How long do slate roof tiles last

Knowing which materials provide the longest lifespan can also help you make the best choice for roofing when you need to get a new one installed. Asphalt is used to make roofing shingles and is a common roofing material as it is very affordable and easy to install.

Asphalt roofing shingles are made from either paper fibre mat or fibreglass that has been impregnated with asphalt and coated with mineral granules. These shingles can be expected to last from around 15 to 40 years, depending on the quality of materials chosen, the installation and the environment the roof is exposed to.

You can maximise the lifespan of asphalt shingles by avoiding cheap shingles and keeping them clear of debris where possible.

Metal roofing is a common option found in commercial, industrial, and agricultural buildings, but can also be used for housing. They are popular in areas prone to wildfire danger due to their resistance to fire damage. Metal roofing often takes the form of roofing sheets that is laid in panels with the seams overlapping along the roof slope. These types of roofs are easy to maintain and are very durable against the elements.

They have a lifespan of around 30 to 50 years, which puts it far ahead of asphalt shingles, although some homes may not be suitable for metal roofing.

Traditional tiles are made from terracotta clay, but you can also get ceramic tiles made of fired clay. The most economically important slate deposits in this country lie in the Mid-Atlantic and Northeastern states transversed by or bordering on the Appalachian Mountain chain. Variations in local chemistry and conditions under which the slate was formed have produced a wide range of colors and qualities and ultimately determine the character of the slate found in these areas.

Slate is available in a variety of colors. The most common are grey, blue-grey, black, various shades of green, deep purple, brick red, and mottled varieties. The presence of carbonaceous matter, derived from the decay of marine organisms on ancient sea floors, gives rise to the black colored slates.

Compounds of iron generate the red, purple, and green colored slates. Those of Virginia have a distinctive lustrous appearance as well due to their high mica content. The slates of Lehigh and Northampton Counties, Pennsylvania, are grayish-black in color.

Green, red, purple, and mottled slates derive from the New York-Vermont district. The slate producing region of New York, which centers around Granville and Middle Granville, is particularly important because it contains one of the few commercial deposits of red slate in the world. Slates are also classified as fading or unfading according to their color stability.

Fading slates change to new shades or may streak within a short time after exposure to the atmosphere due to the presence of finegrained disseminated pyrite. For example, the "weathering green" or "seagreen" slates of New York and Vermont are grayish green when freshly quarried. Slates designated as unfading maintain their original colors for many years. Color permanence generally provides no indication of the durability of slate.

Rather, time has shown that the Vermont and New York slates will last about years; Buckingham Virginia slates years or more; and Pennsylvania SoftVein slates in excess of 60 years; Pennsylvania HardVein slates and Peach Bottom slates, neither of which is still quarried, had life spans of roughly and at least years respectively. The life spans provided should be used only as a general guide in determining whether or not an existing slate roof is nearing the end of its serviceable life.

Ribbons are visible as bands on the cleavage face of slate and represent geologic periods during which greater amounts of carbonaceous matter, calcite, or coarse quartz particles were present in the sediment from which the slate was formed.

Ribbons typically weather more and were most common in Pennsylvania slate quarries. As they were not as durable as clear slates, ribbon slate is no longer manufactured for roofing purposes. Mottled grey slates from Vermont are the closest match for Pennsylvania ribbon slate available today. In recent years, slates from China, Africa, Spain and other countries have begun to be imported into the United States, primarily for distribution on the West Coast.

The use of imported slates should probably be limited to new construction since their colors and textures often do not match those of U. The white blotches on these Pennsylvania Soft-Vein slates indicate areas where gypsum is leaching out onto the surfaces of the slates.

The durability of a slate roof depends primarily on four factors: the physical and mineralogical properties of the slate; the way in which it is fabricated; installation techniques employed; and, regular and timely maintenance.

The first three of these factors are examined below. The maintenance and repair of slate roofs are discussed in later sections of this Brief. The natural weathering of roofing slate manifests itself as a slow process of chipping and scaling along the cleavage planes. Paper thin laminations flake off the surface of the slate and the slate becomes soft and spongy as the inner layers begin to come apart, or delaminate. The nature of the sound given off by a slate when tapped with one's knuckles or slating hammer is a fair indication of its condition.

Highgrade slate, when poised upon the fingertips and struck, will emit a clear, solid sound. Severely weathered slates are much less sonorous, and give off a dull thud when tapped. Because gypsum molecules take up about twice as much volume as calcite molecules, internal stresses result from the reaction, causing the slate to delaminate.

This type of deterioration is as prominent on the underside of the roof as on the exposed surface due to the leaching and subsequent concentration of gypsum in this area.

