GARAGE DOORS - Leading Construction and Building Group

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The decision to be made when purchasing or replacing a garage door can be influenced by many factors. The correct decision as to which type of door and from which materials it is manufactured may be influenced by lifestyle and design criteria. A garage door is often the largest moving item in a home. Safety and convenience when moving this large item is paramount. Purchasers must ensure that the design of the door meets and complies with performance and design criteria that are internationally accepted. A manufacturers warranty should be obtained for both the garage door and if fitted the automation device.

A wide range of doors are available to the architect, designer and homeowner. The following will help you decide which door suits your lifestyle and compliments your home.

Materials used to manufacture garage doors

Garage doors have traditionally been manufactured from a variety hardwood timbers. The hinged garage door was manufactured with hardwood frames and slates. The hardwood frame was later substituted for a steel frame with hardwood slates. Today the finest timber garage doors are manufactured from meranti, cedar or other similar hardwoods. The cost and scarcity of hardwoods has forced the market to utilise saligna as a substitute for meranti. In order to be cost effective wooden doors may contain hardboard wood panels. The high maintenance factor and environmental impact on the ecology of the use of hardwoods has diminished the popularity of wooden doors.

By far the greatest numbers of garage doors are manufactured from steel. The maintenance free pre-painted steel doors provide the busy homeowner with an elegant modern solution to garage doors. They are available with various patterns pressed into the steel door panel. Complex raised panels to ribbed panels are available. In addition the steel used in the door panel may itself be embossed with wood graining for a natural look.

The minimum standard for a steel garage doors is one using galvanised steel. Galvanised steel is manufactured from a cold rolled base and has zinc applied to it by means of a continuous immersion in a zinc bath. The amount of zinc on the steel is what determines the corrosion resistance of the steel. This can be measured by means of thickness or by means of the total weight of zinc per square meter present on the cold rolled sheet. Certain steel manufacturers not only coat the steel with zinc, but with a combination of zinc and aluminium this steel is referred to as Zincalume or Aluzinc. Zincalume’s corrosive prevention properties are far greater than that of standard galvanised material.

The most commonly used steel for garage doors is pre-painted, where the galvanised or zincalume has been pre-painted by the steel manufacturer. These steels are referred to as Colourcoat, Cromadek, Colorbond and various other proprietary references to imply that the steel has been pre-painted. The most common paint used is a polyester paint. A base or undercoat is applied to the steel this primer is to ensure that the finishing coat bonds to the steel. A final or finishing coat is applied onto the undercoat. The paint thickness is normally between 20 and 25microns. Once the paint has been applied to the steel it is baked on the steel by means of a heat process.

Certain steel manufacturers have perfected methods of applying up to 200 microns of paint per finishing coat.

The thickness or gauge of steel used on garage doors varies according to the type of steel door used. Where the steel has to roll up thinner gauges are preferable. Where the doors tilt or, open in sections, thicker gauges are better suited.

Fibreglass has recently become a substitute product for teel garage doors. Fibreglass has no structural strength and is reliant on a frame to hold the door rigid. No standards exist for fibreglass doors and the corrosive resistance of the product can easily be offset by the lack of structural strength and unknown lifespan. These doors are often thin enough to allow light to be reflected through them.

Why different designs of Garage Doors?
The simplest of all garage doors are those that have the opening divided in two with a side hinged panel opening and closing each side similar to a gate. This door lost their popularity owing to the fact that almost 1300mm of driveway space was needed to open these doors. Heavy side hung garage doors tended to sag on the hinges, and light winds where sufficient to cause these door panels to slam either open or shut.

Tip up or tilt doors where identified as the solution to the hinged door’s problems. Tip up doors are have a one-piece panel for the entire garage door opening. They operate on one or another mechanism that reduces the required starting force of lifting the door. The operating mechanism could utilise weights or springs to counterbalance the weight of the door. The tilt or tip up door like the hingedgarage door takes up a considerable amount of driveway space and a car cannot park in front of the door whilst one is attempting to open the door. The tip up or tilt type door needs to open through he garage door opening requiring the opening and the door to be square and perfectly fitted. The door in the open position rests below the lintel of the garage thereby reducing the opening size of the garage by approximately 180mm. These doors swing out at the bottom then up and back. If one is opening one of these doors one needs to step backwards as the door opens. These doors can be automated. The movement of a 2100 mm high tilt door.

