How to measure for security grillesVIEW GALLERY
Choose the illustration that matches your opening and the position where the grille will be fitted. Use centimetres throughout, including any decimal measurements, and follow the instructions for that opening rather than using a general window-measuring rule.
The recessed arrangements shown assume outward-opening windows or doors. If yours open inwards, or there is no suitable recess, check the face-fixing guidance and speak to us if you are unsure. Handles, hinges and nearby fittings can affect the available space.
For a bay window, use our photo quote service so that we can see the layout. Photographs also help with combined door-and-window openings or any arrangement that does not match the illustrations. They support the measuring process; they do not replace confirmed dimensions.
DOOR RECESS
HEIGHT
Floor to underside of lintel
Measure at the point where the grille will be fitted. This is usually as close to the frame as possible allowing for any handles etc. Measure in at least three places. If there is a carpet, lift and measure from solid floor underneath. Take the shortest measurement.
WIDTH
Top and bottom of the recess
Measure at the top and the bottom of the recess. If there is skirting board in the recess, measure above this - it can be removed or trimmed out on installation. Take the widest measurement.
WINDOW RECESS
HEIGHT
Sill to underside of lintel
Measure at the point where the grille will be fitted. This is usually as close to the frame as possible allowing for any handles etc. Measure in at least three places. Take the shortest measurement.
WIDTH
Top and bottom of the recess
Measure at the top and the bottom of the recess. Take the widest measurement.
FLAG
The door and window will have separate grilles (this only works if both door and window opens outwards).
HEIGHT
WIDTH
T SHAPE
The door and windows will have separate grilles (this only works if both door and window open outwards).
HEIGHT
WIDTH
FACE FIX
This method of measuring is applicable where there is no recess or for most inward opening doors and windows.
HEIGHT
Door and window height
Measure the height of the door from the step to 5-10cm above where the recess finishes. With a window you may need to measure 5-10cm above and below the recess.
WIDTH
Width of recess + a percentage
Measure the width of the recess and add 10% to either side for a double sash (locking in middle) and 20% for single sash grille (locking on one side).
We will calculate the additional cost of the frame.
Frequently Asked Questions
How do I measure the height of a recess?
Start with the illustrated instructions for either a door recess or a window recess. The measurement points differ, so do not apply a door measurement to a window. Take the readings at the proposed grille position and follow the relevant instructions on which measurement to record.
How do I measure the width of a recess?
Use the width instructions for your opening and record the readings at the positions shown. Follow the guide’s rule for choosing the final measurement. If the sides are uneven or an obstruction affects the fixing position, contact us for help; photos are optional. Our team checks your measurements with you after you order and before manufacture.
How do I measure for face fixing?
Use the face-fixing section below the illustrations. It includes allowances that depend on the grille arrangement, so a recess measurement alone is not the finished requirement. Do not add a guessed allowance or combine rules from different sections. Ask us to confirm anything that is unclear.
What should I do with a bay window or unusual opening?
Send a photograph showing the complete opening, including the surrounding wall or frame, handles and any relevant obstructions. Bay windows and combined openings need particular care. We can help you identify the right measuring approach before you submit the specification for manufacture.
Which units should I use?
Use centimetres consistently for the measurements you submit. If you have already measured in inches, check the conversion carefully rather than mixing units within the same order. If you are uncertain, send the original readings and explain the units before the specification is confirmed.
How do I measure a flag or T-shaped opening?
Use the matching flag or T-shape illustrations and record the window and door dimensions as directed. Check the opening direction against the conditions shown in the guide. If your arrangement differs, send photographs and ask for advice rather than adapting the calculations yourself.
Why does the fixing position matter?
Your grille is made to measure for a particular opening and installation arrangement. Changing the proposed fixing position can change the required dimensions or clearances. Confirm where it will be fitted, follow the guide and check the measurements again before placing the order.
What happens once I have my measurements?
Confirm the opening type and configuration, then use the self-install ordering route. Review the installation instructions before buying so you can plan the work. If anything is uncertain, contact the team before the order enters production.