Resetting the drums, if needed: If the drums were incorrectly set in their old positions, one must reset both drums in new positions on the shaft. This is complicated by the presence of old dimples in the torsion shaft from previous setting(s), which must be avoided lest they improperly influence the new setting of the drums. To begin this process of resetting the drums, the door must first be lowered and resting level on the floor, the spring(s) must be in the unwound condition with their set-screws loosened, and the lift cables wrapped around the drums. If for some reason the door does not rest level on the floor, such as the floor being uneven, then insert temporary shims between the door bottom and the floor to bring the door up to level. Loosen the set-screws on the drums, and turn the torsion shaft to avoid the old dimples from the set-screws in the old drum position. Tighten the set-screw on the left drum (that is, on your left as you face the door from in the garage), creating a new dimple, and apply tension to its cable with the locking-pliers technique, enough tension to keep the cable taut but not enough to start to move the door up. Attach and wind the cable on the opposite (right) drum by hand until the cable is similarly taut, and set the screw, remembering that tightening the screw will tend to add a bit of extra tension to the cable. Both drums should now be fixed on the torsion shaft, with the cables about equally taut (listen to the sound when you pluck them like a guitar string) and the door still level on the ground. Setting the left drum first, and the right drum second, will allow you to take up any slack in the cable introduced by the left drum rotating slightly with respect to the torsion shaft as you tighten the set screws. This alignment and balance of the cables, drums, and door is critical to smooth operation and proper closing. If you have a single-spring assembly, the distance along the torsion tube from the spring cone to one drum is longer than to the other drum, which allows a bit more twist to one side than the other, and you may have to compensate with the setting of the drums.

Garage Door Service Co


Great!  We specialize in all sorts of garage door repair work.  Working around the garage door can be fairly dangerous if you’re trying to repair this issue on your own.  Most garage door companies will quickly remind folks about this, and it’s true.  Their are some hazards to watch out for when working around these heavy and high tension doors.  We recommend you give an expert a call to address the issue in a safe and timely manner for you.

We take the garage door installation process very seriously. The way a garage door is installed will impact every aspect of it for years to come. The noise level, ease of use, wear on other parts, appearance, and even out of pocket repair costs over the life of the garage door are all a direct result of how well the installation was performed. Call us today and you will see firsthand the A1 difference. Years from now you will be happy you chose A1!
Align the upper roller tracks by carefully lifting the door halfway. Lock it in place with two locking pliers, and install the supporting brackets on the back of the rails using 1-1/4 in. perforated angle iron (available at home centers and hardware stores). Install 1-1/2 x 1/4 in. stop bolts, with the threads to the inside of the track, at the end of each upper track.
Garage doors cause injury and property damage (including expensive damage to the door itself) in several different ways. The most common causes of injury from garage door systems include falling doors, pinch points, improperly adjusted opener force settings and safety eyes, attempts at do-it-yourself repair without the proper knowledge or tools, and uncontrolled release of spring tension (on extension spring systems).
The not-so-competitive advertising trick: How about this racket: We have all heard how you should get at least three bids for any home improvement jobs, right? In some areas the largest ads in the yellow pages are from a single business using various names and phone numbers, masquerading as independent competitors. When you call asking for prices, "they" all quote you very high numbers. You are tricked into thinking you have shopped around for the prevailing price. (The more modern version of this is multiple Web sites that all direct you to call the same person.) If you've ever had to call a plumber you may have unknowingly been a victim of a similar trick.

Garage doors can cost $200 for a single door and up to $4,000 for two doors or more. Keep in mind that better materials will cost more. This price also includes purchase of new tracks, adhesives, connectors and fasteners. You could install the door yourself but the weight of some garage doors are extremely heavy, so make sure you have help if you are trying DIY garage door replacement. Contact a professional or do research online to find out the average weight of different types of garage doors. 

