Glass Guide

The following guide describes how to install and safely handle glass and windows.

Manual handling of glass

When having glass delivered with your items, our glass is supplied loose for you to fit on site and so if it is not handled or stored correctly, you risk breaking the glass, even if it is toughened. Please follow the below guidance:

  • Never put the glass directly onto a concrete floor! It will shatter! Always use timber laths on the floor and wall where it will be leaned against.
  • Wear protective gloves and never let the glass slide between your fingers as you will cut yourself.
  • Prior to delivery, ensure you have a clear area to put the glass, where it can be safely left until you need it.
  • Always stand the glass on edge, leant against a wall. Always protect the first piece that is leant against the wall, e.g., with vertical timber laths, or a sheet of ply. Never lay glass flat as there is a risk of it going into twist and shattering.
  • When leaning one glass piece onto the next, always make sure the pads stuck to the glass are between them. Never put glass directly to glass.
  • Avoid putting glass on the corner as this could break the unit, even if it is toughened. Always put the glass down squarely on the edge.
  • When moving the glass, please make sure that you are only picking up what you intend to. The glass can stick to the pads, or can be stuck through suction, e.g., you may only intend to pick up one pane, but the pane behind might be stuck to it. This will then drop when the glass loses its grip and could smash.

Most glass will be delivered loose. This means that it is easy to visually check off for damage. All glass is bubble wrapped. Please ensure that you unwrap these parcels while the courier is present, to make sure none of the glass is broken. The outer wrapping with be marked to show your postcode and be numbered as one of the items to your delivery. ALWAYS CHECK THE GLASS THOROUGHLY BEFORE SIGNING FOR THE DELIVERY. As with all items, unless you document any damage on the delivery note before signing, it cannot be replaced free of charge. Once signed for, the glass is your responsibility, so please follow this guidance.


The outer frame of a window is called the 'window frame' and the inner frames that fit within the 'window frame' is called a 'sash'. A casement is a type of sash that is hinged on one of it's edges. Glass can be installed into the sashes or directly into the window frame. When glass is installed directly into the window frame this is called 'direct glazed'. The word 'Profile' refers to the shape of the cross section of timber. A 'glazing rebate' is part of the profile of timber that receives the glass, packers, tape and beading.

The outer frame of a window is called the 'window frame' and the inner frames that fit within the 'window frame' is called a 'sash'. A casement is a type of sash that is hinged on one of it's edges. Glass can be intalled into the sashes or directly into the window frame. When glass is installed directly into the window frame this is called 'direct glazed'. The word 'Profile' refers to the shape of the cross section of timber. A 'glazing rebate' is part of the profile of timber that receives the glass, packers, tape and beading.

Glass Installation

Make sure the window is fully treated before glazing otherwise the glazing rebate will be impossible to treat. When having glass delivered with your items that have been manufactured by us, we supply glazing tapes as standard. We do not supply tape with our off the shelf products such as Jeld-Wen windows, unless the glazing tape is purchased separately. There are several different tapes each having their own purpose. The following is a guide on where these tapes are to be situated within the window and how to install them. Application of all tapes must be done at a temperature of 10 centigrade or above. If you are bringing the glass and window frame in from somewhere colder than the room you are glazing it is this will probably cause condensation to form on the glass which will be detrimental to the adhesion of the tape.

Foam Glazing Tape

Foam glazing tape is provided on a roll as in the photo below. The tape is sticky both sides. As it is unrolled one of the sticky sides is revealed. To reveal the other sticky side a yellow liner has to be peeled back but not until it is time to install the glass.

There are three sizes of foam glazing tape that we provide: 10mm by 2mm, 10mm by 1mm and 21mm by 1mm. The different sizes have different purposes as follows:

  1. The 21mm by 2mm imitation bar tape is used to stick the imitation stick on bars onto the glass inside and outside. The former step is only applicable if you are having imitation bars.
  2. The 10mm by 2mm tape is used to stick the beads to the glass.
  3. If there are no imitation bars then the 10mm by 2mm tape is also used to stick the glass directly to the glazing rebate in the frame or sash; see photo below.

Applying glazing foam tape to the glazing rebate.

Using the 10mm tape, slowly roll out the tape while sticking it to the glazing rebate keeping it flush with the top of the glazing rebate as in the first photo below. Apply the horizontal tape runs first and cut the verticals tightly in between as in the photo above and below. There must be no visible gaps between where the tapes meet as in the second photo below. If there are imitation glazing bars then you will now need to apply the 21x2mm imitation bar tape in the same way as you applied the glazing tape above.

