Friday, November 21st

Chapter 3 Index

The exterior - keeping the rain and pests out

Exterior material and craftsmanship failures generally create the most expensive repair problems on our homes. Anyone faced with a multitude of home repairs and maintenance should develop a priority list beginning with the areas of greatest threat. Always attend to inadequacies in the roof, foundation, grade, drainage, and structure before beginning cosmetic repairs. The following sections briefly discuss some of the most common maintenance and repair projects that you'll encounter.

 

Asphalt/fiberglass roofs

 

 

A good roof is the first line of defense against damage and deterioration to your home. Roof leaks damage interior finishes, deteriorate structural members, and attract harmful insects. Among the various types of residential roofs, asphalt or asphalt/fiberglass roofs are the most common and affordable.

Asphalt roofs usually last from 20 to 30 years, depending on the quality of shingle. If you have an asphalt roof, there are several indicators that signal trouble. Loose or cracked shingles, loss of aggregate, loose nails, deteriorated flashing, lumpy surfaces, moss, and asphalt patches are indications that an asphalt roof might need replacing.

When choosing a new roof, always buy the highest quality materials you can afford. The extra money spent on a 30-year shingle as compared to a cheaper product will come back to you many times in the added life of the better roof. Roofing is hard work; if you are installing it yourself, purchase your shingles from a supplier that will deliver them to your roof; you'll be glad you did.

Roofing is best done in moderate weather. Walking and working on an asphalt roof in hot weather can ruin shingles and take years off their expected life. The shingles of roofs applied in frigid weather may not adhere properly and get damaged before the next warm season.

Your choice of color is personal, but there are a few things you should consider. White or light gray roofs often stain easily, especially if there are overhanging trees. Black roofs often appear too monochromatic-like a dark void on the top of the house. Bright red or green roofs might complement your current paint scheme but may be very difficult to work with in your future plans. Several manufacturers are offering shingles that are shaded to resemble the thick profile of slate. Some of these look terrible, so it's a good idea to look at a finished example before choosing them for your home.

If you know what the original roofing material was, you might try to match it in color or shading. For example, many varieties of shingles come in a brown/gray color that is similar to a faded wood shingle roof. You might choose a charcoal gray or gray/green shingle if your roof was once slate. Neutral colors are always easier to work with when choosing a new paint color.

A new asphalt roof will last longest and look best when applied directly over the decking and a layer of roofing felt rather than over multiple layers of old roofs. While it is common practice to apply two or three roofs back to back, two should be the limit, and any more than three could damage your rafters and framing.

Removing the old shingles down to the deck is known in the roofing trade as a "tear-off." When a tear-off is necessary, many homeowners discover that their original roof was applied over spaced or skipped sheathing-boards spaced a few inches apart to allow ventilation of the original wood shingles. In this case, cover the entire roof with a new deck of 5/8" plywood (not particle board) to create a smooth surface for the new asphalt roof. As a cost-saving measure, your roofer might suggest removing only one or two of the old roof layers rather than a complete tear-off. When faced with this decision, always ask for a comparison price between this option and a complete tear-off. Remember, however, the life of the roof over smooth decking will be greater than that of a roof applied over old, uneven shingles.

Manufacturer's recommendations vary, but most asphalt roofs are applied over 15-or 30-pound felt underlayment (tarpaper). Flashing around chimneys, penetrations, valleys, or dormers must be evaluated and replaced with flashing that will exceed the life of the new roof and at least one additional roof. Replace any flashing that has been repaired with asphalt patching compound. Refer to the next section in this chapter for more information about flashing.

Installation of metal drip flashing is a good idea to protect the edge of the roof decking and facia. If ice dams are a problem, install an ice and water membrane. Proper attic ventilation is also important in getting good service from your new roof. Inadequate ventilation might void the manufacturer's warranty, so be sure to read and follow the instructions that are included with the shingles or printed on each bundle. For more information on ice dams and attic ventilation, refer to Chapter 6.

 

Specialty roofs

Specialty roofs Slate, tile, wood-shingle, or metal roofs are often an important feature that substantially contribute to the appearance of your home. Most of these roofs require more expertise than what is needed to apply asphalt shingles. Inexperienced contractors might encourage you to remove or cover a roof that is superior to a new asphalt roof when careful repairs by an experienced professional might be more economical. Always seek roofing contractors who specialize in your type of roof, and get other opinions if your contractor's recommendations seem questionable or unreasonably negative. Other roofs that might require a professional evaluation are concrete-tile, asbestos-shingle, membrane, and built-up systems.