Roll up doors solve certain of the limitations of the tilt or tip up type garage door. The steel-rolling curtain (or door panel) opens behind the finished wall of the garage opening and does not swing into the driveway. The roll up door enables vehicles to park very close to the door without limiting the doors ability to open. The curtain open upwards in a track and the door rolls up above the garage opening allowing the full garage opening to be utilised for access. The opening of the garage may have be shaped, as the opening does not affect the operation of a door. These doors can be automated.

Sectional doors are those that open in sections, the door panel moves up vertically then normally horizontally at the top of the door. The panel of the door is constructed in a number of sections, each section is joined by means of hinges.

The side hinges hold wheels that run in a steel track The track runs vertically up the jamb of the door and then curves into the horizontal position. In order to reduce the effective weight of the door panel helical springs are used. These doors can be automated.

Sizes and Measuring Garage Doors
Most garages in South Africa are constructed to standard sizes. The standard height for a garage door opening is 2150mm measured from finished floor level to the underside of the lintel. The standard width of a single garage door is 2500mm and a double garage 4880mm measured from wall to wall. In order to save costs a smaller door has become common with a width for single doors of 2440mm.

The Width and Height of a garage door is not the only dimension that can influence which type of door will fit what also needs to be considered is the following:

The Head Room the size from the underside of the lintel to the ceiling or the roof trusses inside your garage.

The Nib size, the dimension from the end of the respective opening left and right to the outer wall of the garage, measured on the inside.

The Backroom, the space available from the lintel to the back of the garage without obstruction. (This is very important if a sectional or tilt door is to be fitted and automation is required)

How Doors Work

Doors That Tilt
Fold up or tilt doors operate on two basic mechanisms. The less popular weight system is a system in which a cable is attached to the pivot point of the door, this cable runs over a roller at the head of the door and is connected to a counterbalance weight. The weight moves up and down as the door opens and close to assist in the reduction of the weight of the door panel.

The more popular spring tip up mechanism is mounted at the jambs or sides of the door and a spring extends to assist in the reduction of the weight of the panel at the fulcrum point of the door. These mechanisms can normally spring a door up to 70 kg in weight for a single door and 140kg for a double door. The positioning of the power plate (the plate that holds the pivot point) is critical for proper operating of the door. The spring tip up mechanism is very popular on timber doors. The opening height of a tip up door is reduced by the thickness of the door plus the stopper that prevents the door touching the lintel (approximately 180mm). A 2100mm high door will move forward by 1200mm once the door panel is 1300mm from the ground. This loss of parking/driveway space can limit the number of cars that can be parked and effect land usage in complex and townhouse designs. Tip up doors are normally supplied with side barrel bolt type locks which accommodates padlocks. Headroom of 250mm above the lintel is normally required to automate a tip up door.

Continuous Curtain Doors
Continuous curtain doors are also commonly referred to as roll up doors these doors are the most popular steel doors sold in South Africa. They are manufactured from light gauge steel so as to allow a continuous curtain of steel to roll up at the head of the garage door. They are normally manufactured from galvanised, Cromadek or Colorbond material . These doors manufactured by various manufacturers in South Africa and differing levels of quality is what differentiates these manufacturers.

The engineering principals of roll up doors is to create a torque tube by means of a large wheel at the head of the door being covered by a sheet of light gauge steel to create a large diameter tube that is sprung by torsion springs to reduce the operating force of the door. This large diameter tube means that the tube at the head of the door does not have to revolve more than necessary to open the door. The wheels of a roll up door can be manufactured from plastic or steel. Steel wheels are preferable and are normally bushed to ensure that the bearing surface between the wheel and the axle is permanently lubricated. Wheels of superior roll up doors are not perfectly round but shaped to accommodate the curtain of the door in all positions. If the wheels of a roll up door are exposed in the closed position it means that the torque tube design of the door has been compromised and this will effect the life span if the door.

The curtain (or door panel) of the door has horizontal ribs impressed on it. The deeper the ribbing the stronger the oor. This curtain runs in a track, between the curtain and the track is a wool pile or nylofelt that creates a friction between the curtain and the track. The quality of the weave of the pile will to some extent determine the maintenance free lifespan of the door. The curtain is fitted with two guide blocks, normally incorporating a roller, attached at the bottom of the curtain to ensure that the curtain remains in the same position in the track and operates with a maximum ease.

The springs at the head of the door should be set up to ensure that the commencement operating force of the roll up door is no more that 15kg. Roll up doors normally have locks pre fitted by the manufacturer. There are a wide variety of locks that are fitted to these doors. The simplest lock is a lock cylinder with two locking arms.

