Replies

1. 
   MojoMan | Nov 28, 2004 12:47am | #1

   You might want to cut a 1x block large enough to support the base of the fixture and cut a 4" hole through the block and sheathing, cut out a rectangle of siding and mount the block on the sheathing with a little flashing over the block. This will provide a flat, weather-tight base for the light.

   Al Mollitor, Sharon MA

2. 
   pye | Nov 28, 2004 02:04am | #2

   They make a 3/0 box with ears that fits into a 3 5/8 hole, just drill a hole with a holesaw and screw through the ears. Some come with an adjustable bracket that pinches the box the box from behind, occasionally you have to trim the bracket with snips to accomodate your sheathing thickness. There is a baseplate for electricians that allows fixtures to mount true to lap siding. Watch that holesaw, you wouldn't be the first person to cut or nick the wire back there.

    

3. 
   davidmeiland | Nov 28, 2004 03:52am | #3

   I'll go with Al's recommendation for a 'light block', since your siding is probably lapped to look like bevel siding and will not provide a nice flat mounting spot for the fixture. Fixtures mounted directly on bevel siding will either sit on one piece and therefore be un-plumb, or bridge two pieces and look like hell. Cut a piece of 2x material that's a couple inches bigger than the fixture base in both directions. Cut thru the siding to mount that, but not the sheathing. Then drill the hole for the electrical box thru the 2x and screw it to the sheathing. If you can't find a shallow enough box to sit flush in 2x material, you'll have to drill the sheathing too, and then screw thru the side of the box into the 2x to mount the box... gotta drill your own mounting holes for that.

   If you really want to do a nice job, get a piece of z-bar flashing in behind the paper and out over the top of the block. Caulk the block in tightly on the sides.

4. 
   skyecore | Nov 28, 2004 07:37am | #4

   Many extirior lights have a sort of built in box, usually a round box that mounts directly to the outside, a hole in the middle where the wire comes out from the wall, and the top is open.. The topside of the box is the fixture ist self..

   -->

   measure once

   scribble several lines

   spend some time figuring out wich scribble

   cut the wrong line

   get mad

5. 
   DanH | Nov 28, 2004 03:56pm | #5

   My preference, if the base of the lamp is smaller than the exposure of the siding, is to cut a hole that will let the box be more or less flush. (Angle the box slightly to match the slope of the siding.) If you have a choice, try to get the top edge of the base about 1/2" from the bottom edge of the course above. (Be sure to remember that the base is a larger diameter than the box!!) This provides a drip edge that helps prevent water from running behind the fixture base.

   If you're really paranoid you can run a very small bead of caulk under the edge of the base, but it's not really necessary for a weather seal.

   Bend the fixture slightly to compensate for the slant of the siding.

   If the base of the lamp is larger than siding exposure, or you have metal/plastic siding, you need some sort of mounting block for the lamp.

6. 
   DanH | Nov 28, 2004 04:00pm | #6

   To mount the box itself, if you don't have access from the back, there are various types of "old work" boxes designed for this duty. Just pick one you like. In the worst case, if you couldn't figure out anything else, you could use a fan mount to anchor the box, but that would require compressing the insulation quite a bit.

7. 
   househelper | Nov 28, 2004 05:44pm | #7

   Electricians generally leave the wire behind the wall like this so the hole can be cut on the surface of the siding and not end up straddling two pieces of siding. You will have to cut the siding and the sheathing to retrieve the wire. That hole can be for a round old-work box (~3") or a rectangular old-work box placed on its side. Cut the hole so the base will sit flat against the siding. You may have to use a mounting block if the base of the fixture is larger than the exposed siding. Add silicone caulk around 2/3 of the base, leaving the bottom unsealed so any moisture can run out.

1. 
   Sphere | Nov 28, 2004 06:04pm | #8

   Depending on the fixture, a flat pancake box is all ya need. finding the wire is the hard part. 

   Spheramid Enterprises Architectural Woodworks

   Repairs, Remodeling, Restorations. 

    

    

1. 
   MarkH | Nov 28, 2004 06:55pm | #9

   Or you could do what was done to my house before I bought it. Stick wire through hole and connect it to light fixture. Screw light directly to siding. Hope for the best...

1. 
   Sphere | Nov 28, 2004 06:59pm | #10

   {G} seen it too.. 

   Spheramid Enterprises Architectural Woodworks

   Repairs, Remodeling, Restorations. 

    

    

2. 
   pye | Nov 28, 2004 08:36pm | #11

   Gotta use a pancake box at least,I'm wishing they come out with a "crepe" box for those ultra-thin applications.