter your gutter and collect over time — increasing your chance of clogs.