SLATE: Most slate roofs last 50 to 100 years. Generally, the slate does not fail, but the fasteners holding the slate or the flashing under the slate fails. Slate is also damaged by walking on it. Several local roofers maintain a collection of the various types and colors of slate. Repairs are made by pulling the damaged slate out with a shingle or slate ripper and then fastening the new slate in place with copper clips.

TILE: Like slate, tile roofs last from 50 to 100 years, and most failures are related to the flashing and walking on the tiles rather than from the tiles themselves. Repairs must be made by a specialist who maintains a collection of replacements. If salvaged tiles are not available, there are a few suppliers who will make new tiles to match the old ones.

CONCRETE TILE: During the early part of this century, concrete-tile roofs, imitating more expensive tiles, were popular in Rochester for new homes and for replacement roofs. These roofs lost their red color over the years and also became brittle and porous. If you have a concrete tile-roof, there are several contractors who repair them with salvaged tiles. 50-75 years is about all the life you should expect from one of these roofs.

METAL: Repair metal roofs with the appropriate mix of solder and the same type of metal that the roof is made of, i.e. copper to copper. Once a metal roof is coated with bituminous or other coatings, proper repairs are nearly impossible. Any coatings or patching compounds are a temporary fix.

WOOD SHINGLES: Keep wood-shingle roofs clear of debris, leaves, and moss that might prevent adequate drying of the surface. Attic ventilation is especially important to prolong the life of the shingles. The Cedar Shake and Shingle Bureau recommends a periodic treatment of roofs with a fungicidal wood preservative beginning after your new roof weathers for one year. Reapply the preservative every three or four years thereafter.

ASBESTOS SHINGLES: Asbestos shingles were popular for the first 30 years of this century. They were extremely durable, but pose special problems today. As the owner of a single family home, you may remove and dispose of your asbestos-shingle roof, but any contractor that repairs or removes your roof must follow all legal abatement procedures. For more information about proper abatement, call the City of Rochester's Community Development Department at 428-6903 and ask for their asbestos abatement pamphlet.

 

Flashing

 

Flashing is the material used to prevent water penetration into areas of your roof that are difficult or impossible to protect with the roofing itself. In residential construction, the most common areas to apply flashing are around penetrations such as chimneys, dormers, and ventilation stacks; at the intersection of additions, porches, and bays; and at the junction of the roof and parapet walls.

Whenever a roof is covered or replaced, the condition of existing flashing must be evaluated. The decision to leave or replace flashing should include the present condition of the material and the potential of the flashing to last as long as the new roof and possibly an additional roof that might be installed over this one. Flashing installed with a new roof is simple but replacing flashing under an existing roof without damaging the shingles is difficult.

Various metals are used for flashing. Copper, terne, stainless steel, galvanized steel, aluminum, and lead are all used to some degree. For most simple residential applications, labor is the greatest expense of a flashing project. Considering the high cost of labor and the difficulty of installing flashing properly, it's always best to use the best material you can afford.

Copper is one of the most dependable metals used for flashing. When installed correctly, a 50-year life is common. Lead-coated copper is a good choice if the green patina of copper is objectionable, for example, over limestone or any light-colored material that could stain. Copper flashings must be attached with copper nails or clips to avoid galvanic corrosion, a reaction between unlike metals that undermines one or both of the connected materials. Bituminous coatings hasten deterioration of the metal. Therefore, well-intentioned asphalt cement patches often lead to premature failure of the flashing.

Galvanized steel is an acceptable flashing material with a shorter life expectancy, but requires special consideration and maintenance. For example, the acids in cedar shakes and shingles rapidly deteriorate the galvanized (zinc) coating on steel flashing. A properly applied coat of paint, maintained throughout the life of the roof, usually prevents this deterioration. As with copper, bituminous coatings can attack the galvanized protective layer.

Aluminum may be the most commonly used flashing metal for 15-20 year asphalt and fiberglass shingle roof applications. Available in light-weight coils and in prefabricated pieces, it is inexpensive and simple to fabricate without bulky, expensive tools. Aluminum's flexibility also means that it can be torn, penetrated, or twisted out of shape easily. Generally, it should be replaced with each new roof.

STEP FLASHING: Many applications of flashing are simple and straight-forward, others are more complicated. "Step flashing," as applied to masonry surfaces is a difficult technique that is often done wrong. When installed into masonry, properly applied step flashing consists of two parts-the base and the counter flashing (sometimes called cap flashing). Using this system, the two joined areas can move independently without the risk of damage that might occur in a one-piece installation. Smaller stepped pieces of flashing alleviate contraction/expansion stress failures. For maximum protection, all stepped counter flashing should be tucked into a groove (reglet) provided by the mason. This groove can be scored into wet mortar or sawn into old mortar joints.

