The first vertically aligned downspout in recorded history was used on the Tower of London in the year 1240. It was installed to keep recently applied, wet paint from washing off in a rain storm. Thus, while downspouts are not at all a new invention, their status has certainly progressed from an ad-hoc measure to an essential piece of equipment.
The Purpose of Downspouts
One of the alternate names for a downspout, “roof drain pipe,” is quite descriptive of their purpose. The function of modern downspouts is to direct water down from the gutter trough and then far enough away from the building’s foundation to prevent excessive erosion. Without a downspout, a gutter would merely collect water until it overflowed, or if a drain hole were still in it, a concentrated stream of water would fall directly onto the foundation.
How Downspouts Move Water Away
Each gutter trough is tilted at a slight angle so that it will drain at one or both corners, where a drain hole is cut and a downspout is attached. The exception to this is when short gutter pieces simply connect via inside and outside corners and wind their way around the building to a larger gutter.
Another variable occurs when the angled elbow piece, which connects the gutter to the downspout, bends around the corner to the next wall. In that case, the downspout will be attached there. This “wall switching” is done for reasons such as the following:
- To keep extenders out of a high-traffic lawn area
- To utilize a downward slope for easier drainage
- To hide the downspout from easy public view
Once the water reaches the drain hole, it will simply pour down through the downspout to ground level. If the wall is high enough, multiple downspouts will need to be connected to reach from roof to ground. Each upper spout must go inside of the one below it, not the reverse, or a leak is likely to occur.
Some downspouts simply use a splash block to direct the water a short distance away, but most use extenders. These extenders must screwed to the main spout, angle downwards, and be low enough to the ground to avoid being picked up by the wind. Water exiting the end of the extender will simply soak into the ground or run downhill. Other water-control methods include: flexible PVC extenders, underground drainage pipes that run into a sewer, and downspout-attached water reservoirs.
Types of Downspouts
There are many varieties of downspouts; most are either rectangular or circular. Common materials include:
- Steel, which is very strong but could eventually rust
- Aluminum, which will not rust but could dent or bend
- Copper, which avoids denting and rusting but is very expensive
The maximum volume of water likely to ever travel in the gutter system determines the size of downspout needed. That is, a wider downspout will drain the gutters faster and prevent back-up and overflow during a sudden, heavy downpour.
Of course, one can get downspouts of a myriad of styles as well. Most often, the color will match the wall, but it occasionally matches the corner post or the gutters. The ridges in most aluminum downspouts, while adding a stylistic touch, function to reinforce the strength of the material.
How Are Downspouts Securely Attached?
At the gutter, a metal insert will fit tightly into the drain hole. This insert is then caulked around the edges, and the downspout is screwed to it just below the gutter. Alternatively, flaps of gutter metal can be bent down at the drain hole’s edges. The downspout will then be screwed to the flaps.
Downspouts attached to each other on a tall wall are screwed together. Intermittent straps are wrapped around the spouts, and a screw attaches the spouts to the straps and the straps to the wall. If the wall is stone or brick, drilling may be necessary, but it is relatively easy to screw through siding and corner posts.
What About Cleaning and Repairing Downspouts?
Gutterglove gutter guards are able to keep debris out of a downspout, but if you do not have them and a downspout does get clogged, a hose may be enough to clean it out. Anything that water carried in, water can carry out. For best results, one should use a fixture to shoot water in at high pressure and at different angles.
Extenders often get stepped on, kicked, or blown away. Thankfully, these are easy enough to replace. If a downspout is loose, leaking, or badly dented, it may be best to call in a professional to handle the repair, however.
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