One way vision mesh: how it works, and what it won't do

How one way vision mesh works: the brighter side gets seen

One way vision mesh depends on a difference in light, together with the pattern of the mesh. Starline Security, which makes one way vision mesh screens, says visibility is partly determined by the lighting: whichever side of the mesh is lighter at the time is the side that's easier to see. During the day the street, the yard or the neighbour's driveway is the bright side, so the outside is the more visible side and you can look out at it.

Starline describes its mesh as an expanded aluminium sheet whose vision from one side is better than from the other. Another supplier says one way limited vision mesh, also known as DVA mesh, has a pattern designed to restrict visibility in one direction while still allowing airflow and the view out.

No one way mesh is perfect. One supplier says on its own product page that DVA is never 100 percent one way, and that there is usually at least a silhouette somewhere. The conditions it needs are dark inside and light outside. So think of it as mesh that makes seeing in much harder by day, not as a solid wall.

After dark with the lights on, the effect reverses

At night the light rule runs the other way. Once it's dark outside and your lights are on, the inside becomes the bright side. Starline says it's easy to see inside at night when the lights are on, and one supplier puts it in one line: if the conditions are opposite, the result will be opposite.

That matters most for rooms you use after dark: a lounge that faces the street, a bedroom near a neighbour's window, or a bathroom on a side path. Starline says the mesh still breaks up shapes and movement more than a standard flyscreen does, but one way vision mesh won't hide a lit room in the evening.

The fix is straightforward. Starline's advice for night time privacy is to pair the mesh with blinds or curtains, so you keep the daytime benefit and close up after dark. If a room is mostly used at night, plan the window coverings and the mesh together rather than expecting the mesh to do both jobs.

A privacy mesh, not a security product in itself

DVA is a privacy mesh and it is not a security product in itself. That's how we describe it on our own range of mesh, and it's the most important thing to know before you buy. A DVA panel changes what people can see. It isn't what stops someone getting through the door or window.

Seconline, which makes and sells screens, describes standard DVA as a very light weight product that was not considered a high security product and needed an additional grille to support it. Some suppliers now sell heavier one way meshes as security mesh in their own right. That's a different product from standard DVA, so judge it on its paperwork rather than its name.

The paperwork starts with the label. The National Security Screen Association says security doors must be supplied and installed with a compliance label, and if a door isn't labelled, it isn't a security door. The current Australian Standard for security screens adds that a security screen isn't intruder-proof, and that how secure one turns out depends on the screen, the way it's fixed to the building, the locking hardware and the strength of the frame behind it. A privacy mesh can't stand in for any of those four.

How we pair DVA with a security grille

We fit DVA combined with a Diamond Grille or a Colonial Casting screen rather than on its own. The grille or the cast panel does the security, and the DVA does the privacy. So a one way vision screen door from us is a Diamond Grille or Colonial Casting door with DVA combined into it, not a DVA sheet on its own. By day, you end up with one door or window that handles both jobs, instead of a security screen plus a separate privacy treatment.

The two grilles suit different houses. Diamond Grille is our cost effective range, a visible diamond pattern rather than a fine mesh. Colonial Casting is the decorative one, with cast panels for a front entry or an enclosed patio in modern and heritage designs. Without DVA, both carry fibreglass mesh as standard, which won't rust, rot or corrode and keeps the insects out. With DVA in the screen, what stops insects is whatever sits behind it, so ask about that when you get a quote.

If you're still choosing the security side, our guide to diamond grille versus stainless steel mesh sets out what each one gives and gives up. Our range of mesh puts DVA beside the other four meshes we fit.

Where one way vision mesh suits a Cairns house

One way vision mesh earns its place on openings that face people during the day. As one way vision window mesh, it suits a bedroom or bathroom window that faces a neighbour or a footpath, which is where our range of mesh points it. One supplier lists street facing entries and ground floor windows as typical uses.

The same question comes up across our suburb pages. In Smithfield, we point to street facing rooms and ground floor bedrooms near the major centre as the place for a reduced visibility screen such as PERFGUARD perforated aluminium. In a Cairns North unit block, a balcony slider is in view of the street and of every other balcony. Openings like these are the ones to think about for DVA with a grille, or for perforated aluminium.

It also keeps the airflow, so you can leave a door or window open for the breeze without the room being on display. Starline says rooms still get natural daylight through it, and that some owners find it softens glare.

For a west facing window where the afternoon sun is the main problem, look at perforated aluminium too. Our PERFGUARD screens use a 2 mm perforated aluminium sheet, powder coated black with 40 percent view through, and we list them for privacy screening and sun screening as well as security. Unlike DVA, PERFGUARD has passed the impact, pull, jemmy, knife shear and probe tests itself. The table below sets the three options side by side.

A sheet off the shelf or a screen made to measure

You can buy one way vision mesh as a loose sheet, but a sheet is only the infill. One supplier, for example, sells it in standard widths including 750, 820, 900 and 1200 mm at 2000 mm long. The sheet then has to be cut to the opening and held in a frame, and at least one supplier sells a separate clamp bar designed to hold DVA in place on an aluminium security door. Because it's an aluminium sheet, Starline notes it isn't flexible enough for magnetic insect screens.

The bigger question is what the sheet is going into. Fitting DVA to a door that was never a security door doesn't make it one, because DVA adds privacy, not security. If the opening needs to keep someone out, the grille, the frame, the lock and the fixing are what matter, and the DVA sheet adds none of them.

Our doors and screens are made to measure and manufactured in Cairns, so the DVA and the grille are built into a screen sized to your opening, not a stock sheet trimmed to fit. Every screen we make starts with a measure of the opening as built, because openings in older Cairns houses are rarely square. The measure is also where we work out which mesh suits your place, including how close to the water it sits.

If you're weighing a loose sheet against a finished screen, ask us for a quote and tell us which door or window you want to screen.

What to ask before you choose

A few questions settle most one way vision decisions, and they're worth asking any supplier, including us. If you'd like to see the security ranges first, our security doors and screens page covers each one, and our guide to fly screens versus security screens explains why the label matters. If keeping a clear view out matters more than privacy, compare SCREENGUARD stainless steel screens. We measure and fit across the areas we serve in the Cairns region.

• Which rooms need privacy after dark, and what blinds or curtains will cover them then?
• What does the security work in this screen: a labelled grille or cast panel, or nothing?
• Is the finished door or window labelled as a security screen, and can I see the test certificate?
• What sits behind the DVA to keep insects out?
• Is the screen made to measure for this opening, or a stock sheet cut to fit?
• Would perforated aluminium or woven stainless suit this window better?