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Skylights, saving you energy and money with a natural light...

Nearly everyone likes skylights. They let in light and warmth, provide a convenient place to hang indoor plants, and simply brighten up an entire room. Properly installed, roof skylights can add a touch of class to even a rather drab kitchen, bathroom or other room in your house. However, old and leaking, or incorrectly installed roof skylights are a never-ending nightmare that will have you swearing never to have another skylight in your house.

Skylights come in many shapes and sizes, and may be traditional glass or the lighter weight vinyl skylight with plastic glazing. They can be flat or domed, and you can combine multiple skylights for a lighting effect that will reduce your utility bill. Even if you have an attic, you can still have skylights in the form of tubular skylights, which use long metal tubes-also called “sun tunnels” to reflect the light down into your room.

When you purchase a skylight, it will usually come with everything needed to install it except the tools and the carpenter. The smaller skylights, especially the tubular skylights, look deceptively easy to install, but we do not recommend installing them yourself. You might pay a professional a few hundred dollars to do it right, but cutting a hole in your roof is not something for an amateur to do. If you accidentally cut in just slightly the wrong place, cut the hole the wrong size, seal the flashing incorrectly, or damage any of your roof tiles in the process, you will wish you had never thought about skylights. In addition, if a skylight leaks, you cannot only end up replacing your roof, but also the ceiling beneath it along with the insulation or anything else that the water was able to reach. Correctly installed, however, a skylight will be as stable and dependable as the rest of your roof, and you will enjoy the ambiance for many years.

The following tips will help you find the right skylight and the right contractor to put them in your home.

Consider the design and location of your home. If you are in a southern climate, you probably will not want skylights on the south side of the house unless you also install some sort of reflective blinds. Otherwise, you will have both light and heat, driving your air conditioning bill up during the summer. In colder climates with more moderate summers, the blinds are and option.

Ask the contractor for references. How many other skylights has he installed? Try to contact people who have used his services and look at their skylights. If you cannot arrange an opportunity to inspect installed skylights in other homes, at least get some reactions from other customers. Would they use that contractor again?

What warranty is offered? If there is any problem with the skylight once it has been installed, will the contractor return to fix it? For how long? What is the warranty on the skylight itself if it happens to be defective? (Although it can happen, a leaking skylight is seldom the result of defective material. Ninety percent of the time, a leaking skylight is the result of improper installation or of taking shortcuts in an attempt to save time and money.)

If you already have a skylight and just need to replace it-and there is no need to replace the roof itself-the task will be simpler and less expensive. If you are installing a new skylight, it will obviously cost more. However, save up the money and have it done correctly the first time. You will never regret erring on the side of caution.

By letting natural light stream in, skylights fill rooms with warmth and a feeling of spaciousness. By reducing the need for electric lighting and adding winter warmth, they help trim energy bills. Moreover, clear ones give you a window to the starry night sky.

A skylight is like a window in the roof, but its frame is designed and flashed to withstand the rigors of rainfall that a roof receives. As shown here, a skylight’s flashing works in concert with the roofing material to usher away rain and snow.

Newer skylights are virtually leak-free, thanks to rugged construction and easy-to-install, integral flashings. They are also equipped with channels that carry away condensation.

Though some frames are solid wood or aluminum, most new skylights are made of a combination of metal, vinyl and wood. The exterior frames tend to be aluminum cladding with a durable finish–the part you see inside is often made of solid wood, plywood or white vinyl.

Some skylights are glazed with acrylic or polycarbonate, others with glass. Plastic ones are lightweight, economical choices often put where a skylight could be easily broken. Because they are molded, they come only in standard sizes and shapes: flat rectangles, bubbles, domes, pyramids, ridge-shaped, dormer models, and so forth.

Many people prefer Glass because it does not scratch as readily as plastic does and because it is available in nearly limitless sizes and types. You can get single, double or triple glazing with energy-saving low-E glass or argon-gas-filled panes. For use where the sun may damage carpets and furniture with ultra-violet (UV) rays, you can get bronze-tinted or other UV-blocking glass.

Other options for eliminating or reducing the sun when it is not wanted include built-in blinds, horizontal curtains or shades and UV-blocking insect screens. Cross-section view of a glass skylight shows key parts and how the flashing provides continuous drainage down the roof. A skylight’s shaft governs how light is delivered to the room below. If all four sides are flared, light spreads over a wide area. A shaft with perpendicular sides focuses the light straight below. If the shaft is flared on only one or two sides, it sprays more light in the flared direction.

If you are interested in getting skylights in your home, the best place to look is on Repairfinders.com. On this site, many contractors in your area are willing to assist you with this. Remember not only does having a skylight help the environment, but it also save you money, gives you beautiful natural light, makes rooms look larger, and adds to the quality of your property.

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Do you know the difference between Cement and Concrete? Now...

Today is such a beautiful day! I have always found Thursdays to be a bit boring, but today is such a nice day. I figured that since I am in such a good mood, we could do something “educational”. Instead of giving you the inside scoop today, I am going to give you information. Doesn’t that sound fun? Well let us get to it. Be prepared to learn a lot, because I know you do not know much about cement.

Many people talk about cement when they mean concrete.

Cement is a fine-grained compound that turns into a solid when mixed with water. Cement is used to bind mixtures of materials into a composite solid.