The Heavy Duty Chain Extension Kit for 8 The Heavy Duty Chain Extension Kit for 8 ft. High Garage Doors is required for reliable everyday operation of Chamberlain heavy duty chain drive models in 8 ft. garage door applications. Featuring a quick-install extension rail and replacement chain the kit includes everything needed for quick and easy installation. Includes ...  More + Product Details Close
Garage doors cause injury and property damage (including expensive damage to the door itself) in several different ways. The most common causes of injury from garage door systems include falling doors, pinch points, improperly adjusted opener force settings and safety eyes, attempts at do-it-yourself repair without the proper knowledge or tools, and uncontrolled release of spring tension (on extension spring systems).
Finally, we also carry any and every residential garage door product that you need to have a state-of-the-art, secure and safe garage door. We are proud certified dealers of Clopay doors, the most durable and versatile doors on the market. With over fifty years of garage door manufacturing experience, you can trust Clopay quality, just as you can trust our team to install these highest-quality doors.
Welcome to Jarusewski’s Overhead Door Service Inc. We are a locally owned company that has been providing the Carlisle, PA area with garage door sales and service since 1988. We specialize in installation, repair and maintenance of residential and commercial garage doors. Our garage doors are reliable, affordable and most importantly safe.We know a great garage door installation is nothing unless you have a great garage door to install. That’s why we feature the best brands when it comes to garage doors and garage door openers. We feature doors by Clopay, as well as, door openers by Chamberlain and LiftMaster Professional.
The disaster-is-nigh technique: As he inspects your door, the serviceman grimly calls your attention to "cracks" in your garage door. These appear very faintly in the middle of the door where the panels bow under their own weight when the door is up. This is normal, but the type of thing you wouldn't casually observe yourself. This surprising revelation disarms you, and you may find yourself strangely susceptible to the pitch for an entire new door.
One way to determine if you need a new garage door is to check the seal at the bottom of your door. If you see a gap, then perhaps you need to think about replacing your door. Or perhaps not. The seal, often called a rubber bottom, can be replaced. If the lower section is showing rot, then it may be possible to replace just that section. To find out if your garage door needs to be replaced or just needs a little TLC, call us. We'll help you explore the alternatives that are best for you.
A knowledgeable installer with good inventory can offer you upgraded spring lifetimes by using longer, heavier springs than were originally installed. For example, you may be offered more expensive springs with expected lifetimes of 15, 25, or even 100 thousand cycles, instead of the standard 10 thousand. The difference in labor to substitute this upgrade is nil. Since the dealer's cost of springs is proportional to weight, and typically a small part of the job price anyway, the dealer's cost for this upgrade is slight. This would seem to be a excellent option to offer every customer, and if correctly calculated and reasonably priced, one that you should take as cost-effective. Yet you may not be offered such an upgrade, if the installer is not adept at making the rather simple calculations, or if the optional springs are not on his truck, or if you're not around to be asked, or if the installer just doesn't like selling or taking time to discuss such details.

To estimate the maximum physical force required to wind these springs, consider that they are balancing the weight of the door with a torque applied to a lift drum on each end of the torsion shaft. The lift drums have a 2-inch radius, which is the standard residential size, and corresponds conveniently to about a 1-foot circumference. If we pessimistically assume the 10-by-7-foot door has a weight of 350 pounds, this implies a torque of 350 pounds on a 2-inch radius, that is, 700 inch-pounds, or 58 foot-pounds. Each of the two springs should be exerting slightly less than half of the balancing torque, or 29 foot-pounds. Compare this to, say, the bolts in an automobile, which are typically torqued to values of about 50 foot-pounds, or tire lug nuts, which may be torqued to well over 100 foot-pounds.

Once the shaft, springs, and center bearing plate come down and lay on the floor, the old springs should be easy to get off and new ones slid on and assembled. Two bolts hold the center cones to the center bearing plate. The bearing on the center plate can be oiled while it is exposed from having the springs off. At this point it is a relief to be working with inert parts while standing on the floor rather than energized parts while up on the ladder. You might think it would save a little time to replace the spring with the shaft left up on the wall, but I found it was easier and safer to lower the works down to the garage floor first.

If you wish to utilize our techs that are well-vast with working on different brand or style of entryway call us or sent us an email we shall respond immediately. We shall unquestionably take care of your business appropriately the first run. Before working with us, see to it that you know which neighborhood business practice what we do and what precisely are their qualities.