Installing the glass into the frame

  1. 1) Make sure the glass and window is clean and dry. Clean your glass with methylated spirit before commencing any glazing work so it is free of grease and debris as this ensures the tapes adhere properly.
  2. 2) Place the window in a vertical position to glaze it.
  3. 3) Offer each piece of glass into situ without removing the lining on the glazing tape.
  4. 4) Inserting packers: In the case of glazing a sash, enter packers around the glass using the 'toeing and healing' method. It is essential that this is done correctly otherwise the casement could sag. You must make sure that packers are located according to how the opener is hung, e.g., side or top hung. See diagram below.
  5. Side hung casements: The diagram on the left illustrates how a glazing unit is to be packed within a casement that is hinged on one side using the 'toe and heal' method. The striped and dotted rectangles represent packers. The idea of the 'toe and heal' method is to use the glass as a brace to strengthen the casement using these packers. If this isn't done the weight of the glass could bear down on the casement and make it sag or even damage it. The bottom striped packers are inserted first which are always on the side that is hinged. These packers should be of a correct thickness as to level the edge spacer inside the glazing unit with the top of the glazing rebate. Levelling up the edge spacer with the glazing rebate isn't an exact science and it is mostly the case that the edge spacers are balanced up as best as possible all the way around the glazing unit. All packers should be about 50mm away from the corner they are next to. Next insert the two top striped packers so they are firmly wedged in without distorting the casement. The casement is now braced via the glazing unit and the striped packers. Now insert the dotted packers in no particular order.

    Top/bottom hung casements or direct glazed areas: The 'toe and heal' method of packing isn't needed for direct glazed areas, dummy sashes or top/bottom hung casements. For these situations all you need to do is pack the bottom so the glass edge spacer is balanced all the way around the glazing unit with the edge of the glazing rebate. Then pack the sides and top.

    NOTE: You may find that the glass leaves are not quite level with each other. This is down to the glass merchants working to certain tolerances which gives rise to this. Most of the time it is easily dealt with. The foam glazing tape is not load bearing; this is one of the reasons why packers are needed. Also the glass needs to be packed so that the warm edge spacers in the perimeter of the glass are as level as they can be with the edge of the beading.

  6. 5) Now you have to remove the lining from the glazing tape by pushing the glass slightly off the glazing tape (so as to not disturb the packers) creating just enough room to access the lining and pull it off. Now push the glass firmly onto the glazing tape in several places at which point it will be stuck.
  7. 6) If there are imitation glazing bars you will need to firmly push the bars onto the glass. This is because the 21x1mm imitation bar tape only properly activates under firm pressure.

NOTE: Filling the glazing rebate with silicon is detrimental to the window. It will block of all ventilation and reduce the life span of the window so please use packers only.

Installing the Beading

The side beads may appear too short but they are not. See 'Installing the bottom bead' further down the page. There are different beads for different places on a window. There are side beads which have mitred ends. There is the bottom bead and the top bead both of these beads do not have mitred ends like the side beads. The first beading to install is the top and bottom beads and then the side beads.

Installing the top and bottom bead: Using the 10mm by 2mm foam glazing tape stick it to the top of the bead flush with the bevel as in the first photo below. Peel back the lining and then apply the bead to the top of the glass. The bead should fit neatly all the way across the glass touching the sides of the sash.

On the bottom bead, you need to seal the faces of the bead against the frame using an appropriate colour silicone/mastic as pictured below. This prevents water getting into the glazing rebate and to the end grain of the bead itself.

Pinning the bead: Using a tack hammer, nail panel pins into the bevel of the bead to help hold it down. These panel pins must at least 25mm long and be made from sheradised steel or, better still, stainless steel to prevent rusting. Space the panel pins at approximately 300mm. Don't nail within 40mm of the ends otherwise you could split the bead, unless you drill a pilot hole. You need to punch the head underneath the surface of the bead and fill with something flexible such as teknoseal 4001. Paint over the filler.

Installing the side beads: These beads have mitred ends and the angle of the mitre is the same either end. Apply the 10 by 2mm foam glazing tape to the bead in the same way as the top and bottom bead and stick it to the glass making sure one end of the bead is touching the top bead. There is a gap of about 3mm between the other end of the side bead and the bottom bead; see the photo below, circled in red. This is to prevent the end grain of the side bead sitting in water on the bottom bead. Then pin the bead.

Installing the imitation plant on bars: The window can be vertical or horizontal to fit the imitation plant on bars. The temperature must be above 10 degrees centigrade to carry out this procedure. Clean the entire glass panel using methylated spirits. Using the 21 by 1mm foam glazing tape, pull it off the roll and apply it to the back of the imitation bars using the same method as you did with the tape in the glazing rebate and cut it to the exact length of the imitation bars. Now pull back 25mm of the lining tape from the ends of the imitation bars and place it in position on the glass very lightly so you can re-position it if you have to. At this point only the 25mm ends of the bars are lightly stuck to the glass. Make sure that the side ends of the bars are about 2mm away from the side beads of the sash or direct glazed area. This is an expansion gap and should not be filled. The top ends of the bars can be touching the top bead of the sash or direct glazed area in the same way that the side beads of the sash are as there is such a large expansion gap at the bottom of the bars. The bottom end of the imitation bar should be about 6mm from the bottom glazing bead to match the side beads of the sash or direct glazed area. This gap must not be filled. Now pull the rest of the lining away from under the imitation bars to adhere all the bars to the glass. Press down firmly along the bar in all the places on the bar several times (each time longer the last of up to 30 seconds) to activate the adhesion. The adhesion is only properly activated when firm pressure is applied. This is different to the other foam glazing tapes as they have instant adhesion.