CRICKETS: Another important type of flashing in this climate is the cricket. Crickets are installed behind chimneys and other larger elements that protrude from or intersect a pitched roof. This is especially useful to deflect snow that might pile up behind a chimney or wall.

VALLEY FLASHING: Valley flashing is used at the intersection of two roof planes. This type of flashing varies according to the individual house. On asphalt roofs, the valley flashing is often omitted in lieu of lapped shingles or a rolled mineral roofing valley. In either case, apply metal flashing under the asphalt material, because the valley always deteriorates more quickly than the adjacent field of shingles, and it's difficult to repair the valley without harming affected shingles. Depending on the details of your house, various types of flashing can be used. If you have a particular problem, refer to the flashing sections of Architectural Graphic Standards.

 

Gutters

If you want to dry out your damp basement and control excessive moisture around your house, a good gutter system is often the first place to begin. Properly installed gutters divert rain and melting snow away from the foundation and also protect your windows, porches, and siding from excessive moisture. Foundation repointing, painting, and carpentry repairs should all come after the gutters are installed.



If you live in a house built at the beginning of this century or earlier, you might have built-in or Yankee gutters. These systems were discretely built into your roof and cornice system, unlike conspicuous hung gutters. It is extremely important to maintain these systems in perfect order. Minor leaks can damage walls, ceilings, and structural members with little indication that expensive repairs are necessary. If you have had problems with your built-in gutters, consider covering them with the roof and installing a more economical, reliable hung-gutter system.

  

There are various types of hung gutters. The most appropriate hung system for most 19th-century and early 20th-century homes is the half-round. Various widths of half-round gutters are available in copper, galvanized steel, and aluminum in 10-, 20-, and 30-foot lengths. Copper gutters with soldered joints are the longest lasting, but galvanized steel half-rounds with soldered joints are more common and economical. Aluminum half-round gutters have an appropriate appearance, but should not be used on houses with seasonal ice dam problems or in situations where they could be crushed by tree limbs or ladders. Aluminum sections are riveted and waterproofed with special sealants.

K-style gutters have an ogee profile (a reverse curve or s shape) similar to the profile found on some early cornice boards. They are most appropriate for houses built after 1940. Like half-rounds, they are also available in copper, galvanized steel, and aluminum. The aluminum seamless gutter is probably the most popular K-style system used today. Seamless gutters are fabricated from large rolls of aluminum to specifically fit your house. Long runs of gutter can be fabricated without troublesome junctions. Unless exceptionally well installed with adequate stiffeners, they are vulnerable to ice-dam, ladder, and tree-limb damage. Lengths over 30 feet must have expansion joints. The metal used for aluminum gutters should be at least .032 inches thick. The aluminum gutters sold at most home centers are .024 inches thick, thus vulnerable to damage.

VINYL GUTTERS: Vinyl gutter systems are the newest type available from hardware and home stores. These are simple to install, but aesthetically inappropriate for older homes and may be a poor choice for our cold climate. Vinyl becomes brittle in cold temperatures and fractures easily.

GUTTER HANGING TIPS:

It's best to replace or repair gutters at the same time you reroof. Fasten hung gutters from adjustable brackets or straps attached to the facia or to the roof deck under the roofing material. Do not use spike and ferrule fasteners; they often loosen after a long winter of cold and snow, and the spike hole at the back can leak, causing facia or rafter deterioration. Never attach gutter straps over shingles; the nail penetrations will eventually leak. To prevent galvanic corrosion, never combine unlike metals; use copper fasteners with copper systems, galvanized nails with galvanized systems, and aluminum with aluminum. Choose gutter widths according to the area being drained and the pitch of your roof; a five-or six-inch width is generally adequate for residences in this area, but steep expansive roofs might require more drainage. Install gutters with a slight pitch toward the nearest downspout. Typically, 1/16 inch per foot is adequate, but long runs look better drained in two directions. Install gutters below the roof plane so that heavy accumulations of snow and ice will slide over the gutter and not into it. Put basket strainers in the downspout openings to prevent leaves from clogging the leaders and drains. Always check the slope with a can of water before paying your installer or before completely fastening the system down. For more specific leader and gutter requirements, refer to Architectural Graphic Standards.