In 1992 the United States Consumer Product Safety Commission released new rules for automatic garage door openers. Anything manufactured after 1993 was required to include either an electric eye (a pair of sensors that detect an object obstructing the doorway) or a wall-mounted control button that users hold down in order to close the door entirely. Most manufacturers opted for the electric eye method, sometimes referred to as safety sensors.
Another moment of truth arrives as the winding-up of the springs begins. (I am just posing here with the camera held out in my left hand. Except for lifting the door onto the scale, this was a one-man job, including the photography.) The position of the bars in this photo was necessary to take the photo, and does not show a correct winding technique, You should not have to swing the bar up as high over the top as shown. The lower bar during winding should swing from pointing down to pointing a little past horizontal. Then you hold that bar horizontal while socketing the other bar pointing down, apply force to that (now) lower bar, then remove the (now) upper bar, wind one-quarter turn, and repeat.
Winding "up" starts out easy. It finishes at the proper number of turns, by which time you are pushing against the maximum torque. Count the turns of spring winding from when the springs are slack. To be sure you're winding the right direction, all you have to remember is that proper winding makes the spring smaller in diameter and longer in length as it twists "in". On the standard door (most common), this means you push the winding bars up to wind up the spring, which is an easily remembered rule. This is very apparent and should be verified during the first few easy turns. You can also think about the correct winding direction in mechanical terms, namely which way the reaction of the spring will torque the shaft and drums, which in turn will lift the cable. This should all make perfect sense before you attempt the manipulations.
While there might not be a huge price range when it comes to garage door openers—they are all quite an investment—there a few less expensive options to consider. Here’s a great budget option from Chamberlain. It has a motor that’s equivalent to ½ horsepower and chain drive system that is quick and easy to install. You can also connect it to the MQ technology (gateway sold separately) to use with your smartphone. The product comes with two three-button visor remote controls, a multi-function wall control, as well as a wireless keyless entry system. It comes with a 10-year motor, two-year parts, and one-year accessories warranty.

The low rating on the CS is due to the fact that inwas out of town and my wife called because the garage door wouldn't open. We had repairs to the only other exit, and the CS said because it could be opened manually, it was no emergency. She was stuck in the house for over Sixteen hours. No emergency crew came out. Steve, a tech who came out the first time, fixed the door. It is not his fault CS took their sweet time to help a 45 year customer. I commend Steve. I do NOT have anything good to say about CS.

Most styles, whether traditional or contemporary, feature panels, trim, and other detailing. Doors with true frame-and-panel construction tend to be sturdier than those with decorative detail that is merely glued or nailed on. Many styles have glass panels on the top row, which looks inviting from the street and brings daylight inside. You can also find roll-up doors with shatterproof glass or frosted plastic in all the panels, for a more modern look.


Thus it is humanly impossible to dodge a falling door. If the spring happens to break when the door is moving up or down somewhere in the middle of travel, as is more likely, then you'll have even less time. Hence it is not prudent to stand or walk beneath a moving garage door. Of course people often do, and the only reason this does not frequently kill people is that springs typically break at the bottom of travel, where they are stressed the most.
Hello Scott and thank you for the very nice 5 star review. John, our Tech, will be very happy too. I will review our on-phone quoting system after listening to your call and see if we can get better at more accurate pricing. It is just so tough to know exactly what is going on at the site and the extent of the repair until we set eyes on it. We will try to get better at it...I promise. Thanks again.

These are just my observations as a consumer; I am not on a crusade to change the garage door industry. But I will observe that the Web is the innovation that can finally give intelligent consumers the advantage in these commercial games. Trade restraints work only when all sellers in the market collude in and agree to the scheme. If anyone, anywhere is selling freely, then the Web can help you find them. In the years since I have first published this information, a number of reputable Web-based merchants have appeared to supply the parts you need to repair your garage door as a do-it-yourselfer (and I have linked many of them below).
Every thing the tech demostrated was helpful, he knew how to do his job even if his eyes were shut. Very knowledgeable, took time out to explain every detail about the install process. Very highly satisfied. A d would love to have him for future additional repairs. Would definitely recommend sears and would use you guys again thanks mr.technician for a job well done.
Our expert technicians arrive equipped with fully stocked trucks, ready to repair or replace any garage door and opener system including Liftmaster, Chamberlin, Sears, Craftsman, Genie, Clopay, Wayne Dalton, Amarr, Reliabilt, Raynor,C.H.I, and more. If the door system is unable to be repaired including Wayne Dalton torqmaster setups and needs to be replaced, our technicians are able to upgrade the garage door system with extension or torsion setups on the spot.
At this point I weighed the unlifted door to confirm and fine-tune my calculations. This is not strictly necessary, but it makes the adjustments easier to perform, if you happen to have a scale with the requisite capacity. With some helpers, we first lifted the door a few inches and rested it on blocks of wood to provide clearance underneath. Then I slid a 400-pound-capacity freight scale under the center of the door, we lifted again to remove the blocks, and lowered the door gently onto the scale. This door weighed in at 238 pounds, which is very heavy for a single-car door. Since the outside of the door carries the 3/4-inch plywood paneling to match the house, and that plywood weighs about 2 lbs/sq-ft, I estimate the door weight to be about 7 x 10 x 2 = 140 lbs of paneling with the rest 238 - 140 = 98 lbs the interior panels, hardware, and cobwebs. Knowing this total weight will help later in adjusting the torsion on the springs. After weighing, we removed the scale and blocks, leaving the door fully lowered again. Had I not had a high-capacity freight scale, I might have improvised a crude weighing device from levers and smaller weights of known mass, or a lever arm pressing a reduced proportion of the full weight onto a lower-capacity scale. Another factor to remember is that The weight of a wood door can vary with humidity.

