Burglar bars vs trellidors: which does your house need?

The short answer

• Fixed burglar bars suit windows you do not need to climb through or open fully: bathrooms, kitchens, passages, garages and most living-room windows.
• Expandable security gates (trellidors) suit openings you use every day — front and back doors, patio sliders and wide openings — and any window you want to open completely.
• Every bedroom should have at least one opening that can be unlocked from inside in an emergency: an openable grille, or a security gate with the key kept nearby.

Fixed burglar bars

Burglar bars are welded steel grilles fixed over a window, usually inside the frame or on the wall around it. With no moving parts they are strong, low-maintenance and usually less hardware per opening than an expandable gate. Designs range from simple straight bars to patterns that match your gate or balustrade.

The downside is that they are permanent. If every window is barred, a fire becomes very dangerous. That is why we build emergency-release or hinged, lockable grilles for bedrooms — see security & burglar proofing.

Expandable security gates (trellidors)

An expandable security gate is a steel lattice that folds to one side and locks across the opening. You get full access when it is open and a solid barrier when it is closed — ideal where you want the door or window open for air during the day.

The downside is moving parts: top and bottom tracks, pivots and a lock. They cost more per opening than fixed bars and need occasional cleaning and lubrication. Built in steel and made to the exact opening, they last well — see our steel security gates.

Opening by opening

Steel or aluminium?

For security we build in steel. It is stronger against forced entry and lasts longer under impact. Aluminium is excellent for the doors and windows themselves — light, and it will not rust — which is why many homes pair aluminium doors with a steel security gate in front.

What affects the price

• Size and number of openings. Repeated sizes can be built in one batch, which saves time and cost — useful for rental rooms.
• Type. Expandable gates carry more hardware than fixed bars.
• Design. Plain bars cost less than patterns or laser-cut inserts.
• Lock and hardware. Cylinder type, number of locking points.
• Finish. Primer only, or powder-coat in charcoal, black, bronze or white.
• Fixing. Into brick, into a steel or aluminium frame, or onto a new sub-frame.

Keeping them working

1. Brush sand and grit out of expandable-gate tracks every few weeks, especially after windy days.
2. Put a drop of light oil on pivots and the lock from time to time — not grease, which traps dust.
3. Touch up scratches in the paint quickly so rust does not start.
4. Check the wall fixings once a year and tighten or replace any that have loosened.

Securing a plot with several rental units? Our Mogoditshane page has a checklist for landlords.