How to replace a double-glazed window in plastic windows

Recommendation points

• Reasons for replacing a glass unit
• How to choose a glass unit for replacement, size matching
• Get the profile out of the opening or not
• How to properly tear off the glazing bead
• The process of replacing a double-glazed window in fixed and opening sashes
• Re-installation of glazing beads

The need to replace a double-glazed window in PVC windows may arise not only if the glass is damaged. Over time, plastic windows can greatly lose in performance. Do not rush to change the entire window. Replacing a double-glazed window with your own hands is not difficult, and our tips will help you do it.

Reasons for replacing a glass unit

In addition to damage to the glass unit, there are a number of common cases when replacement may be required. The first of these is the installation of PVC windows with one glass for the primary glazing of the construction site. Sometimes it is possible to replace obsolete packages with more modern ones if the characteristics of the profile itself are satisfactory. For example, an increased noise level may serve as a reason for replacement. You may also want to replace old double-glazed windows with energy-efficient K-glass or I-glass..

In some cases, a glass unit fails without visible signs of destruction. For example, if a chamber injected with argon has lost its tightness, condensation is likely to form on the glass. Air chambers in which the metal frame is damaged have the same symptom, in which case the silica gel will begin to dissolve and leak into the profile with a yellowish resin.

How to choose a glass unit for replacement, size matching

Before placing an order for a new double-glazed window, you need to clarify the dimensions of the old one. This can be done without even disassembling the window; it is enough to measure the distance between the outer joints of the glazing bead and subtract 15 mm from the value. Usually, manufacturers of double-glazed windows make their sizes in multiples of several centimeters, so you are unlikely to go wrong.

Length and width are not the only indicators. If the thickness of the glass unit does not match, you, at best, will be forced to purchase a suitable glazing bead, and at worst, a suitable PVC profile. The easiest way to clarify the thickness of the double-glazed window is in the passport for the windows or on the sticker, if you carefully removed it. Otherwise, invite a familiar PVC window specialist, he will immediately determine the type of camera and the standard thickness for it.

Irregular insulating glass units require removal of the template. In this case, you will have to remove the glass unit from the frame, lay it on a sheet of Whatman paper and circle with a sharp blade, repeating the shape. However, an experienced measurer will always help you in determining the exact dimensions and patterns..

In some cases, when only one of the glass is damaged, it makes sense to make repairs by sending the glass unit to the window manufacturer’s factory. This is especially useful in the case of expensive double-glazed windows. Repair is carried out in a period of three days to two weeks, during which time you can install single glass in the frame or tighten the opening with plastic wrap.

Get the profile out of the opening or not

For a simple replacement of a glass unit, complete dismantling is not required; on the contrary, it is more convenient to work on an installed window. But there are exceptions.

The case, as they say, is out of the ordinary, but a broken glass unit may not be the work of hooligans. If the installation technology is not followed, if a low-quality PVC profile is used, or if the size does not match, the glass unit can simply be crushed inside the frame. In this case, the trouble may repeat itself even after installing a new glass unit..

You can independently identify the problem by examining the inner cavity and folds of the PVC profile. If there are kinks on the longitudinal stiffeners, or glued joints have dispersed, the window must be repaired or replaced. If in doubt, invite the installation wizard, he will give further recommendations.

How to properly tear off the glazing bead

To tear off the glazing bead, you need to insert a chisel into the gap between it and the frame, directing the bevel of the blade towards the glass. Hold the chisel strictly perpendicular and apply a few light blows with a mallet until the glazing bead is 2–3 mm away. Then tilt the chisel slightly outward and widen the gap with a series of blows. Knock down the glazing bead until it is completely out of the groove..

Start dismantling by removing the longer glazing beads: they are the most flexible and easier to come out of the grooves. Undermine them, starting from the center, and gradually work towards the edge. When you can grab the edge of the glazing bead with your hand, just pull it towards you and to the side, it will easily come off.

Remove the upper glazing bead last so that the glass unit does not fall out of the opening without permission. It is optimal to use an evenly sharpened chisel with a slightly blunt blade edge for work. Also, buy a hammer with plastic or rubber heels..

The process of replacing a double-glazed window in fixed and opening sashes

If the glass unit is broken, it can crumble when removed. To prevent this from happening, cover the surfaces of the outer glasses with strips of tape, first along the perimeter, and then crosswise.

Usually the glass unit is loosely installed inside the frame and will fall out by itself after removing the top glazing bead. If it is pressed, pull on one of the plastic spacers, or pick up the edge of the glass unit with a knife.

Carefully remove the glass unit from the opening, if it is too heavy, call an assistant. Clean the folds and profile cavity from glass fragments and dust. When working, be sure to use gloves with a rubberized grip. We also recommend not to neglect protective goggles..

Insert the new glass unit with the bottom side, then lift it vertically. In blind openings, it is necessary to put two straightening plates made of plastic between the glass unit and the lower seam. If desired, you can fix the double-glazed window in the opening with two more installed on top.

When installed in an openable sash, four plates are placed diagonally between the glass unit and the profile: 10 cm from opposite corners. The sash must be installed for ventilation and the double-glazed window must be horizontally aligned, evenly spreading the spacer strips remaining after removal under the bottom end.

Some double-glazed windows inherit the principle of sealing from wooden euro-windows. But there is a difference: instead of pouring a silicone sealant between the frame of the glass unit and the profile fold, a silicone tape of different thicknesses is inserted. The installation process is difficult, since you must first measure the thickness of the gap and select the desired thickness of the gasket. Experts always have a supply of tapes of different sizes with them and carry out the installation in one day.

When installing a double-glazed window onto a tape, it must be continuous along the entire perimeter. Therefore, to begin with, they cover the glass unit with tape as tightly as possible and cut it at an acute angle, leaving a gap of 3-4 mm. The tape is inserted into the lower profile cavity and a glass unit is placed on it. Raising it vertically, the tape is tucked into the seam with a blunt smooth plate.

Re-installation of glazing beads

Start attaching the glazing beads back to the process of removing them, that is, starting with the shortest ones. Place the glazing bead approximately in the middle of the opening and hammer it into the groove, moving from one edge to the other.

When installing long glazing beads, first drive them into a corner, moving the already installed strip to the desired distance. Then wind the glazing bead in the lower corner so that it spreads out in the opening. Do not snap on the first glazing bead until you have installed the second. With this sequence of installation, the glazing beads are well pressed at the joints and do not form gaps – cold bridges. To avoid breaking glass, use a rubber-coated hammer.