If you are replacing an old garage door, the first step is to measure your garage opening to ensure you are choosing a door with the correct dimensions. Even if you feel confident that your door is a standard size, measuring first can help ensure that buying your door is an enjoyable and smooth process. View our installation guide to get the needed measurements for your door. If you find that you have an odd-sized garage door, use our QuickDraw tool to see how a specific model will look in your desired size. If you have a unique vision for your home's curb appeal, Clopay can also design custom garage doors to meet your specifications.
Replacing or repairing garage door panels help the garage door operate properly. This means less headaches just trying to get through the day. In addition to ease of getting in and out of your home replacing or reparing garage door panels help preserve the value of the home. Curb appeal matters, especially if the home is going to end up on the market for sale. Any exterior improvement you do to the front of your home pays dividends in your curb appeal. That being said, garage door panel repair is one of the highest dollar fixes you can do for your garage door. The cost to repair the panel is directly associated to the repairman's hourly rate. Installation of new panels start at $240 for a 9' panel and $690 or more for a 16' panel. If you are thinking about replacing your panels, think twice, you might be able to get a brand new garage door for about the same price. Check your options with your professional before replacing your panels.
No matter what time or day of the week you require our services, we are always here to help. There are no additional fees to have us come by during the evening or weekend, so we’ll be able to offer you our premium service on a schedule that meets your needs. Contact Precision Garage Door Service of Lincoln today to book a free estimate and experience the high quality service that we have been providing to residents of Lincoln for many years.
Door repair business advice (warning to consumers, you are not allowed to know this): Thinner wire is excellent for shortening spring lifetimes, lightening your inventory on a service truck, and getting paid for frequent service calls. This is why your industry chooses to set "standard" springs to have thin wire and despicably short lifetimes. If you want to maximize profits and fleece your customers, install springs that predictably break in about 7 years on a door that should last decades, even though it is just as easy for you to install slightly more expensive springs that should last the life of the door. Remember that the customer wanted the cheapest price, so you need not feel any guilt about this low-balling.
One might stack lumber or arrange some other low platform for a steady footing, instead of the ladder. The aluminum ladder shown here is the splendid 16-foot Krause Multimatic, which carries a Type 1A Industrial rating (300 pound working load); I highly recommend it. However, product liability apparently forced this company into bankruptcy in September 2000 and the company ceased operations in June 2001; see http://www.krauseladders.com (this Web site went dead sometime in mid-2002). The world is a dangerous place.
Measurements: With the door in the down position, I measure a wire size of 0.273 inches, outside diameter of 2.0 inches, and overall length of 41.5 inches. Relaxing the spring shortens the length by about 7.5 coils of wire, so to estimate the relaxed length, we deduct the wire diamter of 0.273 inches times 7.5 from the 41.5 inch wound length, yielding an estimated relaxed length of 39.5 inches. The mean coil diameter is 2.0 - 0.273, or 1.73 inches. Perhaps this was actually a 40-inch-long spring with a 1.5 ID, 1.75 mean diameter, and 2.0 OD, but let's continue on calculating with the actually observed sizes. The number of coils in the relaxed spring is the relaxed length of 39.5 inches divided by the wire size of 0.273 inches, or about 145 coils. Deducting about 5 dead coils at the ends yields 140 active coils.
Absolute Overhead Door recently launched a blog that can be found here so that readers would be able to see the benefits of a garage and what they should do in the event their newly driving teenage drove into the garage door. The blog offers many tips for “fix at home” solutions as well as giving examples of situations when calling us for a service call is the best decision. In our blog, we give professional and honest recommendations for the most reader and budget friendly options for families looking for advice that doesnt cost a fortune and an obligation to purchase a new garage door from a salesman afterwards! Check it out! We hope you enjoy it.
Screw - Screw-driven lift systems attach a long screw to the motor to move the garage door. These systems are powerful, fast, relatively quiet and require less maintenance than typical chain- or belt-driven systems. Genie and Overhead Door are two popular brands that make screw-driven systems. Based on our research of Genie’s line, you can expect to pay $244 on average for a screw-driven garage door opener.
With garage door installation costs, these numbers also include the actual purchase of the new door and other hardware, including the tracks, adhesives, connectors and fasteners. Keep in mind that if these numbers seem extreme, garage door replacement and upgrades can yield, on average, one of the highest returns on investments for homeowners — with an expected 85 percent.
These are just my observations as a consumer; I am not on a crusade to change the garage door industry. But I will observe that the Web is the innovation that can finally give intelligent consumers the advantage in these commercial games. Trade restraints work only when all sellers in the market collude in and agree to the scheme. If anyone, anywhere is selling freely, then the Web can help you find them. In the years since I have first published this information, a number of reputable Web-based merchants have appeared to supply the parts you need to repair your garage door as a do-it-yourselfer (and I have linked many of them below).

