Replacing a Bay window? Easy peasy right? Then how come we receive dozens of cries for help every year from builders that didn’t obey a few simple but essential rules for installing these highly popular features?
The installation time varies depending on the building you are working on. It may take between 2-4 hours per window for a replacement job and bear in mind, a bay is actually several windows.
It’s worth understanding the component parts of a bay windows as shown in this illustration.
Step 1 – Assessment and Measuring
When you complete the initial survey to detail the new window specification, it is vital that you first check that there are no concerns such as cracks in the brick wall before you proceed. Any cosmetic issues might conceal far more serious problems which should be dealt with before you start work on the removal and replacement of the window.
To measure, take dimensions of the existing windows point to point. You also need the internal angle of each section. Take the smallest measurements possible, as these will be the ‘tight’ sizes. This will allow tolerances that give space for expansion and contraction of the bay window frames.
Step 2 – Remove Existing Windows
Your assessment will determine if you need props. But if in doubt, prop it!
Double check that your new windows are the correct sizes before removing the old frames. Make sure all of the old windows are removed and leave as smooth an opening as possible – this will make fitting the new windows a lot easier.
Step 3 – Measure The Sill
When the aperture is ready, measure the angles for the sill. Bay posts come in two different variants: 90-degree and variable. With any variable degree bay post measure the angles for the sill. It’s vital that the angle is correct before cutting the sills on the windows.
Allow around 9mm for the bay posts, a measurement that may change due to the angle of your bay; always measure before cutting the sill. Also measure all corners of the bay just in case the angles are different.
Step 4 – Cut The Sill
Tip: remove one or both sashes to make the window lighter and easier to install. Place the window on its head, remove the sill, cut the angle of your bay and then re-attach the sill.
Step 5 – Frame Adaptors
Now the sills are cut to the right angles you are almost ready to install. Before placing the windows into the bay, fit frame adaptors to both external sides of the middle bay. Use 25mm self-tapper screws, one at the top and one at the bottom, then 500mm apart. Inspect the positioning of the frame adaptors; make sure the adaptor is touching the outer frame where the lip is on the frame adaptor. If it’s not touching the bay poles will not sit correctly later.
Take extra care when screwing the adaptor to the frame. You should make sure that the screws don’t penetrate into the sash chambers (marked in red) as this can affect the function of the window.
Step 6 – Place Windows In Position
Start by placing the middle bay into position, including packers under the outer frame. Throughout the process ensure the window is level, especially before fixing.
Remove the sash stops at the top and place two fixing screws to hold the window in place.
Repeat this process for the side windows also known as the returns. Again, make sure to include packers. Frame adaptors are not yet needed for the side windows.
Step 7 – Level Windows
Once all windows are in position, start with your highest point and use packers or 35mm architrave to pack the other windows to make all the windows level.
You may need to unscrew the fixing screws to level the windows (support the window if removing fixing screws!).
Step 8 – Bay Poles
When windows are level, attach the frame adaptor to the bay pole (make sure it is the opposite side to the frame adaptor that you have attached to the outer frame).
Ensure the ball and socket joint on the aluminium are in correctly. Do not fix screws into the bay until the internal side is checked. Before fixing any screws ensure the bay pole is centred all the way down the bay. Ensure the frame adaptor is touching the inside lip of the outer frame. When the bay pole and the frame adaptor are level, fix screws (45mm self-tappers) into the aluminium bay pole, one at the top and one at the bottom, then 500mm apart, fixing into the centre of the reinforcing on the window.
Check the inside after fixing to see if the bay pole has moved.
Step 9 – Final Fixing Screws
Once all windows and bay poles are in place check all levels. Remove sash stop at the bottom and place a fixing screw and fix final fixing screws in the top of the window. Also fix through the sill, and ensure the bay pole covers the screws.
Step 10 – Re-install The Sashes
If you removed the sashes they may now be re-installed. Ensure they are level and that each is fitted perfectly. Check the windows operate smoothly and correctly.
Step 11 – Finishing Touches
Install internal and external trim on the bay poles and tidy around the window ensuring no gaps. Then fix all additional furniture on the window such as pole eyes or D handles if requested. Perform one last check to confirm everything works smoothly. Pat yourself and the lads on the back.
For further information on Quickslide bay windows visit https://www.quickslide.co.uk/