Consequently, deteriorated roofing slates typically cannot be flipped over and reused. Paper thin lamination can be seen flaking off this weathered, year piece of Pennsylvania Hard-Vein slate. The chemical and physical changes which accompany slate weathering cause an increase in absorption and a decrease in both strength and toughness. The tendency of old, weathered slates to absorb and hold moisture can lead to rot in underlying areas of wood sheathing. Such rot can go undetected for long periods of time since, often, there is no accompanying leak.

Due to their loss of strength, weathered slates are more prone to breakage, loss of corners, and cracking. Slates with low calcite content tend to weather slowly.

Dense slates, with low porosity, likewise decay slower than slates with equal calcite, but with a greater porosity. The pitch of a roof can also affect its longevity. The steeper the pitch, the longer the slate can be expected to last as water will run off faster and will be less likely to be drawn under the slates by capillary action or driven under by wind forces.

Spires and the steep slopes of Mansard roofs often retain their original slate long after other portions of the roof have been replaced. Areas of a roof subject to concentrated water flows and ice damming, such as along eaves and valleys, also tend to deteriorate more rapidly than other areas of the roof.

View of these slates laid on open sheathing shows that delamination and flaking are just as bad or worse on the underside of slates as on the exposed surface.

This is why most slates cannot be flipped over for reuse. Mechanical agents, such as thermal expansion and contraction and the action of frost, are subordinate in the weathering of slate, coming into play only after the slate has been materially altered from its original state by the chemical transformation of calcite to gypsum. The more rapid deterioration of slates found on roof slopes with the most severe exposure to the sun, wind, and rain typically, but not always, a southern exposure may be attributable to the combined result of the deleterious effects of impurities in the slate and mechanical agents.

Atmospheric acids produce only negligible deterioration in roofing slate. It is difficult to assess the procedures by which a piece of slate has been fabricated without visiting the quarry and observing the process first hand. The location and size of nail holes, grain orientation, the condition of corners, and the number of broken pieces are all things which may be observed in a shipment of slate to judge the quality of its fabrication.

Nail holes should be clean and with a shallow countersink on the face of the slate for the nail head; grain oriented along the length of the slate; and, corners left whole.

Installation problems often involve the improper nailing and lapping of slates. The nailing of slates differs from that of other roofing materials. Slate nails should not be driven tight as is the case with asphalt and wood shingles.

Rather, they should be set such that the slate is permitted to hang freely on the nail shank. Nails driven too far will crack the slate and those left projecting will puncture the overlying slate. Nail heads left exposed accelerate roof deterioration by providing a point for water entry. Non-ferrous slater's nails, such as solid copper or stainless steel, should always be used since plain steel and galvanized nails will usually rust out long before the slate itself begins to deteriorate.

The rusting of nineteenth century cut nails is a common cause of slate loss on historic roofs. When joints are improperly broken i. Insufficient headlap can also result in leaks as water entering the joints between slates may have a greater tendency to be wind blown beyond the heads of the slates in the course below.

Occasionally, individual slates are damaged. This may be caused by falling tree limbs, ice dams in gutters, valleys, and chimney crickets, the weight of a workman walking on the roof, or a naturally occurring fault in the slate unit. Whatever the form of damage, if it is caught soon enough, the roof can usually be repaired or selectively replaced and deterioration mitigated.

The ability to lay slate properly so as to produce a watertight and aesthetically pleasing roof requires training, much practice, and the right tools. The installation and repair of slate roofs should be entrusted only to experienced slaters.

Broken, cracked, and missing slates should be repaired promptly by an experienced slater in order to prevent water damage to interior finishes, accelerated deterioration of the roof and roof sheathing, and possible structural degradation to framing members.

The damaged slate is first removed by cutting or pulling out its nails with a ripper. If steel cut nails, rather than copper nails, were used in laying the roof, adjacent slates may be inadvertently damaged or displaced in the ripping process, and these, too, will have to be repaired. If the slate does not slide out by itself, the pointed end of the ,slate hammer can be punched into the slate and the slate dragged out.

A new slate, or salvaged slate, which should match the size, shape, texture, and weathered color of the old slate, is then slid into place and held in position by one nail inserted through the vertical joint between the slates in the course above and approximately one inch below the tail of the slate two courses above.

After removing the deteriorated slate and sliding the new slate into place, it is secured with a copper nail. A copper bib shown here is formed to protect the newly created nail hole. Finally, a slate hammer is used to push the bib in place over the nail head. To prevent water penetration through the newly created nail hole, a piece of copper with a friction fit, measuring roughly 3" 7.

Alternate methods for securing the replacement slate include the use of metal hooks, clips, and straps that are bent over the tail end of the slate.