Removing winding cones from an old broken spring for reuse in a new spring: Springs without the winding cones installed are a little cheaper than with the cones. Twisting the old cones into a new spring is easy with a vise and pipe wrench, but it can be tricky removing old cones from a broken spring for reuse. To remove old cones, mount the cone in a vise such that the spring portion is free. Grab the last few turns of the spring in a pipe wrench, engaging the teeth of the wrench into the end of the spring wire. Turn the wrench against the end of the spring wire, releasing the end of the spring from its clamping onto the cone, as you twist the loosened spring off the cone. Another more certain if not brutal method is to use an angle grinder with a thin metal-cutting disk to cut through the loops of spring wire where the loops wrap around the cones, being careful not to nick the cone itself too much. You could also cut into the old spring loops with a just hacksaw and break off the loops with hand tools, but this will require a lot of effort.
As you go through the designer and create the style of door you like best, the options you selected are saved automatically, so that you can easily submit it to us for a free price quote. Submitting this form does not obligate you in any way and your email address and personal information are kept in the strictest confidence. See our privacy policy to learn more. The price quote you receive is an estimate and is NOT A GUARANTEED PRICE. Precision will, at no additional charge come to your home and provide you with a firm price. We just need to do some measurements before we can guarantee a price. Get started now by choosing a collection above!
Together with our alliances, we proudly serve all of Australia, including Adelaide, Brisbane, Gold Coast, Melbourne, Perth and Sydney, with top quality sectional garage doors, roller doors, steel garage doors, remote garage doors, tilt garage doors, timber garage doors as well as commercial garage doors, commercial shutters and industrial shutters. If you need custom garage doors, we’re the ones you need to call.  Our manufacturers have been selected for their capacity to meet and exceed our requirements for superior craftsmanship, reliability and a single-minded focus on excellence in customer service.
Note the left winding cone with red spray paint. This shpritz of paint is applied to create fear and doubt in the mind of the do-it-yourselfer. Sometimes it is a color code for the wire size (using a DASMA standard, red indicating 0.2253 inch diameter wire). Sometimes it indicates the winding direction: red may indicate right-hand winding, but don't rely on that; do you own independent analysis. Sometimes it is a manufacturer's private code for another dimension than wire size. This color code is for the installer's information when the spring is new; I would not depend on interpreting the color code properly on an old spring, since one can't be certain of a correct interpretation without documentation from the original supplier.
This opener is easy to install for most DIYers and comes with two remotes and a wireless keypad so you can open the door with a pin. If you are interested in having this smart-enabled you can purchase a separate kit to do so. The Safe-T Beam helps prevent accidents using a infrared beam that will open or close the door if a car is getting to close. 

In the photo, you can see an extra lag screw on the bottom of the plate, reinforcing weak anchoring from the original two screws (hidden behind the springs). This extra screw was applied by a professional garage door technician on a previous repair visit. I have since replaced the backing with a sound plywood panel anchored into the concrete door header. Since these bolts clamp all the opposing torsion to the wall, the attachment must be sturdy.


