Heritage Restoration, Inc.

Metal Roofing and Repairs: The Good, The Bad, and the Real Ugly

The Rhode Island economy was booming in the 1880s. The economic prosperity created some of the most spectacular late 19th century architecture across our state, with styles like Second Empire and Queen Anne having complex mansard roofs, curved window hoods, wrap around porches, turrets, and other whimsical details. These details were typically covered with metal roofs made from copper, lead, tin-coated iron, and terne-coated steel. Today, these roofs and details have outlived their useful life and what is worse, have been improperly layered and maintained.

Metal roofing and flashing has been around a very long time. A copper roof was installed on the Loha Maha Paya Temple in Sri Lanka in the 3rd Century B.C.. The Romans used copper on the Pantheon in 27 B.C.. The copper roof of St. Mary’s Cathedral, Hildensheim was installed in 1280 A.D. and still survives to this day. Metal roofing and flashing provides function, beauty, and longevity, although it is not the material alone that can last for centuries. Metal roofing and flashing is a craft. Knowing how to use the metal is as important as the installation techniques. Too often perfectly good metal is prematurely torn off from improper installation and poor maintenance.

Historically, many metal roofs were coated with red iron oxide linseed oil paint. Around the 1950s, aluminum oxide paint was introduced as a protective coating. Today, there is a myriad of coatings for existing metal roofs, some better than others.

Soldering copper pans are not the same as soldering copper plumbing.  It should be clean, well covered, and not look like this

Soldering copper pans are not the same as soldering copper plumbing. It should be clean, well covered, and not look like this

Lead chimney counter flashing is great, but very soft and vulnerable to poor installation

Lead chimney counter flashing is great, but very soft and vulnerable to poor installation

Face nailing, caulk, and bad laps do not last

Face nailing, caulk, and bad laps do not last

Tar is not flashing, period

Tar is not flashing, period

It is very difficult to repair old metal with a new piece of metal. To get a good bond, the metal has to be perfectly clean, correctly heated, and most importantly properly, soldered. The best details do not to rely on a solder joint alone, but use a hem or lock joint to help keep metal together. The easiest fixes, like tar, roofing cements and other sealants in a tube, are actually not repairs at all, but quick failures.

Many choose to go directly over the metal with EPDM, or rubber. The trouble with

A soldering iron and bar stock is the ONLY proper way to solder copper pans and flashing

A soldering iron and bar stock is the ONLY proper way to solder copper pans and flashing

A proper soldered copper joint first bonds the metal, then covers with solder to protect the joint

A proper soldered copper joint first bonds the metal, then covers with solder to protect the joint

rubber is it needs a great bond for seams to last as long as the rubber itself. And metal spouts where the water drains are the first to fail and a pain to replace. So many keep the spouts and cut the rubber around it, using a lot of sealants to simulate a bond. The bond is short lived, lasting only about 1-5 years until the repair is useless.

The real concerns with metal repairs are holes and movement. Many coatings only protect the metal, and are not designed fill gaps or bridge cracks. Many products are actually systems and neglecting to use the full system will shorten the life of the repair. Elastomeric compound coating systems are great for all kinds of surfaces, aiding in the protection and longevity of metal roofs. Other repairs like EPDM are only as good as the full system, replacing all components such as counter flashing and spouts, and not relying on caulks and sealants that are not compatible with the longevity of the EPDM. And of course metals like copper are great and can last for over 100 years, as long as they are done right.

EPDM seams must be properly cleaned to make a good bond.  Also, lap sealants and/or uncured seam tape can prevent seam failure.

EPDM seams must be properly cleaned to make a good bond. Also, lap sealants and/or uncured seam tape can prevent seam failure.

Existing old metal spouts should be removed when installing an EPDM roof.

Existing old metal spouts should be removed when installing an EPDM roof.

Nails through a copper roof will make it leak, as well as rot from galvanic reaction.

Nails through a copper roof will make it leak, as well as rot from galvanic reaction.