The most complex and effective lock is a center lift lock with internal and external locking ability. Most doors are fitted with a bottom lift handle. A rubber weather seal is fitted to the bottom of the door to prevent moisture ingress and wind blown dirt. On higher quality doors this can be replaced without any specialised expertise.

Roll up doors can be automated by various means. The most effective and efficient means of automating a door is to connect an opener directly onto the wheel or drum of the door. Certain high quality doors have their wheels prepared to accept an opener. The opener is simply inserted over the axle of the door into the wheel.

This drives the door up or down utilising the full effect of the torque tube. Other methods of automating rollup doors such as lifting the doors from the bottom of the door tend to lift one side of the door at a time. This results in uneven wear of the weather stripping and an increase in the maintenance required on these doors. Certain operators lift the doors from the bottom using cables. These installations if carried out rofessionally are satisfactory, but are messy and unsightly. The lightweight curtain of these doors makes successful automation economical and cost effective.

Roll up doors can be manufactured in various sizes. Doors that are wider than 2500 and higher than 2700 should have purpose designed ribs to ensure that the strength of the door is maintained. Double door as well as doors up to 5000mm high by 5000mm wide can be manufactured. These high performance doors have custom designed wheels or drums with specialised tracks and component.

Slatted Doors
Slatted doors that roll up are manufactured from two basic materials steel and aluminium. The decision to use one or the other is driven by cost and location of the door. This drives the door up or down utilising the full effect of the torque tube. Other methods of automating rollup doors such as lifting the doors from the bottom of the door tend to lift one side of the door at a time. This results in uneven wear of the weather stripping and an increase in the maintenance required on these doors.

Certain operators lift the doors from the bottom using cables. These installations if carried out professionally are satisfactory, but are messy and unsightly. The lightweight curtain of these doors makes successful automation economical and cost effective.

Roll up doors can be manufactured in various sizes. Doors that are wider than 2500 and higher than 2700 should have purpose designed ribs to ensure that the strength of the door is maintained. Double door as well as doors up to 5000mm high by 5000mm wide can be manufactured. These high performance doors have custom designed wheels or drums with specialised tracks and component.

Steel Slatted Doors
These doors are commonly referred to as industrial doors. The doors are manufactured from a series of interlocking slats that form the curtain or panel of the door. These slats are roll formed from various gauges of steel. These slats are normally manufactured from galvanised steel that can then be painted once they have been roll formed. They are from 0.7mm to 1.2mm thick depending on the span or width of the door and the application of the door. Slatted doors unlike continuous curtain doors do not rely on a torque tube. The wheels on the slatted doors tend to be smaller than on roll up doors and the commencement roll requires less headroom. The slatted door however takes more space to roll up, as each slat needs to be accommodated. Slatted doors are manually operated on smaller doors, theses are referred to as push ups. The operating force required to commence operating one of these doors is great doors very often have an adjusted operating weight of 30kg or more. The curtain of these doors can be extremely heavy in which case a chain hoist with a gearbox is fitted to the door. This is often the only way to open and close an industrial door.

A bottom rail is fitted to the door which accommodates the lock. Waist high locks can also be fitted. These doors can also be fitted with automation devises. They tend to be more expensive than other automation owing to the weight of the curtain that is being lifted.

Access gates can be fitted to slatted doors as well as various other additional extras like crank handle opening and closing rather than chain operation. Slatted doors can be produced from perforated steel slates, which allow vision through the door but still provides maximum security.

Steel is also used to manufacture rolling grilles. Instead of a rolled slat as a curtain for the door a formed grill is utilities. Theses doors are popular to protect shop fronts or as secondary security measures in shopping malls. They may have straight link construction or have a patterned link construction. These grills provide maximum ventilation and visibility when shut.

Aluminum Slatted doors
Utilising the same operating mechanism as a steel roller door the aluminum version is used where a higher quality of finish is required or where corrosion of normal galvanised steel slates may present a threat to the life span of the door. The anodised or powder coated aluminum slates are extruded rather than rolled. Aluminum doors tend to be lighter than steel doors and easier to operate manually.

