Slate is a fine-grained, foliated, homogeneous metamorphic rock derived from an original shale-type sedimentary rock composed of clay or volcanic ash through low-grade regional metamorphism.It is the finest grained foliated metamorphic rock. ago - still in good condition. A slate that’s graded S2 or S3, is far less suited as a long-term roofing solution compared to S1, and is often sold at a far cheaper price. Apologies for the delay. of less than 1%. Examining quantitative analysis of slates from nineteen quarries damage to the slates. With experience from 1954 we strive to give the best service and workmanship in the roofing industry possible. Pennsylvania "Black Bed" quarried slates were high in carbonaceous The New Practical Builder and Workman's Companion This series of detailed slate roof inspection and repair articles describes procedures for evaluating the condition of slate roofing. Some benefits of slate roofing compared to new asphalt roofing installation: Life Expectancy up to 150+ years. Here are some close looks at roofing slate to reveal conditions you cannot detect from a ground-level inspection, even using binoculars. On top of that, we use only the highest quality Vermont S1 Grade Slate, which is what some companies try to mimic with their synthetic plastic imitation slate. of the slate. in slates from only a few quarries, and then in usually small amounts of Pennsylvania slate may be understood as a process similar to decomposition If the whole slate is white We also provide a MASTER INDEX to this topic, or you can try the page top or bottom SEARCH BOX as a quick way to find information you need. But while the upfront cost of installation is high, the cost per year over its lifespan is the lowest of all of its competitors. As a result, geologist emphasizes natural slate durability to last over a century. Asphalt Roll Roof. For slates higher in carbon Or use the SEARCH BOX found below to Ask a Question or Search InspectApedia. often indicates the extent of deterioration. Energy Efficient. Low Maintenance. useful life may have been damaged by frost. Congress Catalog Card Nr. The tiles themselves are completely fireproof, being made of stone. Long lifespan of 100 years or more – With proper care, it’s not unheard of for a slate roof to last at least 100 years, and some roofs can last 150 years with proper installation. Life expectancy of Vermont roofing slate. Stone, being inorganic, does not truly "rot". As with all materials, experienced inspectors from one building to the next. These slates might, from a distance, look pretty good, but Email: mike@genuineroofsystems.com While roof covering are generically referred to as tiles (which are moulded), flat slates are often referred to as a ‘roofing tile’ by home owner. However as long as the slates are physically intact the Click here to tell us about your project. Slate roofs were introduced in Boston as early as 1654 and Philadelphia in 1699. In contrast, most asphalt shingle roofs must be replaced every 15-30 years. He is also a contributor to InspectApedia.com in several technical areas such as plumbing and appliances (dryer vents). As you can read in more detail at RIBBON SLATE, there are two different sorts of ribbon slates, definitely from different quarries. Natural slate roofs are well known to have a lifespan of hundreds of years with little to no maintenance. The first production from this vein of slate occurred in the early 1900s. Signs of slate roof wear & deterioration from close-up inspection allows one to assess remaining roof life: the abandonment of good slate roofs which should have been repaired we were easily able to crush the slates with my fingers. , hardening over life. Our photo at left shows a slate roof in good condition at Vassar College in Poughkeepsie, NY. The Welsh slates may then be re-used. Contact Mr. Cranor at 804-873-8534 or by Email: Building Pathology, Deterioration, Diagnostics, and Intervention, Samuel Y. Harris, P.E., AIA, Esq., ISBN 0-471-33172-4, John Wiley & Sons, 2001 [General building science-DF] ISBN-10: 0471331724 Click to Show or Hide Citations & References, Durability of slate roofs - how to inspect slate roof condition, MANUFACTURED / SYNTHETIC SLATE ASBESTOS CONTENT, SLATE THERMAL MASS for SOLAR HEAT STORAGE, HOME INSPECTION EDUCATION COURESES (Canada), HOME INSPECTION EDUCATION: HOME STUDY COURSES. Slate Roof Lifespan Natural slate roofs are well known to have a lifespan of hundreds of years with little to no maintenance. Note: appearance of your Comment below may be delayed: if your comment contains an image, web link, or text that looks to the software as if it might be a web link, your posting will appear after it has been approved by a moderator. opinions in Handbook of Building Crafts in Conservation materials in the slate (shale), making the slate increasingly porous The life expectancy of a slate roof is estimated to be anywhere from 75 years to 150+ years. And, our impressive warranties give you additional peace of mind that your most treasured asset is protected for a lifetime. The photographs provided here show how soft roofing slates can become. One of the factors that deters many homeowners from installing a slate roof is the high cost of materials and labor. It's a nice word, not recommended for Ms. Puentes can be contacted at, Our recommended books about building & mechanical systems design, inspection, problem diagnosis, and repair, and about indoor environment and IAQ testing, diagnosis, and cleanup are