Installing a fully finished glazed wooden window

Building regulations are constantly changing with how windows are to be installed and it is crucial that you have ascertained the correct method before ordering the windows as the requirements actually affect the design of the window. These regulations are mainly to help stop cold bridging from the outer wall to the window frame and into the dwelling which improves the overall thermal performance of your house. Your local building control officer will tell you what is required and will supersede any of the following if different.

To secure the window in the opening steel straps(pictured below) have to be screwed to the outer face edge of the jambs and then screwed into the inner wall. Usually we would recommend three straps to each jamb that measures less than 1200mm.

No fixings are required for the head and cill of a window as long as they are not more than 1800mm wide. If they are then one fixing in the middle maybe required for widths up to 3600mm. There is talk of the window needing to be inset into the insulation of the cavity or wall by 30mm which you will have needed to ascertain before ordering your windows as this will affect the size of your cill if you have one. Make sure that there is equal spacing all around the window and none of the window is actually touching the brick work by using packers. There should be a minimum gap of 5mm all around the window. Then you are supposed to create a thermal envelope in the gap between the window and the wall by squirting expanding foam into it. If you are going to do this then make sure you don't get it on any exterior brick work as it is very difficult to remove and it makes a terrible mess. We would recommend perimeter pointing before application of foam as the pointing will contain the foam and stop if expanding out onto the external brickwork. This foam will help secure the window into the opening so it might be a good idea to screw the strapping all around the perimeter edge of the window, but well away from the outside edge, to form a key for the foam to grip to. The foam is obviously best applied from inside the property but if you have to apply it externally then line the wall with ducting tape in case any foam leaks onto it. If you have perimeter pointed already and you need to apply foam externally you will need to drill small holes in the pointing (that you will have to repoint later) so you can insert the foam nozzle tube. After the foam is set, remove the packers which could also cause cold bridging.

You will probably need to use a specialised foam gun, like the one pictured below, as opposed to the disposable canister type. The reason being that the disposable canister type comes with a nozzle tube(approx 10mm in diameter) that will probably be too large to fit in the gap around the window. The specialised foam gun comes with a variety of nozzles tubes which will go all the way down to 2.5mm in diameter.

The foam forms such a tight bond between the window and wall there is an argument that the straps aren't necessary. In some countries they rely purely on the foam to secure the window without any straps. The big point about foam is that it isn't classed as load bearing so building control will condemn it if not being used in conjunction with straps. The problem with using straps is when the property is already plastered and finished on the inside. The home owner isn't going to be happy with plaster or tiles being hacked off their walls to make way for the straps.

Perimeter pointing is basically sealing the edge perimeter of the window to the wall, see photo below, area circled in red. It is a bit of a grey area because traditionally mastic and mortar was used but these substances can cause cold bridging so you will have to check with building control what is acceptable. Make sure that whatever you use for perimeter pointing is over paintable unless it's mortar. All of the above must be confirmed for current compliance of building regulations with your local building control. We will not be held liable for incorrect information that may have been given above.

Traditionally, of course, the installer of a window would use frame fixings instead of metal strapping to secure the window by drilling straight through the window jambs and into the outer brick work and then inserting the frame fixings. Frame fixings are basically a large screw and plastic plug. The plug goes into the wall and the screw tightens into it clamping the window jamb in place. The screw heads are then filled over and painted. This method is still widespread today but ever changing building regulations will probably make this unacceptable in the near future. Also, this method is not practical for most refinished glazed windows because that jamb is often inaccessible.

Manoeuvring a window into its opening

Manoeuvring a window into its opening can be very awkward as they are so heavy. The straps will have been fastened to the window before inserting it into the opening otherwise it will be impossible to fit them afterwards. If the opening is accessible from the inside this will make it a lot easier than trying to access it from the outside. To access the opening from the inside there has to be no plaster or obstructions on the inner wall so the window can pass straight through the opening and into position. Two people will be needed to lift the window in this way. If there is plaster on the inner walls and the windows have to be fitted from the outside then the ground floor windows may be easily accessible but the higher floors will need a raised platform to work from like scaffolding. The window will have to be lifted onto this platform in some way using several people or a crane of sorts. The window could also be taken to its opening on the inside of the building via the stairs and simply fed through the opening from the inside and onto the platform outside before being lifted into place.

Manual handing of wooden windows and storage

Handling of wooden windows always needs at least two people unless unglazed then maybe one person will do. Glazed windows can be very heavy and are easily damaged unless proper precautions are taken. Do not lift them by the casements as this will put all the weight on the ironmongery which may damage it. Store the windows in a cool dry place. Don't lay them one on top of each other as this could damage them. Always lean them upright. Remember that timber can dent and the finish can be scratched very easily so always put them on timber laths as direct contact with concrete or masonry could damage them.