Choosing the correct window sizes to suit block work may appear at the time to be a relatively minor consideration, and as such is often overlooked. However this is not the case. Correctly specified window sizes will result in substantial savings in both time and money.
Because concrete block are designed to work in modules of 200mm, you should design your windows to work the same way.
Window widths should be in modules of 200mm plus 10mm (Joint Allowance).
For Example -
Window heights should be in module of 200mm plus 100mm (Sill Block if used) plus 10mm (Joint Allowance).
For Example -
While it is not absolutely necessary to follow the above sizing for windows, doing so will save both time and money. If however, you wish to use unusual sized windows it is possible to do so. It just requires that the blocks are cut to custom sizes to suit your windows.
Make sure you specify the correct blocks for window openings in your quantities. These blocks have a groove down one side to accommodate the flange on the window frame.
You will need to remove the top flange on the windows as the bond beam (lintel) blocks do not come with a groove for the flange. This flange can be removed easily if required.