How to measure a doorway for a security screen door

Measure the opening, not the old door

Measure the hole in the wall, jamb to jamb and sill to head, not the door hanging in it. A door is smaller than the frame around it. Corinthian Doors, an Australian door maker, lists a 2040 by 820 mm entrance door in a single frame of 2100 by 866 mm on its frame table. So a door size, a frame size and an opening size are three different numbers, and only the opening tells you what a security screen has to fill.

An old screen door is a poor guide for the same reason. It may have been a stock size packed out to fit, or the frame may have moved since it went in. Take fresh measurements of the opening as it is today.

There's one more step for a security door. The figure a door is built to is a make size, which is the opening less a set of deductions. One DIY supplier's measure guide says its factory builds to the make size you send and does no deductions, so the buyer has to take them off and get them right. On a made-to-measure job, the fabricator who measures the opening does that work.

Width, height and square: the three checks

Take three widths and three heights, then compare them. The steps below follow the hinged door measure guide from OnlineSecurityScreens.com.au, a supplier of DIY security doors. It's a useful way to record an opening even if you never order a kit. Use a good steel tape and record millimetres.

If the readings don't match, the opening is out of square, and that's common. ScreenGuard says very few homes have perfectly standard, square openings, and that out-of-square or non-standard openings need made-to-measure fabrication rather than stock sizing.

1. Width at the top: measure jamb to jamb at the head of the opening, then again 150 mm down.
2. Width at the centre: measure jamb to jamb halfway up the opening.
3. Width at the bottom: measure jamb to jamb at the sill, then again 150 mm up.
4. Height in three places: measure sill to head on the hinge side, the lock side and the centre.
5. Keep the smallest height, and the smallest reading at the top and at the bottom. A door sized to the largest figure won't fit where the opening is tightest.
6. Compare the widths. That guide allows no more than 7 mm between its top and centre widths, or its bottom and centre widths. Any spread means the jambs aren't quite parallel, and past 7 mm that guide's door won't suit the opening.

Reveal depth and where the screen will sit

The reveal is the depth of jamb in front of your closed timber door, and it decides how a hinged security door mounts. In the OnlineSecurityScreens guide, the security door swings out, hung on the outside of the jamb. It needs somewhere to sit and enough room in front of the timber door for both handles.

That guide sets out the numbers for its own door. It needs a reveal of 20 mm or more, or no reveal at all. From 23 to 26 mm it adds adhesive mohair; from 27 to 35 mm it adds hinge packers, adhesive mohair and an extended striker; past 35 mm, or with no reveal, it uses a stop bead. It also checks the gap from a straight edge across the jamb to the timber door: a minimum of 53 mm, with 56 mm or more recommended, so the screen's handle clears the door behind it.

Those figures belong to that product. Other hardware has other numbers. ScreenGuard says that because every door is fabricated for a specific opening, the only accurate quote is one based on your actual doors and windows.

Standard door sizes exist, but made-to-measure security screens are built to the opening

Entrance doors come in standard sizes. The security screen doors we build don't. Corinthian Doors lists its single entrance frames for doors 2040 or 2340 mm high and 820, 870 or 920 mm wide. Those are door sizes, though, and Corinthian also says it can tailor-make entrance frames for any size opening.

On the screen side, ScreenGuard says there's no fixed size range. Every ScreenGuard door is custom-built to the exact dimensions of the opening, and measured, fabricated and installed by a licensed local supplier rather than cut down from a standard size.

So a common door size tells you roughly what to expect, and not much else. Your opening may not match any catalogue, and ScreenGuard says very few homes have perfectly standard, square openings, especially older homes. Every door and screen we supply is made to measure in Cairns rather than supplied in a stock size, so the figure that counts is the one taken at your house.

Hinged or sliding: what changes in the measure

Each door type adds its own checks to the measure. ScreenGuard says sliding doors suit patios and balconies where a swinging door isn't practical, and hinged doors suit single front, side or back entrances. Before you measure, note which type each opening needs. Not sure which type suits a doorway? Our guide to hinged vs sliding security doors matches a type to each opening.

• Hinged: walk the swing path. The OnlineSecurityScreens guide lists lights, awnings, walls, stairs and uneven ground or concrete as things to note.
• Hinged: stand outside and choose the lock side, left or right. That guide sets the screen's lock height from the handle on the existing timber door.
• Hinged: check how the existing door hangs. That guide's kit suits a timber door hinged on its edge, not a pivot door.
• Sliding: note the track the glass door runs on. ScreenGuard sets its sliders up with rollers for narrow or wide tracks.
• Sliding: note the full opening the slider will cover; we measure it on site the same way we measure every opening.

What happens at a made-to-measure visit

At a made-to-measure visit, we take the measurements ourselves, so your own figures are for planning and comparing quotes. We measure every opening on site. Older Cairns houses are rarely square, and a stock size leaves gaps, so the door is built in Cairns to the figures taken at your house, in whichever of our four ranges you choose: SCREENGUARD 316 marine grade stainless mesh, PERFGUARD perforated mesh, Diamond Grille or Colonial Casting. Then we come back and fit it. There's no showroom, so the measure is where the job starts.

The visit also shows up anything that changes the job. ScreenGuard's cost guide says a square opening in good condition is quicker and more affordable to fit than one needing old frames repaired or reinforced, existing screens or grilles removed, or a sill extended. If an opening needs any of that, it belongs on the quote, not on install day.

Keep your own numbers handy anyway. Two quotes measured from the same opening should land on similar sizes. If one is well off the other, ask why.

Measure it yourself, but leave the build and fit to a licensed installer

Measuring is a safe job for a homeowner. Building and fitting one is a different matter: the NSSA advises against doing it yourself. The National Security Screen Association (NSSA) says compliant security screen doors are made and installed to very tight tolerances with specialised fixings, and that while you may get a screen up and working, it may not provide proper security. It also says that in many states security screen installers need to be licensed. In Queensland, the QBCC lists fabricating and installing security screens and doors in the scope of work for its glass, glazing and aluminium licence.

ScreenGuard takes the same line: its doors aren't a DIY kit, and each one is custom-measured and installed by a licensed fabricator for fit, weather sealing and warranty coverage.

That's also why cutting a security door down isn't the fix for a door that's too big. ScreenGuard builds to the measured opening rather than cutting down a standard size. We work under QBCC licence 1199847, published so you can check it on the public register before you book.

Next step: match a door type, then book a measure

Once you've measured, decide which door type suits each opening. Our guide to hinged and sliding security doors compares space, cost and upkeep, and choosing a security screen in Cairns covers mesh and ranges. Our security doors and screens page shows what we build.

When you're ready, list your openings through the quote form on our contact page, with your own figures if you have them, and we'll measure at the house. We work across Cairns and the northern beaches: see security screens across Cairns or check the areas we serve.