PAINTING GUTTERS: Leave galvanized gutters unpainted or allow them to weather for a year before painting. If they must be painted immediately, remove packing oils with mineral spirits or lacquer thinner and use a galvanized gutter primer, or etch and paint with a quality acrylic latex paint. Aluminum gutters come with a factory finish. Copper gutters are usually allowed to weather into an attractive green patina. To maintain your gutters, remove debris, clean basket strainers, and inspect for leaks and proper drainage yearly. If your gutter system is not connected into the local storm sewer or dry well, install splash blocks to divert water away from your foundation.

 

Grade and foundations

One of the most common site problems for homeowners is an inadequate grade or level of earth around your house. If your house site is lower than the yard around it, any rain or snow melt has no option but to percolate directly down your foundation wall, creating a musty or wet basement. This condition didn't exist when your house was new. Grass clippings, leaves, plantings, and added topsoil all build up over time, increasing the grade of your yard by as much as one foot in 100 years. Poorly planned driveways, sidewalks, and additions often exacerbate the problem. This means that a house designed to sit atop a slight rise or hill might now be sitting in a depression.

Maintaining or restoring an appropriate grade should be central to any landscaping plan. Ideally, the earth around your house should slope away from it. Remove dense bushes or plantings adjacent to the foundation. These hold moisture next to your house and often create a damp environment next to vulnerable building materials. Where possible, raise the grade by adding topsoil. Your sills and clapboards must be at least eight inches from the ground; if adding soil raises the earth too close to these vulnerable elements, regrade troublesome locations by removing soil and installing underground drains or swales to create better drainage.

The foundation of your house must be maintained from the inside and out if the rest of the structure is expected to function correctly and remain stable. A deteriorated foundation can create minor annoyances like sticking doors or windows, or it can lead to devastating problems such as bowed walls, sagging rooflines, and structural failure.

Most older houses in this area have stone or concrete block foundations. If you have a brick foundation, it is probably veneer over stone or block, because bricks are porous and deteriorate easily. In many neighborhoods, decorative or rock-faced concrete blocks were used above grade over stone footings.

MOISTURE AND YOUR FOUNDATION: Rising damp is moisture that is absorbed into porous masonry materials and rises up a wall through the capillaries in these materials. It can creep several feet up a wall. When this moisture freezes and the surface of the masonry breaks off in small pieces, hunks, or paper-thin flakes, the condition is known as spalling. Spalling can occur from any source of moisture such as leaky roofs or missing copings.

Another sign of a moisture problem is efflorescence, a white salt-like crystalline deposit that is often noticeable on basement walls, foundations, and exterior masonry walls. Efflorescence is composed of soluble salts that are dissolved in the mortar and brought to the surface. Like spalling, these salts can damage your foundation as they expand and grow. Small particles or larger chunks of masonry can gradually break loose from the foundation until major repairs are needed.

If you have moist conditions around your house-puddles of water, a musty basement or mildew on the walls-but no sign of spalling or efflorescence, you still should be concerned. Constant wetness can dissolve the particles that hold masonry units together whether the masonry is concrete, sandstone, or brick.

Always stop the source of moisture before repairing and repointing damaged masonry. Adjusting the grade to slope away from the foundation and installing a good gutter system are good ways to begin.

TREES AND YOUR FOUNDATION: Don't plant saplings too close to your house. Strong foundations are sometimes damaged by small roots that entered tiny cracks, then grew and expanded the crack. Large roots can push bulges into the foundation wall. Excavate problem tree roots, or remove the entire tree before making repairs or repointing.

REPOINTING YOUR FOUNDATION: The mortar chosen for repointing is one of the least understood yet most important details in repairing masonry. Through most of the 19th century, masons used lime mortar. This slow-drying, soft mortar was compatible with the stone used for most foundations. Near the turn of the century, masons added Portland cement to the lime to make a harder mortar for the cast concrete blocks that were popularly replacing stone. In each case, the mortar was always softer than the adjacent masonry units. Slow-drying, soft beds of lime or lime/Portland mortar allowed buildings to settle initially and adjust to the contraction/expansion rigors of this climate. Lime and lime/Portland mixes are still appropriate for repointing. Hard Portland mortar was not used historically and cannot successfully be used today. Mortar that is harder than adjacent stone, brick, or block will crack, allowing moisture penetration and increasing the chance of spalling. If the mortar fails, it cannot be removed safely from the masonry where it is firmly attached. Finally, beware of inexperienced contractors who urge you to cover your foundation with stucco. Stucco (sometimes called parging) is not a substitute for repointing and repairs; it often covers up the problem rather than actually remedying it. For more specific repointing instructions, refer to Chapter 4.

