The short version
- The angle is measured from the gate face. 0 degrees is flat in the face and closed. 90 degrees is square to the face and open.
- Lower angles give more privacy and less airflow. 45 degrees is the usual starting point.
- Overlap hides the gap between blades in the front view. A gap opens it.
- Set the blades out by overlap, by pitch (centre to centre) or by an exact count.
- Choose the blade by the job: flat or hollow bar for a blade fence, elliptical or aerofoil for a finer look, Z or chevron for screening.
- Blades can be welded, end-fixed into a side channel, or clipped to a carrier.
Angle: privacy against airflow
Picture the blade from the side. At 0 degrees it lies in the plane of the gate like a flat sheet, so nothing passes. As you raise the angle the blade turns toward the viewer, the front-view height of each blade shrinks, and light and air get through. At 90 degrees the blade is square to the face and you mostly see its thin edge.
The designer's Fit to frame choice picks the steepest angle at which the tilted blade still sits inside the frame depth, never past 45 degrees. A blade that is deeper than the frame at 45 degrees stands proud of it; the designer tells you by how much.
Privacy depends on where the viewer stands as well as the angle. With the standard tilt, a 100 x 16 flat blade overlapped by 10 mm hides what is behind it from the front and from below, and opens up to someone looking down at the gate from more than roughly 10 degrees. The readout under the diagram states this for your blade, from the front and from the back.
Overlap, pitch or count
Overlap or gap is the front-view distance by which a blade covers the one beside it. The largest overlap that builds depends on the blade size and angle, and the designer shows it. Pitch is the centre-to-centre distance, the figure suppliers quote. Count places an exact number of blades and spreads them to fill the opening.
By default the stack of blades is centred in the opening. Choose From the bottom or From the top to start the first blade a set distance from a rail, which is how a shop usually marks out a blade fence.
Choosing the blade
- Flat bar (for example 100 x 16): the simple, cheap choice.
- Hollow RHS (for example 65 x 16 x 1.2): stiffer for its weight, so it spans further before it sags.
- Elliptical and aerofoil: extruded sections with a finer profile that shed rain well.
- Z blade and chevron: thin sheet sections used to screen plant and equipment. The Z has a lip at each edge, the chevron is a shallow inverted V.
How the blades are fixed
Welded is the plain blade fence: each end welded to the stile or rail. End-fixed in a side channel puts a channel on each jamb and runs the blade into it, held by two self-tappers an end. Clipped to a carrier uses a punched channel the blades clip onto, so the blade stops at the channel mouth.
Channels and carriers are drawn as members of their own, listed in the cutting list, and the blades are cut shorter by what each takes. The channel has to be wide enough for the tilted blade, and the designer says so if it is not. They need a level frame.
Draw a louvred gate, fence or screen
Enter your opening, pick a blade and an angle, and CAD60 draws every blade with a dimensioned drawing pack:
Questions people ask
What angle should louvre blades be?
45 degrees is the usual starting point and CAD60's default. In CAD60 the angle is measured from the gate face: 0 degrees lays the blade flat in the face and closes the gap, 90 degrees turns it square to the face and opens it up. Lower angles give more privacy and less airflow, so pick the angle for what the louvres have to do.
How much should louvre blades overlap?
Enough that you cannot see straight through from the front. A blade that overlaps its neighbour in the front view blocks the straight-on sightline, and a gap opens it. CAD60 shows the largest overlap that will build for your blade and angle, and a readout says whether a viewer can see through, so you can trade privacy against airflow with numbers in front of you.
Should I set the blades out by overlap, pitch or count?
Use overlap or gap when privacy is the point. Use pitch when you are matching a supplier's blade spacing or the pitch is on the drawing. Use count when the job says exactly how many blades. Pitch and count both work out the overlap or gap for you and the notes state the result.
What is the difference between a flat, hollow, elliptical, aerofoil, Z and chevron blade?
A flat bar is the simplest and the cheapest. A hollow rectangular (RHS) blade is stiffer for its weight. Elliptical and aerofoil blades are extruded sections that look finer and shed rain well. Z and chevron blades are thin sheet sections; the Z has a lip at each edge and the chevron is a shallow inverted V, and both are chosen where the blade has to hide equipment from more angles than a straight blade would.
What does end-fixed in a channel mean?
Instead of welding each blade to the frame, a channel is fixed to each jamb and the blade end sits in it, held by self-tapping screws. CAD60 draws the channel, lists it in the cutting list, and cuts the blades shorter by what the channel takes. A carrier is the same idea with a punched channel the blades clip onto.
Do horizontal louvre blades suit a pool fence or a balustrade?
Check before you choose. Horizontal members can count as climbable, which matters for pool barriers (AS 1926.1) and for balustrades (the NCC). Vertical blades are the usual answer where that applies. This guide is not compliance advice: confirm the rules for your site with the certifier.