If the spring is broken near a winding cone, you might think you can remove and discard the short broken piece of spring from the cone, clean up the end of the long remaining spring, and insert that end into the cone. This is another extrememly risky improvisation. The shortened spring is not going to have the correct weight-bearing characteristics for the door, so you will not be able to balance the door properly. The shortened spring will be proportionately overwound, resulting in extra stress that will increase the expectation of another fracture. And the aging and history of the original spring being broken greatly increases the likelihood of another fracture at other locations.

The deluxe-model upsell trick: Don't you want the best? Don't you want to protect your family? Galvanized springs may be offered to you at extra expense as "longer lasting". Although bare springs (also called "oil tempered") can develop a light film of rust, the eventual failure is due to fatigue and not corrosion. The use of coated springs (whether galvanized, painted, powder-coated, or surface-converted) is mostly about appearance: the customer likes his new door to look shiny, and the customer doesn't like repair parts that show superficial rust from storage.


At this point I weighed the unlifted door to confirm and fine-tune my calculations. This is not strictly necessary, but it makes the adjustments easier to perform, if you happen to have a scale with the requisite capacity. With some helpers, we first lifted the door a few inches and rested it on blocks of wood to provide clearance underneath. Then I slid a 400-pound-capacity freight scale under the center of the door, we lifted again to remove the blocks, and lowered the door gently onto the scale. This door weighed in at 238 pounds, which is very heavy for a single-car door. Since the outside of the door carries the 3/4-inch plywood paneling to match the house, and that plywood weighs about 2 lbs/sq-ft, I estimate the door weight to be about 7 x 10 x 2 = 140 lbs of paneling with the rest 238 - 140 = 98 lbs the interior panels, hardware, and cobwebs. Knowing this total weight will help later in adjusting the torsion on the springs. After weighing, we removed the scale and blocks, leaving the door fully lowered again. Had I not had a high-capacity freight scale, I might have improvised a crude weighing device from levers and smaller weights of known mass, or a lever arm pressing a reduced proportion of the full weight onto a lower-capacity scale. Another factor to remember is that The weight of a wood door can vary with humidity.
Our business believes in high quality, expedient service. We don’t want to keep you waiting for parts, so that’s why we have a huge inventory of springs, weather stripping, remotes, keypads, screens, and windows in stock for most units. No matter what part of your unit needs service, we’re sure to have a part that will fit. Our inventory doesn’t cover only a large variety of manufacturers, but is composed of only the highest quality components. By choosing the best, we’re able to offer a warranty on all of our repairs.
When you're done watching this video you'll know how to determine whether the company you hired to replace your garage door spring installed the right size spring on your door. You'll also learn the consequences to your garage door opener if the wrong size spring is used. If you are having a problem with your garage door spring, the 2:30 minutes you spend watching this video is time will spent.
A knowledgeable installer with good inventory can offer you upgraded spring lifetimes by using longer, heavier springs than were originally installed. For example, you may be offered more expensive springs with expected lifetimes of 15, 25, or even 100 thousand cycles, instead of the standard 10 thousand. The difference in labor to substitute this upgrade is nil. Since the dealer's cost of springs is proportional to weight, and typically a small part of the job price anyway, the dealer's cost for this upgrade is slight. This would seem to be a excellent option to offer every customer, and if correctly calculated and reasonably priced, one that you should take as cost-effective. Yet you may not be offered such an upgrade, if the installer is not adept at making the rather simple calculations, or if the optional springs are not on his truck, or if you're not around to be asked, or if the installer just doesn't like selling or taking time to discuss such details.
It’s important to pick a door that suits the style of your house. If you live in a Craftsman bungalow, for example, you might want something that looks like the swing-out doors found on garages behind early Craftsman houses. Manufacturers of modern roll-up doors make them in styles that mimic the old swing doors, complete with faux strap hinges on the sides and a pair of handles flanking a deep groove in the center. 
Roller doors ("Sheet Doors"-USA) are usually constructed of corrugated steel. They evolved from cover window and door coverings.[4] Other materials can be used (e.g.; transparent corrugated fibreglass) where strong impact resistance is not required. Corrugations give the door strength against impacts. A typical single car garage roller door has a preloaded spring inside the rolling mechanism. The spring reduces the effort required to open the door. Larger roller doors in commercial premises are not sprung (except USA) and use a manual pulley and chain system or a geared motor to raise and lower (roll up and roll down) the door. Roller doors cannot be effectively insulated.
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