Window Shutter Dimensions and Angles
Thoughts on the the spacing and angling of louvers in traditional window shutters. June 4, 2012
Question
I’m building some shutters 1 5/8 inches thick. I just cut a prototype on the CNC and the slats don’t look right at 45 degree. Is there somebody that as built them with other degrees? How close are the slats? My slats are 3/8 thick and 1/2 apart.
Forum Responses
(Architectural Woodworking Forum)
From contributor O:
Louver size, spacing, and angle are all variable depending upon the application. Belvedere and cupola louvers are large and have a strong angle - 20 degrees off vertical. Exterior window shutters have less of an angle and the slats will average about 1/4" and 3/8" apart. Lap is also a factor for privacy. Look at some historic samples in your application and model after them.
From contributor U:
In addition to what Contributor O is saying we find that most fixed louver shutters that we build have a 3/8" spacing between louvers. One reason we stay with that is we like using a consistent space when laying out panels when there are so many other factors that may change, plus our equipment is set for that space and it is difficult for us to change over. The louver thickness, louver width, and most of all the stile thickness determines the angle at which we set the louver. 20 degrees is pretty common for our average job using either a 1 3/8" or 1 1/2" stile in combination with a 3/8" x 2" louver.
I have done fixed slats up to 3", but we used a thicker stile and tilted the louver angle to get the desired result. We usually shoot for an overlap of 1/4" so that you cannot actually see through the louvers. So while we commonly use 20 degrees, we do what it takes, but we try to make sure first that it is still pleasing to the eye.
From contributor O:
Contributor U said what I left out - the width of the slat will determine the angle as a factor of stile thickness. When I learned shutter making in the mid 70's, the shop I worked in did historic repro and Early American stuff and so louvers were narrow slats - about 1-1/8" to 1-5/8". Current trends have wide slats at a more vertical angle. You probably have already found there are no standards to look up.
From contributor U:
That's interesting. The historic work is where I learned the fixed louver end of this business too, mostly Florida and Georgia. Over the years I was always impressed when people brought in items like operable louver exterior shutters made in 1830 that were still functioning. It seems like too many makers of current products have abandoned tried and true techniques that really work. You’re right, there are few standards that apply to this work.