Concrete is a mixture of cement, sand and gravel. That is, cement is the glue of concrete. Now that we have made that clear, let us talk about cement. Cement begins with lime.

Lime, the First Cement

Lime is a substance used since ancient times to make useful things like plaster and mortar. Lime is made by burning, or calcining, limestone-and that is how limestone gets its name. Chemically, lime is calcium oxide (CaO) and is made by roasting calcite (CaCO3) to drive off carbon dioxide (CO2). That CO2, a greenhouse gas, is produced in great quantities by the cement industry.

Lime is also called quicklime or calx (from Latin, where we also get the word calcium). In old murder mysteries, quicklime is sprinkled on victims to dissolve their bodies because it is very caustic.

Mixed with water, lime slowly turns into the mineral portlandite in the reaction CaO + H2O = Ca(OH)2. Lime is generally slaked, that is, mixed with an excess of water so it stays fluid. Slaked lime continues to harden over a period of weeks. Mixed with sand and other ingredients, slaked lime cement can be packed between stones or bricks in a wall (as mortar) or spread over the surface of a wall (as render or plaster). There, over the next several weeks or even years, it reacts with CO2 in the air to form calcite again-artificial limestone!

Concrete made with lime cement is known from archaeological sites in both the New and Old World, some more than 5000 years old. It works extremely well in dry conditions. It has two drawbacks: Lime cement takes a long time to cure, and while the ancient world had lots of time, today time is money.

Lime cement does not harden in water but stays soft, that is, it is not a hydraulic cement. So, there are many situations where it cannot be used.

Ancient Hydraulic Cement

The Pyramids of Egypt are said to contain a hydraulic cement based on dissolved silica. If that 4500-year-old formula can be confirmed and revived, it would be a great thing. However, today’s cement has a different pedigree that is still quite ancient.

Around 1000 BCE, the ancient Greeks were the first to have a lucky accident, mixing lime with fine volcanic ash. Ash can be thought of as naturally calcined rock, leaving silicon in a chemically active state like the calcium in calcined limestone. When this lime-ash mixture is slaked, a completely new substance is formed: calcium silicate hydrate or what cement chemists call C-S-H (approximately SiCa2O4 · xH2O).

C-S-H is still a mysterious substance today, but we know it is an amorphous gel without any set crystalline structure. It hardens fast, even in water. In addition, it is more durable than lime cement.

The ancient Greeks put this new cement to use in new and valuable ways, building concrete cisterns that survive to this day. But Roman engineers mastered the technology and constructed seaports, aqueducts and temples of concrete as well. Some of these structures are as good as ever today, two thousand years later. However, the formula for Roman cement was lost with the fall of the Roman Empire.

Modern Hydraulic Cement

While lime cement continued in use throughout the Dark and Middle Ages, true hydraulic cement was not rediscovered until the late 1700s. English and French experimenters learned that a calcined mixture of limestone and claystone could be made into hydraulic cement. One English version was dubbed “Portland cement” for its resemblance to the white limestone of the Isle of Portland, and the name soon extended to all cement made by this process.

Shortly thereafter, American makers found clay-bearing limestone’s that yielded excellent hydraulic cement with little or no processing. This cheap natural cement made up the bulk of American concrete for most of the 1800s, and most of it came from the town of Rosendale in southern New York.

Rosendale was practically a generic name for natural cement, although other manufacturers were in Pennsylvania, Indiana and Kentucky. Rosendale cement is in the Brooklyn Bridge, the U.S. Capitol building, most 19th-century military buildings, the base of the Statue of Liberty and many other places. With the rising need to maintain historic structures using historically appropriate materials, Rosendale natural cement is being revived.

True Portland cement slowly gained popularity in America as standards advanced and the pace of building quickened. Portland cement is more expensive, but it can be made anywhere the ingredients can be assembled instead of relying on a lucky rock formation. It also cures faster, an advantage when building skyscrapers a floor at a time. Today’s default cement is some version of Portland cement.

Modern Portland Cement

Today limestone and clay-containing rocks are sintered-roasted together at nearly melting temperature-at 1400° to 1500°C. The product is a lumpy mixture of stable compounds called clinker. Clinker contains iron (Fe) and aluminum (Al) as well as silicon and calcium, in four main compounds:

  • Alite (Ca3SiO5)
  • Belite (Ca2SiO4), known to geologists as larnite
  • Aluminate (Ca3Al2O6)
  • Ferrite (Ca2AlFeO5)

Clinker is ground to powder and mixed with a small amount of gypsum, which slows down the hardening process. And that is Portland cement.

 

 

Making Concrete

Cement is mixed with water, sand and gravel to make concrete. Pure cement is useless because it shrinks and cracks; it is also much more expensive than sand and gravel. As the mixture cures, four main substances are produced:

  • C-S-H
  • Portlandite
  • Ettringite (Ca6Al2(SO4)3(OH)12 26H2O; includes some Fe)
  • Monosulfate ([Ca2(Al,Fe)(OH)6] (SO4,OH,etc) xH2O)

The details of all this are an intricate specialty, making concrete as sophisticated a technology as anything in your computer. Yet basic concrete mix is practically stupid proof, simple enough for you and me to use. You see though we are smarter than that, we will not go around messing with cement and concrete mixes, because we know we should leave that to the professionals. So if you need a professional, check out repairfinders.com where they have only the best in the business, and you will never be let down. Jack is over and out.

 

 

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