Water Removal: A Continuing Story
by Bill Laney, Murr-Laney, Inc.
Every building collects water and sends it to the outer perimeter. There the water is taken off the
roof in roof drains and internal leaders, through scuppers, conductor heads and
downspouts, or gutters and downspouts. Because of ordinances relating to water
run-off, very few buildings allow water to run off the edges.
Thought and planning on water control has to be an essential part of design considerations of any building. These decisions add many dollars to the cost factor. Large roofs will have the slope built into the structure or the roofer will install tapered systems to form a series of crickets to channel water to the drains. On smaller roofs the slope may be to both sides, or the entire perimeter. The water will be channeled away by roof drains or scuppers in a parapet wall. It must be a gutter large enough to handle the runoff.
On steep roof buildings little thought has to be given to the center sections as the water will get to the eaves. This eave can be as simple (in most instances) as continuous machine run gutter, to a little more complicated, special design and fabricated gutter. The eave may have a parapet wall (especially older buildings such as churches) that has a series of copper or membrane covered crickets sloped to scuppers.
So, all this means is that all water-carrying methods are unique. Who knows when or who used or designed the first gutter. It was probably wood with asphalt coating or white lead paint or putty for waterproofing. The cypress wood gutters that I have seen were lined with copper. Metal gutters have been around for many decades. In fact, most roofing companies had hand-breaks with a set of cornice rolls, or half-round gutter machines. Frank Market with the former City Roofing Company (Charlotte, NC) was proud to show his wooden half-round gutter machine. Boy, that was a work of art!
As a side bar: If anyone reading this article knows of any of these old antiques, please call me or Carla at the Association Office. This could make for an interesting contrast with the continuous gutter machines. Maybe a little competition! Sorta get carried back to the old days!
The hangers for half round gutter was twisted wire; then flat rival type hangers that conformed to the gutter and a strap turned up to be fastened into the sheathing board or rafters. You can still see stubs of these old hangers on older houses and buildings where they were cut off to make way for new gutter. Half-round gutter can still be suspended by the old strap hangers or an assortment of hangers such as circles and shanks, cast hangers or stamped circles and shanks in one piece. The configuration of the fascia determines the hanger to be used. A crown mold eave will need roof-mounted hangers; whereas, the fascia mounted hangers such as the cast hangers need a vertical fascia board. Halfround gutter now can be purchased in several styles and from most of the metals that you use.
Since I grew up in a roofing and sheet metal household, I learned about gutter early. After Pop taught me the fine points of gutter, every rainy day I would be in the shop joining 10-foot sections of OG with tinner’s rivets and threepound soldering irons heated in a charcoal fire pot. Many of the old timers in the roofing profession started out this way. All the gutter was installed with spikes and quills.
Sheet metal workers can now get OG or K style gutter from 5” up to 8” run through gutter machines in any length the customer is able to transport. Or the machines can be taken to the job site. All gutter has special concealed hangers. Occasionally larger gutters need extra support in the form of exterior hangers. If we could back up and make any changes in the formation of machine run gutter, it may be to increase the height of the rear leg.
We have sheet metal fabricators in our Association that supply
most of the gutter mentioned to this point. Special designed gutter
required to form part of a cornice or match a particular mold requires
hand fabrication – whether it be hand break or auto break, which has
almost replaced the old press breaks. The computer break capability is
growing in our area and can now produce up to 40-foot lengths.
Built-in gutters have suffered an undeserved reputation because of the belief that they cannot be installed leak free. I will admit, improperly installed, it can be an eternal problem. The last specification that I read concerning built-in gutters on a job called for terne coated stainless steel liner with an overlay of EPDM for safety. My question was is that a misunderstanding on the part of the designer, or a doubt in the ability of the roofing bidder to fabricate and install this type of gutter system and it be leak-free for the life of the roof?
A few considerations apply to built-in gutter that do not apply to hanging gutter:
- The material should be a solderable metal (16 oz or 20 oz copper, lead coated copper, terne coated stainless steel, stainless steel or G-90 galvanized).
- Joints should be lapped 1-1/2”, stagger riveted one-inch on-center, and fully sweated solder with 3# or 6# soldering irons. Sealant should not be used in built-in gutters.
- The gutter should be free to move, no nailing or restricting. The outside lock edge and the rear eave strip should be separate. If the gutter is extremely large, two breaks in the corners will prevent the sharp bends and add columnar strength to the runs.
- Expansion joints should be installed to at least 1/2 inch above the lowest part of the gutter to prevent overflowing in case of clogging. Normally expansion joints are not installed at the miters even though they can. The placement and quantity of the downspouts will determine the frequency of expansion joints.
- A well-designed and installed built-in gutter can be an enhancement to a building. It is not damaged by snow and ice.
In conclusion, no gutter system regardless of the size, design or material is miraculous. They all require the same determination and craftsmanship approach because what our profession is all about is there for all to see. As I see it, the learning curve has not peaked yet in our battle and search for the ideal water handling system. A given fact is that water and debris will flow over the side. Also a given is that a gutter and downspout system must be maintained by regular cleaning from roof to the ground.