CBD's Metal Information Page

What Metal is Best for a Roof Cap?

Painted or Galvanized Steel: is a cheap and strong metal, but it will rust out far too soon to be practical (as seen in this photo). Even a cheap roof cap that cost only $20 is too expensive considering the trouble and cost to replace it every 10 years to avoid the permanent rust stains that will occur if it is not replaced. Although a well built copper cap should last well over 100 years, being reused each time the roofing is replaced.

Amazingly; painted steel is by far the most common metal used for roof flashing still today (well over 20 to 1), only because it is a little cheaper than aluminum. Most professional roofing supply distributors here in the NW do not even stock aluminum flashing, since the roofing contractors won't buy it. The savings to you as a Homeowner is marginal, since most of the cost of any construction work is labor. Even though copper cost 500% more than aluminum, steel only saves you less than 10% off the cost from using the thick 20oz copper we use, so we do not even offer steel as an option.

Galvalum: This may be better than galvanized or painted steel, but again it is not worth the small savings difference from using copper, so we do not offer this option either.

Aluminum: is around 1/5th the cost of copper. It can be used for roof caps, but that sheet metal is painted to make it less brash looking and keep it from get so chalky looking from the oxidization. It has a good baked on enamel finish, but it still only has a 20 year life span on the painted surface. After that hit will look really bad as the paint flakes off, but it will still protect the roof for decades later. the repair would cost more to have it stripped down and repainted than to have a new cap made. aluminum or the painted surface will also mildew. So because of these issues; we have not had any clients even ask about this option, since the savings would be marginal for custom work like ours.

Lead: is the most commonly used metal for these roof caps (as shown here). Aside from the cost, roofers love lead, because it is such a soft metal that can be easy cut and molded quickly without any special tools. It just takes a pair of household scissors to cut it and your bare hands to shape it. It can be custom made right there on the roof peak in just a couple minutes. It is so heavy it does not even need to be nailed down to the roof. It will last just fine, but it does not leave much in the way of a decorative option.

Stainless Steel: is a good strong metal that will last, but it remains that shinny mirror-like finish, which stands out like a sore thumb until it mildews. Since it is about the same cost as copper, but without the anti-fungal properties of copper, it is rarely requested, but strongly pushed by other sheet-metal shops for the reasons listed here:

Warning: Other high-end shops will push stainless steel like it was the best thing on Earth. Especially for chimney caps. That is because stainless steel is quick to fabricate, since it can be simply spot welded together. They also do not need to worry about finger print oils making the metal surface tarnish unevenly. Another reason you need to beware of this scam is how they will say they are making it with stainless steel, but will actually use galvanized steel, since they they know you will not see it start to rust for about a decade later. Well past the warranty period they may offer. Very often some parts of it will not be stainless steel like the screen, rivets, or bolts. Again; you can test this with a magnet. The good stainless steel we used to make these roof caps does not attract a magnet at all.

Brass: is just copper with 30% zinc mixed in to help reduce the cost and gives it that temporary yellow look. It will still tarnish and turn black with age. The zinc is a very soft metal, which makes brass a softer sheet metal than copper, requiring a little thicker sheet to have the same dent resistance, so it is pointless.

Copper: is clearly the best long lasting value. A small sheet of thin copper can be cut in a circle with scissors with a cut to the center to hand bent into a simple overlapped cone shape, and nailed in place, but it would not be reusable. That simple small cone shape is what you may see most commonly when any metal is used since most roofers are pretty simple people. Here is the best attempt we have seen a roofer try to make. It was for our clients the Bogaards in Alabama (you will notice we did not place our trademark on this photo we had taken here in our shop). They sent us these copper caps to use as a roof angle template. Below is the new larger set we made for them with thicker copper and finial support pipes built in. They were redesigned to be in proper proportion to the individual turret roofs.

We work to do a decent job with thicker copper that will not deform or dent so easily, then accurately bent with the same number of sides as the roof, then securely screwed in place with stainless steel screws makes a better looking cover seal that will last and can be easily reused. That is why we provide the stainless steel screws with our fabrications. With any custom fabrication the labor is what costs the most, so using a cheaper metal is foolish.

Copper is one of the few metal that are meant to be seen. It will tarnish within a few months to a satin brown. It actually takes nearly half a century to turn that chalky green, unless special acids are applied to quicken this tarnish effect. This dark earth-tone look makes copper a lot more appealing to most people. Not so brash looking as with most other metals. It will stay clean, since it will not mildew. It will also retard the growth of moss on the roofing below it. The thicker 20oz copper we use is very good for archival quality to last for well over a century if built well.

Copper also makes a great ridge cap for any roofing in areas that suffer from moss growth and would keep the top edge of the roof sealed better than the roofing shingles.

Warning: Copper thickness is described differently that other metals. It goes by weight per square foot. If they list it as 24 gauge; that would mean it is only a thin copper plated steel at best. The 20oz copper we use is about twice that thick. Other sheet-metal shops may claim they use a thick copper, but they often still use just a thin copper to save on cost. Or worse yet it is only copper looking painted steel (as shown in this photo). Solid copper will not attract a magnet, so this deception is easy to test for. The problem is that you cannot test for this until after you have taken delivery. At that point it is too difficult to resolve given the added time delays and cost, so they count on the fact that few clients will bother to check or complain if they had realized they were ripped off. We are happy to mail you a free sample of the 20oz copper we use upon request. We have lots of small scraps.

Bronze: is just 70% copper with other metals added to make it harder, so it is too hard and brittle to bend. It is primarily used for casting. I have not seen it in sheet metal form.

Titanium: would be fantastic, but too hard to work with and it is still far too expensive.

Silver: would be great, but way too expensive, so we have not even had any serious inquiry for a sterling silver roof cap. But I'm sure it could be done.

Gold: even a low grade 10k gold with lots of silver and copper mixed in would be excellent, but only for those who have money to burn. We have yet to meet such a client (LOL).