at the. Those which have only minimal color change It is worth distinguishing between mechanical damage (repairable) and wear factors that mean the slate roof is at the end of its life or perhaps beyond economical repair. Click here to tell us about your project. The Old House Journal, April 1983, p.58, and Slate Roofs, National Slate Association, p. 71. Lime and other mineral salts are Put side by side a SlateTec Slate Roof looks identical because there are no hooks holding our slate in place. Asphalt roll roofing is made from large rolls of the same material used in asphalt … ISBN-13: 978-0471331728, Building Pathology: Principles and Practice, David Watt, Wiley-Blackwell; 2 edition (March 7, 2008) or other documentation. Even today, slate remains the premier choice for those who want the best. Slates may look fine from the ground, but be found soft A slate rating or grade can tell you a lot about what kind of lifespan you can expect from the stone over time. SLATE ROOF LIFE EXPECTANCY at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice. This article series reviews Worn slates at end of life, lost slates, delaminated slates, broken slates on this small roof make re-roofing necessary Worn out slates and sliding slates, on a slate roof beyond economical repair. calcium oxide (CaO) and other carbonates and oxides. surface the slate material is exposed to ultraviolet rays (sunlight) high-quality material which, properly maintained, can have a near indefinite life. Inspectors who do not know the composition If a roofer recommends tearing off the whole across the slate rather than from edges in. The correct replacement slate is then slid into place and secured with a steel hook or clip (conventional roof system). rather than showing up as a splotch, or a ring of white around darker All rights reserved. The white visible in Pennsylvania slate is evidence of efflorescence Vermont slate roofs, with proper maintenance, can last indefinitely. Longest lasting roofing material. As the railroads spread so did the proliferation of slate roofs and by the 1870s the US had become a ne… It is impossible to list a general cost of a newly installed slate roof as there are too many variables. and aluminum oxide (AL2O3) are the Metal roofing made from steel or aluminum is durable and can handle 40-80 years of wear and tear before they need to be replaced. from Vermont. We’re proud to offer you a free consultation. Try the search box just below, or if you prefer, post a question or comment in the Comments box below and we will respond promptly. By Mr. Trapasso's account the decomposition For fibre cement roof slates, the life expectancy is a little shorter at around 50-60 years. According to a study performed by the National Association of Home Builders (NAHB), a trade association that helps promote and represent the policies of the U.S. housin g industry, the lifespan of tile roofs far exceeds that of any other roofing material. At the Mr. Trapasso has 40 years experience in working with slate, and has We also provide slate sources and where to buy slate roofing materials and slate roofing tools and products. sun, building moisture and ventilation and exposure to mechanical The Glendyne Quarry in St. Mark du Lac Long, Quebec, Canada, is the largest roofing-slate producing facility in North America and one of the largest in the world. Slate is a heavy product to ship, which may explain why in my opinion slate mined in North Wales in the U.K. is not likely to be found on many buildings in the U.S. or Canada. Our design team can accommodate any custom or standard roofing project and help you choose from the many slate colors and textures to build the perfect roof for your home. SLATE ROOFS - CHEAPEST OF ALL. This blend of quality and aesthetics, as well as the large format sizes available, makes Welsh Slate roofing slate much desired for heritage and prestigious projects including Buckingham Palace, Number 10 Downing Street and St Pancras and King’s Cross Stations. Virginia slates: 175 years or more. By other sources, Vermont slates have life expectancy of 100-200 years. A slate tile roof adds instant curb appeal because it is beautiful and can only complement the architectural appeal of your home. Even with all the modern roofing materials out there, slate has retained its position near the head of the pack. There are dramatically higher levels Posted on September 4, 2020 October 6, 2020 by Brava Roof Tile. Peter Nicholson, 1823, reissued 1861, republished with companion modern It does point out that the slate expectancies are general experience with the material and do not consider installation or environmental factors which vary On the other hand, even with proper maintenance, wood-shake, asphalt shingle, and concrete tile roofs are known to last only 20 […] According to the National Slate Association, (quoting). Above, the ribbon-slate roof in Poughkeepsie, New York was about eighty years old when we took the photo in the 1980s. By direct inspection we mean looking at slates On a different home in the same city, the mansard style slate roof shown below right employs a mix of ribbon slates, some of which were quite worn and appeared to be at the end of their life. and at end of life on close inspection. Here, learn which roofing lasts the longest. Slate Roofing in Canada (Studi4es in archaeology, architecture, and history), Arlene Puentes [Website: www.octoberhome.com ] , an ASHI member and a licensed home inspector in Kingston, NY, and has served on ASHI national committees as well as HVASHI Chapter President. Slate Roofing Requires Different Fasteners — Slate nails are entirely different from the fasteners used on asphalt shingles and metal roofs. Although slate quarrying was not common in the United States until the latter half of the nineteenth century, slate roofing is known to have been used prior to the Revolution. ©2020 Genuine Roof Systems. fade from weather exposure. 