The application of roofing mastic or sealants to damaged slates should not be considered a viable repair alternative because these materials, though effective at first, will eventually harden and crack, thereby allowing water to enter. Mastic also makes future repairs more difficult to execute, is unsightly, and, when applied to metal flashings, accelerates their corrosion. When two or more broken slates lie adjacent to each other in the same course, or when replacing leaky valley flashings, it is best to form pyramids i.

When reinstalling the slates, only the top slate in each pyramid will need a bib. Slates along the sides of the pyramid will receive two nails, one above the other, along the upper part of its exposed edge.

When many slates must be removed to effect a repair, the sheathing should be checked for rotted areas and projecting nails. Plywood is generally not a good replacement material for deteriorated wood sheathing due to the relative difficulty of driving a nail through it the bounce produced can loosen adjacent slates. Instead, new wood boards of similar width and thickness to those being replaced should be used. Because the nominal thickness of today's dimension lumber is slightly thinner than that produced in the past, it may be necessary to shim the new wood boards so that they lie flush with the top surface of adjacent existing sheathing boards.

Pressure treated lumber is not recommended due to its tendency to shrink. This can cause the slates to crack and become displaced. To permit proper re-laying of the slate, the new roof sheathing must be of smooth and solid construction.

At least two nails should be placed through the new boards at every rafter and joints between the ends of the boards should occur over rafters.

Insufficient nailing will cause the boards to be springy, making nailing of the slates difficult and causing adjacent slates to loosen in the process.

Unevenness in the sheathing will show in the finished roof surface and may cause premature cracking of the slate. Roof sheathing in valleys and along hips, ridges, and eaves may be covered with waterproof membrane underlayment rather than roofing felt for added protection against leakage. After a hurricane or other natural disaster, it may be necessary to stabilize a roof temporarily until materials can be obtained and a qualified roofing contractor hired.

Significant slate roofs should not be stripped off and replaced with asphalt shingles. In emergency situations, such as when severe hurricanes or tornadoes blow numerous slates off the roof, a temporary roof covering should be installed immediately after the storm to prevent further water damage to the interior of the building and to permit the drying out process to begin.

Heavy gauge plastic and vinyl tarpaulins are often used for this purpose, though they are difficult to secure in place and can be blown off in high winds. Roll roofing, carefully stitched in to areas of the remaining roof, is a somewhat more functional solution that will allow sufficient time to document the existing roof conditions, plan repairs, and order materials.

Slate roof repair is viable for localized problems and damaged roofs with reasonably long serviceable lives remaining. This is especially true of older roofs nearing the end of their serviceable lives because even the most experienced slater will likely damage additional slates while attempting repairs. Depending on the age of the slate, its expected serviceable life, and the cause s of deterioration, it may or may not be cost effective to salvage slates.

Where deteriorated nails or flashings are the cause of the roof failure, salvage of at least some slates should be possible for use in repairs. When salvaging slates, each must be sounded to discover cracks and faults and the degree to which it has weathered. It is usually wise to salvage slates when only a portion of the roof is to be replaced. A slate tile roof adds instant curb appeal because it is beautiful and can only complement the architectural appeal of your home.

However, before you make the decision to use natural slate on your roof, you need to know the pros and cons about slate roofing tiles and what alternative options you have that will give you the look of natural slate tiles without the problems that come with real slate roof tiles. It consists mainly of grains of mica, chlorite, and quartz and may also have calcite, pyrite, hematite, and other minerals.

Most slate is gray to black in color, but the rock may be red or green, depending on its mineral content. Slate is made from the natural compression of clay and other materials under heavy pressure in the earth. This is an organic process, and as the layers build one on top of the other, slabs of different thicknesses are formed. As they are mined, they are sent to where the layers are split and will form the roof tiles used for roofing. The location where the slate was originally quarried will determine the quality of the product that is delivered to your jobsite for installation.

Considering that much of the production is done by hand, there is no way to mechanize a process that continuously produces a consistent and superior roofing tile. Each piece of slate roof tile can be no better than the effort put into producing it. That leaves a lot of room for errors in workmanship and quality control. It is important to find a reliable, experienced roofer with references related to installing real slate tiles.

You will need to consult with the contractor regarding where to purchase the product and their recommendation on what type of slate roof tiles to purchase. You should also visit some of their jobs to see what kind of work they have produced. Installing a slate tile roof requires a tradesperson with years of experience handling the product, prepping the roof, setting up scaffolding in a way that protects the integrity of the tile during installation, cutting and shaping tiles with hand tools for a perfect fit around pipes and other penetrations in the roof, and being familiar with the myriad parts of a typical slate tile roof installation in order to deliver a beautiful, professionally completed roof.

Slate is a hard rock and is known for withstanding the elements when first mined, but over time, without proper maintenance, it can grow soft and break easily.