What box is best for Outside Wall Light Fixture in Existing T-111 to cut in?

I am wondering just what box would be the best for adding a couple of Lights to an outside of an Out Building. When I have gone to Home Depot Type Stores they have a couple of round cut in type boxes but they vary as to the diameter. And not having the fixtures yet I am wondering will most light fixtures cover these being some boxes are 3/8 larger that others. They will be cut into T-111 wood.

Why does these boxes vary in size and diameter? Or is it okay to use a standard duplex box (not round) for this application? Would like the light fixture to mount flat to the wall to be able to run a bead of silcone around it to keep any water out. Some of the boexs seem to bevel up and out and would keep some fixtures from being flat up against the wall.

Any information would be help just in te planning stages.

Thanks,
LFM

Most of the fixtures have a large enough base to cover any standard single round or rectangular box. They usually have a cup that allows some room behind them that covers the box, but not always.

It seems that some boxes bevel out and when you mount the fixture to the box it is about 1/8 to 3/16 out and away from the wall and looks bad. While others look okay and most of the boxes I have seen some son't have the screw holes lined up to the fixture just right either. I know each fixture maker has their idea of what box works but most don't have any information on the outside of the box to tell you what it fits on. And some stores won't allow you to open a box to take a loook at just what it fits on either.Guess I will go with a cut in box round that has a metal bracket on the backside that secures in the wall and hope it works just need to get a wolesaw that big to het it set in the T-111 but that should not be an issue.

Thanks for the information.

LFM

The fixture should have a "rotating/adjustable" mounting bar if it uses screws to anchor to the box. If it uses a single filial on a screwed stud, then the mounting bar can be installed at whatever angle the box requires.

Thanks for help...

LFM

Try something by Arlington....


http://www.arlcatalog.com/Siding/siding.pdf

Most of the stuff is for Vinyl but some of the flat mount types are listed for T-111.