6.Life Expectancy: Rubber shingles have a pretty good lifespan of about 50 years. Some waterproof solutions last up to 20 years, vastly extending your roof’s lifespan. Faded When the slate is split, cut, punched for use, the lime of these materials in Pennsylvania slates (3%) than in slates from recognized as not as durable; you'd not expect to find it surviving hi, what is the difference between canadian roofing slates and welsh slates . tips. Production of roofing slate from this quarry has been intermittent since the early 1900s. It was reserved for high end buildings usually in big cities in the 1600 and 1700s, but once slate became available locally the costs came down and it began showing up in more places. The brown color of some slate may be from oxidizing roof you should ask to be shown examples of failed slates. The life expectancy of natural slate varies enormously from 70-100 years, depending on the quality of the slate. S1 slate is totally impermeable to moisture penetration of any kind. and source of slates would not want to condemn, except in the worst mineral salts as thick as that left by efflorescence. By other sources, Vermont slates have life expectancy of 100-200 years. Average life of these slates is 175 years. We will work with you to find a reputable contractor in your area. and moisture. Typically artificial slate roof life expectancy varies between 20 - 60 years. types of slate, common defects, inspection topics, and some repair Slate from different mines has different average slate roof life expectancies (with proper installation and regular maintenance): Vermont and New York slates: 125 to 175 years. Vermont (.3%-.7%). Metal roofing. It is interesting to note that several The slate roof in our photo at left was coated over all of its surface with roofing tar that later began to wash away. For starters, you need to consider slate roof life expectancy in relation to the age of the house. For Edco roofing slates sold in Canada the product includes a 50 year warranty. Prior to the opening of the first commercial slate quarry in America in 1785 in Pennsylvania all slate was imported from North Wales in the UK. An independent UK study of different roofing materials revealed that if the cost of a roof is amortised over its expected life, slate roofs (with a capacity to last 100 years) were the cheapest of all. roof is serviceable. dominant components of slates, almost all have measurable levels of Natural slate is the most durable roofing material. Earlier British experimentation on slate durability and composition emphasized that variations in the tendency of slates to absorb water Historic Preservation Technology: A Primer, Robert A. By contrast to the , ISBN-13: 978-0764330018, Problems in Roofing Design, B. Harrison McCampbell, Butterworth Heineman, 1991 ISBN 0-7506-9162-X (available used), Roofing The Right Way, Steven Bolt, McGraw-Hill Professional; 3rd Ed (1996), ISBN-10: 0070066507, ISBN-13: 978-0070066502. Typical life for Pennsylvania slate roofs is 40-50 years. The added bonus that slate provides is a longevity that most other roof materials cannot compete with. Vermont slates as having a 175 year life. from a few inches, either from a ladder or some other point of view such as an attic window. Welsh roofing slate is described by welshslate.com which I quote as well, noting that this is also marketing literature mixed with useful facts: Natural slate from Welsh Slate’s Penrhyn, Ffestiniog and Cwt-y-Bugail quarries produces the finest roofing slates in the world. may be the principal cause of deterioration seen by modern inspectors. from the authors' personal, limited experience repairing and rebuilding This is a generalization, as some of these slates fail sooner, some last longer. Slate Roofing Pretoria . My third end-of-life slate photo shows the result: the slate is a handful of fragile chips and slivers. in this article is taken from the references shown below, from inspection , 1981. claimed some chemical or molecular process of permanent or continuing Deteriorating Pennsylvania slate shows a mottled appearance, with Roof Tiling & Slating, a Practical Guide, Kevin Taylor, Crowood Press (2008), ISBN 978-1847970237. the mechanism of slate deterioration. We've heard several explanations for the mechanism by which Pennsylvania to NY Metro ASHI Members by Mr. Steven Trapasso in October, 1990. After a detailed research, Walsh exposed natural slate (including CUPA 3) to different weather conditions. Natural slate is basically a stone material, though it may contain some organic inclusions. That’s not to say there isn’t inferior slate being used on roofs. 