B E R O A R C H I T E C T U R E P L L C

A R C H I T E C T U R E S U S T A I N A B I L I T Y P R E S E R V A T I O N

Thirty Two Winthrop Street, Rochester, New York 14607
585-262-2035 (phone) •  585-262-2054 (fax) • contact@beroarchitecture.com (email) 

SOME THOUGHTS ON RAINWATER MANAGEMENT

Rainwater management is an important part of a building’s protective umbrella. Proper management extends the life of the foundation, discourages wood boring insects and rot, and creates a healthy environment for both people and building materials. Proper rainwater management and adequate ventilation will help keep basements dry and free of mold, mildew, and other potentially health threatening organisms. Rainwater management has three aspects: collection, disposal, and site grading. Maintenance is an important component of each aspect.

COLLECTION 

Built-in Gutters

Built-in gutters are usually found on high style homes or institutional buildings where the appearance of hung gutters is undesirable. Built-in systems are usually well designed and constructed. However, they require the same yearly maintenance as hung gutters and receive it just as infrequently. Since built-in gutters are part of a building’s structure, they must be carefully maintained. Minor leaks can damage walls, ceilings, and structural components with little indication that damage is occurring and expensive repairs are necessary. For these reasons, built-in gutters are more likely to contribute to the loss of historic building details and building structure than hung gutters; we are hesitant to recommend built-ins.

Hung Gutters

We recommend either copper or galvanized steel half-round hung gutters with soldered joints. They are historically appropriate, more durable than aluminum gutters, and less likely to cause damage to the building structure if they leak than built-in gutters. When properly installed, steel or copper gutters will bear the weight of ladders without denting and withstand the rigors of heavy snow loads and ice damming. Both metals can be joined by soldering; the popular aluminum gutters and downspouts must be sealed with caulking which has a relatively short life compared to solder. Aluminum K-style gutters are often installed with spike and ferrule fasteners. Do not use this hanging system for gutters of any style or metal. The spike pierces the gutter below the high water line allowing leaks that cause the cornice and rafter tails to rot and the spike to loosen. The cost savings available by using aluminum gutters is achieved by using lower quality materials and installation techniques that provide reduced performance and durability.

Hangers should be attached without fastening through the roofing and spaced closely enough (16" on center, maximum) to resist snow loading and ice build-up. All straps, downspouts, fasteners, and other components in contact with one another must be the same metal (i.e. galvanized to galvanized, copper to copper) to prevent galvanic corrosion, deterioration at the contact point of dissimilar metals subject to wet conditions. New gutters and downspouts should be correctly sized and installed to meet the square footage and slope requirements of the roof.

Downspouts should drop with as few horizontal runs as possible. These are both unsightly and cause maintenance problems. Strainers should be installed at gutter outlets to help protect downspouts; leaves and debris are easier to clean from a gutter than when packed into the length of a downspout. New downspouts should be corrugated galvanized or copper with the back seam soldered. Downspouts should not be permanently connected (riveted, screwed, or soldered) to the gutters but should be loosely connected to the outlet leader or connected with a conductor head to allow vertical contraction and expansion of the downspout. Downspouts should be supported by wall brackets, not by hanging from the gutter.

DISPOSAL

Once the water is collected and led to grade it can be dumped on the ground or into an underground disposal system. The least attractive of these alternatives is to dump it on the ground. If there is no other alternative, a substantial (preferably precast concrete) splashblock should be positioned under a discharge elbow and properly pitched and aimed to get the water as far from the foundation as possible. This system usually fails after a brief time due to settlement of the grade, removal of splashblocks for lawn mowing, or any number of other reasons. Unless there is constant attention to splashblock placement, water usually finds its way into the foundation or crawl space, violating the aim of the stormwater collection system. The best means of stormwater disposal is into your municipal storm sewer or into underground piping run to daylight on the property. At the transition point from downspout to underground piping, a cast iron clean-out “T” must be used for access and durability. These are more expensive than PVC fittings, but PVC does not stand up to ultraviolet light or impact by lawn mowers.

SITE GRADING

Over time the soil tends to settle near the foundation creating a grade that is neutral or sloped toward the building. Beneath eaves without benefit of gutters a trough develops that collects water at or near the foundation. Where splashblocks or downspouts have failed, large quantities of water are concentrated at points along the foundation creating depressions and ponding. Depressed areas also form around the base of large or old foundation plants. Water collected in these low areas will eventually find its way into the basement. Compacted soil sloped away from the foundation at a gradient of one half-inch per foot over ten feet or more is generally adequate. Basement windows may require wells to accommodate the grade and keep their wooden components dry.

MAINTENANCE

Ongoing maintenance is required of any gutter system. If an owner waits for physical signs of system failure to appear on the building fabric, unnecessary damage will occur. Gutters need to be cleaned and inspected at least once a year. Take the time to: remove any debris; make sure all components are in place after the mowing season; inspect all gutters, downspouts, and disposal systems; and repair damage.