Technical Procedures Disclaimer
Prior to inclusion in GSA’s library of procedures, documents are reviewed by one or more qualified preservation specialists for general consistency with the Secretary of Interior Standards for rehabilitating historic buildings as understood at the time the procedure is added to the library. All specifications require project-specific editing and professional judgement regarding the applicability of a procedure to a particular building, project or location. References to products and suppliers are to serve as a general guideline and do not constitute a federal endorsement or determination that a product or method is the best or most current alternative, remains available, or is compliant with current environmental regulations and safety standards. The library of procedures is intended to serve as a resource, not a substitute, for specification development by a qualified preservation professional.
We’ve reviewed these procedures for general consistency with federal standards for rehabilitating historic buildings and provide them only as a reference. Specifications should only be applied under the guidance of a qualified preservation professional who can assess the applicability of a procedure to a particular building, project or location. References to products and suppliers serve as general guidelines and do not constitute a federal endorsement nor a determination that a product or method is the best alternative or compliant with current environmental regulations and safety standards.
- This procedure includes guidance on inspecting and maintaining gutters and downspouts.
- Gutters on older structures can cause problems because they are often integrated with the roof structure such as built-in gutters, cornice gutters, hidden gutters and Yankee gutters; and if not properly maintained can result in leaks into roof, cornice, or structure itself. Hung-gutter types are more common onnewer structures.
- A failed gutter often means that damage has spread; repairs will be extensive, maybe complicated, and probably expensive. A well-restored gutter, however, faithfully inspected and maintained, should require no major repairs for some years.
- Downspouts, flashing, conductor heads, leaders, roof drains, and scuppers are all part of the drainage system, and should be included in the work list when maintenance or repairs are being evaluated and scheduled for the gutters.
- Liquid bleach:
CAUTION: DO NOT MIX AMMONIA WITH CHLORINE BLEACHES, A POISONOUS GAS WILL RESULT! DO NOT USE BLEACH ON BIRD DROPPINGS.
- Clean, potable water
- Safety belt or harness
- Ladders and scaffolding
- Chicken ladder
- Garden hose
- Plumbers test plugs to fit the downspout conductor head
- Carpenter's level
- Mason's level
- Chalk line
- Shaped wooden or plastic paddle for scraping and sweeping
- For steep roofs, inspect hanging gutters from ladders. Do not rest ladders on sheet metal gutters. Establish roof foot traffic regulations for inspection of built-in gutters.
- Check for interior deterioration which might point to gutter and/or roof problems.
- Inspect for buildup of debris and vegetation such as moss or lichen. Biological material excretes corrosive acids. This is apt to occur with improper gutter sloping.
- Check for adequate slope and drainage towards downspouts during cleaning.
- Make sure all downspout connections have wire strainers and that they are properly installed. Strainers will block large debris and leaves that can block downspouts and sewer lines.
- Inspect for gutters that are split or cracked with loose, broken, out of place, hangers, corners or slopes, or pulling of fasteners, broken joints or seams; excessive staining or punctures of gutter fabric.
- Inspect joints frequently; Repair cracks immediately.
- Look for corrosion around nails. Roof cement on gutters may hide leaks that have not been corrected.
- Check for deterioration of adjacent roof and soffit areas, and behind downspouts. Look for peeling paint or stains, or eroded mortar joints on adjacent surfaces.
- Inspect the underside of the roof cornices. Water stains may be evidence of ice dams.
- Install soffit ventilators in the cornice. This helps the cornice dry out and wards off rot after the inevitable periodic leaks of water into the woodwork. Ventilators have a drawback, of course, in that by increasing air flow inside the cornice, they also add to heat loss in winter. This can be minimized by proper insulation of attic spaces.
- Any gutter liners made of tin, galvanized iron, or terne metal should be kept painted.
- In addition to scheduled inspections, inspect after each exposure to unusually severe weather conditions such as strong winds, large snowfall, or long continuous rains.
- Examine gutters as a part of the annual roof inspection and repair defects immediately. Have a competent roofer and plumber inspect the fabric and the joints for defects. Small gutter leaks may force water into concealed cornice and roof areas leading to major defects.
- Carry out a professional survey every five years.
- In the Fall, check gutters and clean as necessary once a week from the time the leaves begin to fall until they have all fallen. Monthly inspections are recommended during winter months to insure nothing impedes the flow of water thereby causing an ice dam in freezing weather.
3.02 ERECTION, INSTALLATION, APPLICATION
- Debris removal: Clean gutters of debris at least twice a year especially if surrounded by large trees, in late fall after all leaves have fallen; and in late spring after all seed pods, flowers, etc. have fallen. Clogged leaders can cause water overflow and ice build-up, and any acidic elements at the bottom of a damp trash pile can eat away at the metal liner.
- Sweep debris from gutters with a wood or plastic tool shaped to fit into radii or corners.
- Remove and bag debris such as leaves, pine needles, branches, nests and other litter so that the gutter drains freely.
- Where dirt or leaves lodge or normally collect in the gutters, it is advisable to paint at yearly intervals.
- If debris is blocking downspout, remove a lower section and flush. Do not allow clog to be forced into sewer or drainfield system. Realign the gutters and downspouts.
- Removing Biological Growth:
NOTE: ACTIVE METALS SUCH AS TIN AND COPPER DO NOT SUPPORT BIOLOGICAL GROWTH.
- When moss, lichen, or fungus is present, wipe or scrape off growth. Use a shaped wooden or plastic paddle so as not to scratch the surface of the sheet metal.
- Use a 50/50 solution of liquid bleach and water to saturate and disinfect the areas of biological growth. Brush the disinfectant solution on the gutters. Keep the solution from splashing to avoid damage to other building material and nearby vegetation.
- After disinfectant treatment, scrub and rinse thoroughly.
- When this type of vegetation persists, contact the Regional Historic Preservation Officer (RHPO) for assistance.