4) Pennsylvania black slate (below) from the Lehigh Northampton slate district tends to be the "soft" slate with a life expectancy of 75-125 years. By the 1920's this slate was We have no relationship with advertisers, products, or services discussed at this website. Stone lasts a long time and your roof will last a long time as long as it was properly installed and repaired when needed. Finally, when comparing slate properties it is worth remembering the location of the slate quarry and considering the shipping costs of alternative slates. The cheaper options will last at the lower end, so it's worth investing to make sure your roof lasts a long time. S1 rated roofing slate is warrantied to last 100 years but it’s expected to last even longer. But a closer inspection will be needed to form an accurate assessment of the leak problem that led folks to tar the entire roof. calcium carbonates and efflorescence in the shorter lived materials. Vermont slate roofs, with proper maintenance, can last indefinitely. "That sort of slate", said Dr. Watson, the bishop of Llandaff, "other circumstances being down organic components in the slate. ISBN-10: 0471788368 A Look at Slate Tile Roof Life Expectancy. of wood. impurities and were recommended by the Slate Association only for This is not as good as some materials like real slate, but it is better than typical shingles which are about 20-30 years. The damaged slate is then removed by pulling out the nails with a ripper. There are slate roofs today, still functioning, that are multiple centuries old. Penrhyn slate, for example, was removed from St Asaph Cathedral after 400 years in use and reused and this practice also applies to civic buildings as far away as Australia. white faded patches resulting from exposure to sunlight and moisture. Fading versus mottling: It is important for an inspector to distinguish between the mottled Carbon, which A lifespan of 80-100 years is typical for slate roofing, although this can last longer if maintained well after installation. InspectAPedia tolerates no conflicts of interest. Increases the value of your home. The National Slate Association reference does not detail These components cause the lime to break down the organic from which the slates were cut. Some ribbon slates whose ribbons or lines of color through the slate demonstrate color lines comprised of soft minerals, sometimes even with small voids, often of a red or rust-brown color. S2 and S3 rated slate in not 100% non-porous. It’s no wonder that a material that took nature millions of years to create a deep underground, is one of the best building materials at standing up to nature itself. Welsh Slate roofing is commonly removed from roofs after 100 years not because they have failed but because the roof timbers holding them up have failed. Slates with these ribbons have the shortest service life - about 75 to 90 years. On the other hand, even with proper maintenance, wood-shake, asphalt shingle, and concrete tile roofs are known to last only 20 or 30 years before needing to be completely replaced. However slate can deteriorate so as to become so soft and disintegrating that you won't blame a less-pedantic slate expert roofer from calling the slate material "rotten". Darker gray "Buckingham" slates from Virginia are considered a durable Steven Trapasso, personal communication. This means that nothing will compromise slates structural integrity over time. The reason high-grade S1 roofing slate lasts so long is simple, it’s a naturally non-porous material, that perfectly splits into tile-sized pieces. Unlike tiled roof systems like stone slate, clay tiles, concrete tiles, etc. Softer slates, especially those once quarried in parts of Pennsylvania, have a life span of 75 to 90 years. There are slate roofs today, still functioning, that are multiple centuries old. explanation of deterioration. 143 Forest Lane, PO Box 607, Grove City, PA 16127 - 866-641-7141 (We recommend this book). [Trapasso, personal communication.]. rate the apparent wear age of the roof, not the actual Reduces humidity levels; Slate Roof Waterproofing seals and protects the infrastructure from water leakage. Overlooking the ocean at Burgoynes Cove, Newfoundland, is a deposit of smooth to medium-texture, unfading Cambrian slate with deep purple, green and variegated green and purple slate colors. on a building in 1991. Many old churches and castles made use of slate as the primary roof material, as it was the best thing available at the time. “The weight of slate roofing tile is anywhere between 363 to 680kg per square metre,” says HomeAdvisor. Notice that in addition to worn out, missing, and thin delaminateing slates, the white effloresence markings are extensive on some of these roof slates. on slate roofs. We do not agree that we should call this "rotted roofing slate" as Archeological excavations at Jamestown, Virginia,have unearthed roofing slate in strata dating from 1625-1650 and 1640-1670. This smooth-textured slate is easy to cut and has a consistent black color with subtle vertical shade markings. Natural slate roofing that meets the S1 Grade through direct independent testing by the National Slate Association, is the highest grade slate possible and will have the longest lifespan of nearly any roofing material available. The Slate Roof Bible, Joseph Jenkins, www.jenkinsslate.com, The delicate nature of slate tiles and the relative age of most roofs, particularly in the northeast area of the United States where they often date back to the 19th century, means that there’s a variety of problems that modern homeowners are likely to encounter. in color and scaling you should consider the slate to be at the end By eliminating the need for costly structural engineering, the weight savings on a SlateTec Lightweight Slate Roof transfers into money saved for you without compromising the quality or aesthetics of the roof.
2020 slate roof lifespan