How to fit uPVC Windows

The fitting or installation of uPVC windows is a relatively straight forward process but we would like to point out that the information provided in this article is designed as a helpful insight.

Always consult with a window industry professional if you need help your installing windows in your property or project. The Genesis Installer Network is a great place to start and a full list of the installers is available here. Lets get into how to fit uPVC windows.

uPVC double glazed windows often have these components

  • The frames including the openers
  • The Cill with end caps
  • The Glass
  • The Glass beading

Some of the materials you are likely to need are:

  • Cement
  • Mastic
  • Sealant
  • Silicone
  • Packers & Spacers
  • Hammer
  • Screwdriver
  • Chisel
  • Fixing screws and plugs
  • Cleaning fluid

How to fit uPVC Windows

Depending on the size of the window and your manufacturer, some of these parts may or may not have been already assembled. In most cases the cill is sent as a separate item along with the end caps and the window itself will either be fully glazed with the glazing beads inserted or may be supplied unglazed. In this case you will need to glaze the window by inserting the glass and tapping the glazing beads into position. Figuring out how to fit uPVC windows can be tricky business.

Carefully extract your old windows and ensure that you minimise damage to the plasterwork and walls, in doing so you can save yourself a lot of decorative remedial work after the windows have been installed. Do take care to avoid damaging or pulling out the vertical damp proof courses as you remove the old window frame. If you do happen to damage of remove these you will need to replace them before commencing the installation of your uPVC windows.
If your new windows need to have trickle vents you will need to make sure that they are not going to impinge on cavity wall where the head of the frame is inserted into the opening. To avoid this being a problem you can have your windows designed to have a large outer frame or have the trickle vents inserted into the opener or sash. Trickle vents are used for ventilation and usually a building regulation requirement on new build properties. Older renovation works tend not to have them unless the property has condensation or ventilation problems.

The glass otherwise known as double glazed units are two sealed panes of glass separated by a warm edge spacer bar filled with silica crystals which absorb any moisture ensuring that no condensation can build up inside the glass unit DGU. Genesis Collection provides a 10-year warranty on double glazed units should you encounter a problem. The glass is manufactured to fit easily into the frame you order. The manufacturer will take care of the glass sizes based on the frame sizes that you have asked for. The double glazed glass units will be manufactured to a size that allows enough space for the fixing screws to be inserted.

When installing the glass unit you will need to position it so that it is equally spaced from each edge of the framework using spacers or packers. Where the glass unit has any form of decorative Georgian bar inside the glass unit you will need to take particular care to ensure these are positioned perfectly vertically and horizontally for the best appearance.

If the beads were installed when you took delivery of your uPVC windows these can easily be removed using a sharp implement like a scraper or chisel. This will enable you to locate fixing points on the inside of the outer frame and give you an understanding of the rebates that house glass.

The window frame is generally supplied separately to the cill which is usually cut to length and is sometimes a little longer than needed which can prove useful in some situations. The cill should be supplied with end caps designed to finish the open ends of the cill and these can be secured in place using glue or specialist PVC adhesives.

To begin the installation ensure the bed on the outer brick skin is clean, free from debris and level. Then place the cill on top of a sand, mastic or cement bed. Next apply a bead of silicone is to the top face of the sill upon which the window frame should be placed. The internal edge of the sill has a small upstand against which the window will sit and it is very important that this is sealed with silicone to prevent water ingress. The gap at the front between the window frame and cill does NOT need sealing with silicone as it should be left open to allow rainwater to escape from drainage holes in the bottom of the frame out over the cill.

It is important to position the window frame using packers or spacers, which are available is a variety of sizes, so that it is sitting as level and square to the opening as possible.

Choose a solid area of wall and drill through from the inside the frame through to the brick or stonework.

Countersink the fixing hole taking care not to damage the outer wall of the pvc window frame.

First insert the plug in the countersunk drilled holes. This may be a little tight and you may need a hammer to get these fully inserted. Then simply secure the window frame using frame fix screws and driving them from the inside of the frame into the plug in the wall.

Ideally you should have your fixings close to where you have used the spacers to position the window initially or in places where the frame is already connected to the reveal. This will ensure that the window frame isn’t pulled out of shape when the fixing screws are tightened

The next stage is to glaze the window.

With the aid of assorted packers and spacers position the glass so that it is square to the surrounding frame. As mentioned earlier this is particularly important if the window has internal decorative bars to ensure they are displayed in line both horizontally and vertically.

Once you are satisfied that the glass is in the right position you can secure the glass in place by inserting the beads. You should insert the shortest sections first as the longer sections are more flexible and easier to tap into place. If the rubber gasket is sticking on the glass use some diluted washing up detergent to lubricate.

The next to last step involves the sealing in of the window frame to the brick or stonework from the outside. This can be done using mastic, sealant, silicone or render depending on the style of property or look you would like to achieve. Internally you may need to make good any damage to plaster work that might have occurred and tend to décor if this has been affected.

Finally remove any labels and protective tape, clean glass and uPVC and take a step back and admire the installation of your windows.

In this article we have covered the installation of a casement window, but as can be seen in the Genesis Collection there are many more styles available which are suitable for both new build and renovation properties.

Now you know more about how to fit uPVC windows, you should see the range of windows that we have, visit our Genesis Collection Windows range.

Please note the instructions detailed within this article have been provided with the best of intentions but we are unable to guarantee complete accuracy and as a result no responsibility can be taken for the outcome of any work undertaken.