 

Wet basements

Wet basements Damp or wet basements are usually cured by improving the drainage around your house. A sloping grade and functioning gutters solve most problems. If you've noticed specific damp areas, check to see if these areas correspond with an interior or exterior drainage pipe that joins the storm sewer. If these pipes are clogged with roots or collapsed, the water will back up, possibly into your basement. Your plumber can clean these lines or tell you if they must be replaced. In plumber lingo, this is known as "snaking the lines." Many foundation windows are below grade and protected by window wells. When these wells are not cared for, moisture is often forced through the window or the wall below it. Excavate window wells allowing at least 8" of clearance below the window sill and another 8" of gravel for drainage. For problem basements not dried out by typical drainage measures, contractors sometimes recommend excavating the foundation, applying a waterproof coating, and installing a gravel drain system leading away from the house. Consult an architect or professional engineer before undertaking such a drastic project. Also, be wary of waterproofing companies that recommend interior basement perimeter drains and a sump system without addressing your gutters and grade. Interior perimeter drains and sumps treat the symptoms but not the problem. You'll still have open water in your basement, thus the possibility of a musty odor and excessive humidity.

 

Rot, insect damage and infestation

Rot, mold, mildew, carpenter ants, termites, and wood-boring beetles are all attracted to damp environments, and they can all be avoided. Knowing how and where to detect them is the first step in eradication.

ROT/FUNGI: There are many types of rot, and they all have one thing in common: rot does not occur without, first, the presence of excessive moisture and, second, the presence of fungus spores. If you discover rot, the source of moisture must be stopped before making repairs. Many people are confused by the term "dry rot"; after all, how can something rot if it's dry? The reason is that the rotted area was once wet or suffered from seasonal wet and dry periods.

CARPENTER ANTS:

Carpenter ants are large (1/4"-1/2") and black with a thin pinched waist between the thorax and abdomen. They are most often noticed in the spring. If you detect carpenter ants inside or around your house, inspect it for a damp area where they might be burrowing. The logical areas of infestation are the foundation, woodpiles, and porches. But don't rule out unlikely places like the deck under a leaky roof, interior walls around faulty plumbing, or sills moist from wall condensation. Carpenter ants are also commonly found around deteriorating and rotten tree stumps. If this is the case in your yard, get rid of them before they find some vulnerable area of your house. Carpenter ants can be controlled with insecticides, but it is most important to stop the source of moisture first. For safe insecticides that you can use, call the Cornell Cooperative Extension Office, at 461-1000. If you cannot locate the ant colony, call a pest-control professional.

TERMITES:

Termites are not as common in this climate as in warmer regions of the country, but they do exist here, and with virtually no evidence of their presence, can create serious damage to a house. Distinguishing between termites and ants is easy. The termite body does not narrow in the middle like that of an ant; termites also have wings or wing stubs where wings were once attached. Dirt tunnels running from the ground up to the wooden members of your foundation are a good indication that you have termites. Like carpenter ants, termites are also attracted to moist wood. The major difference, however, is that carpenter ants do not eat wood for nourishment and termites do. Since termites often construct tunnels from the earth to a structure, they bring in enough moisture to live and continue their destruction even if there is no excessive moisture problem. Termite damage can be extremely destructive, reaching into all areas of your home. If you have a termite problem, call a professional exterminator.

POWDER-POST BEETLES:

It's rare to inspect the sills and basement joists of a 19th-century home that does not have some degree of beetle damage. Usually they've done their damage and moved on, but it is important to determine if the damage is old or new. Small pyramidal piles of dust (frass) below 1/8" round holes usually indicate their presence. Beetles damage hardwoods and softwoods, but each family of beetle attacks only one or the other. Powder-post beetles commonly infest the sapwood of oak or other hardwood timbers. Since they are often brought into a house in unseasoned timber or firewood, it is important to use only seasoned or treated lumber and keep firewood away from the structure. Excessively damp and humid basements must be ventilated or dehumidified. There are very few chemicals effective on powder-post beetles that are legal for homeowner use. For recommendations, call the Cornell Cooperative Extension Office. In extreme cases, professional fumigation is the best treatment.

INSECTICIDE SAFETY: The pest-control industry has changed drastically over the past few years. The general public and professional exterminators are much more aware of the dangers of toxic chemicals. Many insecticides that were commonly available in the past are no longer legal, and the approved list of chemicals changes constantly. Professional exterminators will provide technical data on any chemicals they propose to use in your house. If your insect problem is pervasive, call a professional exterminator. If your problem is minor, the Cornell Cooperative Extension Office (461-1000) will send you up-to-date information on available chemicals. Many professional pest-control companies encourage new customers to begin routine inspections and applications. This is generally unnecessary if all moisture problems are solved and the initial extermination process is successful.

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