Sectional doors may be manufactured from timber, steel or fibreglass. The manner in which sectional doors are sprung in order to reduce operating weights is of prime importance. Two types of spring arrangements are commonly used. The safest of these methods is Torsion Springs. These are normally installed above the door at the head of the door on a steel axle. The oil tempered helically wound spring is contained by the axle, should the spring come loose of the plug windings on each side of the spring or come loose of the axle all that will happen is that the door will not open easily. Extension or tension springs are stretched in order to help lift the door. In the closed position the spring is in its fully stretched position. These springs are fitted above the rear horizontal’s of the track.

Should a safety cable not be fitted or fail to perform adequately, the spring either coming loose or breaking inside the garage can do significant damage to anything or anyone inside the garage.

The hinges of a sectional door are numbered according to which panel they are fitted onto. They maybe manufactured from galvanised steel or from composite plastics. The composite plastic hinge has the advantage of being quieter in use. The hinges perform two functions, they join the sections together and allow them to break when the door is used and the end hinges contain the wheels or rollers of the door. The wheels that get fitted to the track via the hinges are normally fitted with ball bearings for extended life These wheels have a galvanised shaft to prevent corrosion and polypropylene wheel surface to reduce the noise of the wheel in the track .

Various locking arrangements can be fitted onto sectional doors. Center locks, friction locks, slam locks can all be fitted to sectional doors. These are not required if the door is to be automated with an automatic opener. Double doors or doors that have been manufactured from thinner gauge steels may require stiffeners to be fitted at the time of installation.

Certain technologically advanced sectional doors may have a polypropylene curve fitted instead of a steel curve on the track. The curving of steel distorts the channel in the track reducing the size of the channel. This forces manufacturers to use smaller wheels than what the channel in the track is designed for. This results in rattling doors. Polypropylene curves reduce the wear on the wheel and allow the door to operate in a quieter manner.

Timber sectional doors are normally manufactured with 5 panels to a standard height door. Doors may be manufactured in slatted or raised and fielded designs. Each section is weatherproofed by means of a shiplap joint. manufactured from either meranti or saligna the door manufacturer selects timber of matching quality and grain to ensure that each sectional panel and each door matches. The manufacturer may stain or paint the timber with a colour impregnated weather resistant sealant to prevent moisture loss from the timber.

Steel sectional doors are manufactured from steel 0.4mm to 0.6 mm thick. The thickness of the steel determines the strength of the door. Most steel sectional doors are manufactured from pre-painted steels.

Automation of garage doors
Most garage doors can be automated making use of a 1/3rd horsepower motor being operated on 220volt power. Larger motors and 3-phase power are required on large heavy doors or where door are to handle a large volume of traffic.

Sectional and tilt doors utilise the same type of automation systems. These garage door openers are mounted at the top of the doors horizontal to the open position of the doors. These openers are either chain drive or screw drive. The advantages of chain drive are their cost and ability to be used on doors of various heights without having to custom manufacture an opening arm. Screw drive systems tend to be more expensive and their enclosed screw system is a smoother operating mechanisms.

The electronic systems linked to garage door oeners llow additional functions to be operated by their transmitters llowing garage door openers to be integrated nto the overall ecurity and automation in a modern household. It is best to fit automation to a garage door at the initial installation stage.

How much should garage doors Cost
The final price of a garage door depends on the choice of door type, the automation system that is added to it and who installs the door. Garage door prices do not vary dramatically on a regional basis.

The average cost of installing a door is between R200 for a roll up door to R 500 for a sectional or tip up door. The prices of slatted doors are not included as these are priced on enquiry.

The finest of these doors would use deep drawing quality steel that has been timber embossed. When complete no external fixings are visible on the doors. The bottom panel or section normally has a weather seal fitted. In quality doors this weather seal is fitted to an aluminium section and can be replaced by the homeowner. Each steel section is fitted with a number of steel styles. These styles perform two functions. They are there to provide a suitable base for the hinges to be fitted to them and they are fixed to the section of the door to provide strength. A quality door will have polyurethane bonding between the style and the panel of the door and the style will be affixed to the panel on two vertical faces. A standard door has four sections.

Certain steel sectional doors may be fitted with Top lights. These are available in a number of different patterns. The most popular is the image of a sunset. Other patterns include Colonial, Cathedral, Sunburst and various others. These Top lights apart from providing the door with an aesthetic appeal provide light into a garage when the door is closed.

Steel sectional doors are manufactured in various styles. A raised and fielded panel type door and a ribbed design type door. All sectional steel doors require less headroom than roll up type doors.

Steel sectional doors may also be used for industrial applications. Using a slightly heaver gauge steel these doors can be manufactured up to widths of 7000 mm and heights of 5000 mm.


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