A Brief Rain Gutter History

Until the late 19th century virtually all rain gutters were made of wood.  With the advent of metal roll forming machines around 1900, the ability to create metal gutter became possible.  The roll forming process shapes metal into long, formed sections.  The photos below of early 20th century rain gutter at the Presidio in San Francisco show the beautiful and architecturally pleasing half round rain gutter common at the time.  Award Metals continues to produce half round rain gutter for a classic yet distinctive theme.


Presidio in San Francisco

Click on photos to enlarge

Up until the 1970’s, most rain gutter was produced in factories on stationary roll forming machines weighing up to several tons.  Beginning in the 1970’s, lighter portable roll formers on trailers became available.  With portable roll formers, contractors shape unformed metal, from a coil, at the site of installation.  Today, the industry manufactures rain gutter both ways.  Award Metals participates in both markets, producing steel rain gutter in our factories, and providing unformed pre-painted steel coil, through our distributors, to contractors who fabricate finished rain gutter at the installation site.

Roll forming machines at Award Metals' Union City, CA plant.

Painted Steel Coils
Portable roll former on trailer.
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The Strength of Steel

Award Metals produces rainware products using top quality coated steel and copper (more on coating later).  The durability and performance of steel and copper surpasses other rainware metals, particularly aluminum.  Steel and copper stand up to ladders, fallen branches, footsteps, hail, snow, and ice in situations where aluminum can’t.

Temperature changes affect all metals.  A 50 foot length of steel will expand or contract about 1/4” with a 50° temperature change.  Aluminum changes at about twice that rate.  Because of expansion and contraction, rain gutter can warp and bow between anchors and allow water to drip behind the gutter.  This tendency increases with aluminum because of its greater rate of expansion, particularly on longer gutter runs.


When we need the strength and durability of steel, we see it in common household items.

Click on photo to enlarge.

At Award Metals we use .019” steel (also commonly called 26 gauge) for rain gutter.  The toughness of 26 gauge steel has proven itself since the early days of roll forming.  We do not produce rain gutter in lighter 28 gauge (.016”) or 30 gauge (.013”) steel.  Aluminum gutter metal comes in two thicknesses, .027” light duty and .032” medium duty.  Because of its inherent lack of strength, the thickness of aluminum rain gutter coil must be greater than steel.   Most installers of aluminum use .027” because of lower cost and the difficulty in adjusting roll forming machines to accept the less common .032” size.

A Case for Coatings

Steel gives lots of strength.  However, unprotected steel exposed to the weather oxidizes.  We see this in the form of rust.  Rust doesn’t play a significant role in shortening the life of steel gutter provided a quality coating is used.

To make steel last longer, it is common to protect it with a coating of zinc (galvanized), or a mixture of aluminum and zinc.  There are many trade names for this aluminum-zinc coating including Galvalume®, Z-Nal™, and Aluzinc®.  A galvanized coating is 100% zinc, while an aluminum-zinc coating is 55% aluminum, 43% zinc and 2% silicon.  All Award Metals rainware products use galvanized or aluminum-zinc coated steel.

A G90 rated coated steel provides the optimum protection for galvanized rainware. G90 means that there is 9/10 of an ounce of zinc per square foot of steel (both sides combined).  Protection is directly proportional to the thickness of the zinc coating.  For example, a G60 zinc coating has 6/10 of an ounce of zinc per square foot.  A G90 coating offers 50 percent more protection than G60 and 125% more than G40.  Award Metals uses G90 exclusively for our galvanized rainware products.  Many others use a G60 or G40 coating because of its substantially lower cost (zinc is expensive).  Award Metals’ bonderized (primed, ready for paint) steel gutter and downspout have the primer coat applied on top of a G90 galvanized coating.

Aluminum-zinc coated steel combines the excellent corrosion protection of aluminum and zinc resulting in an outstanding resistance to the elements.  Award Metals’ painted steel coils for the portable roll forming market use an aluminum-zinc coating exclusively.

A Primer on Paint

Award Metals’ painted aluminum-zinc steel coils come with a factory applied, baked on polyester finish.  Paint processing takes place in a continuous process and includes:

  • Cleaning and the application of a pretreatment to promote adhesion between the primer and the aluminum-zinc coating.
  • Application of a flexible, high performance corrosion resistant primer.
  • Application of a colorful and durable high grade polyester topcoat.

The “South Florida Exposure” test, used by the paint industry, measures durability.  South Florida has the strongest paint deteriorating UV rays in the country and provides a perfect environment for paint testing.  Award Metals’ high grade polyester paint withstands a 10 year test without cracking, blistering, or peeling.  Many suppliers of painted rain gutter coil use a lower grade paint that meets only a 5 year test.

Coordinating with Color

To begin, determine what features on your home you want to consider a trim item to highlight.  Generally, rain gutter is used as highlighted trim with downspouts deemphasized (more on downspouts later).  For example, if your home is painted yellow, make sure the rain gutter color you chose works with that hue.

It’s best to emphasize your home’s attractive architectural features with contrasting color, either lighter or darker.  Minimize features like downspouts by using uncorrugated pipe and blend them by painting them the base color of your home.


Los Gatos, CA

San Carlos, CA

San Francisco, CA

Photos of attractively painted homes emphasizing gutter color and deemphasizing downspouts.  Uncorrugated downspouts blend nicely when painted the base color of the home.  Try finding 4 downspouts on the home at the far left!

Click on photos to enlarge

Award Metals offers rain gutter coil in 12 colors, providing a broad array to avail yourself in beautifying your home.  Our color palette can be viewed here STEEL RAIN GUTTER COLORS.  Keep in mind that computer monitors will not give a completely accurate color rendering.

Details on Downspouts

Award Metals produces flat-faced steel downspout, the strongest and longest lasting type.  Market studies show that most homeowners prefer to deemphasize downspouts by painting them in the base color of the home and by using flat-faced uncorrugated pipe.  Our white painted or bonderized (primed, ready for paint) downspout can be used and blends well as is, or can be painted at a later time.

Because of its light duty nature, aluminum downspout uses corrugated material to try and add strength.  We recommend that aluminum downspout not be used in areas where there may be a chance of contact beyond a light bump.


The homeowner placed a potted plant to protect corrugated aluminum downspout after contact.
Corrugated aluminum downspout crushed. Damage this severe will cause backups and roof damage.
Protect corrugated aluminum downspout by shielding with shrubs or other fixed objects.
Click on photos to enlarge

As we discussed in the section on steel coatings, Award Metals uses only G90 galvanized steel or aluminum-zinc coated steel for downspout, providing the ultimate in corrosion protection.

Consideration of Costs

Award Metals manufactures a multitude of products in steel and aluminum.  We feel qualified to express our opinion about the applicability of metal types for certain uses.  When we consider cost, durability, and long life, quality coated steel wins hands down over aluminum for rainware products.

Pay less for more?  It’s hard to believe, but that’s what quality coated steel offers.  Foot by foot, high grade G90 galvanized or aluminum-zinc coated 26 gauge rain gutter steel costs substantially less than aluminum gutter coil.

Hopefully this section on rain gutter provides the information that a consumer needs in making an informed decision.  If you decide to use steel, remember, specify G90 galvanized or aluminum-zinc coated steel.  Better yet, ask for Award Metals products!