Subscribe or Renew Membership Subscribe Renew

Cutting Holes In Sloped Wood Cielings For Sloped Can Lights

anthonygualtieri's picture

I am presently planning for a cathedral wood ceiling for a roof that is 10 on 12.  There are light  cans whose  housings are vertical, (the light beam projects straight down) rather than on the plane of the ceiling surface.  As a result a simple round hole would not do the job.    Oviously I have to cut oval holes to accomadate for these lights.  Does anyone know how this is done? 

Yes (post #207323, reply #1 of 7)

There should be a template included (though now that I think of it...............since those cans are semi adjustible and the last ones I did were in drywall..............might not be a fixed template in the box).

Get a pc of floor paper (or go to the meat counter and get some of that paper)

layout the slope of ceiling On that paper)- fold that layout line up (L-shaped paper now).

Set the can back down on it, trace the arcs on the L'd paper you just bent up.





become a math wizard and layout that oval using numbers and drawn arcs........................


By the way-you have something up there as an air block already right?  You don't just nail on tongue and groove wood and hope for the best.  You'll leak air up into the rafter cavities and end up with lost heat and ice damming or worse yet-water stains on your ceiling from the condensation.


so back to the oval-the can is installed and you need to cut the drywall-well, take that paper you got from the butcher and staple it up between the rafters-over the can, and trace it.  Cut out the tracing in the right spot on your pc of drywall-pencil that line.

Keep the template you made and transfer it to your boards.  Ideally, lay enough boards side by side fitted together properly and make the one oval tracing on all the boards at once.  Separate, cut out and install.


or use math................

A Great Place for Information, Comraderie, and a Sucker Punch.

Remodeling Contractor just outside the Glass City.


Cutting Holes In Sloped Ceilings For Sloped Can Lights (post #207323, reply #2 of 7)

Thanks Calvin.  I do have templates for the lights.  The issue is the angle of the cut.  If I make it 90 degrees to the face of the wood the hole will need to be quite large.  I was hoping there was  some way of making the cut so it was vertical to the floor not the board face.  And yes on the air block.  Since I am running the boards vertical, I plan on 5/8's plywood for the whole ceiling, taped at the joints.

Anthony (post #207323, reply #3 of 7)

Take a look at this install sheet from Juno:


The can shown is a "super slope" can housing-meant for maybe 7/12-12/12.

I think but can't say for sure as it's been awhile.....................

You tip the socket holder and secure with screws-this points it straight down.


What the heck am I writing this for................I think you mean the cutout in the board needing to be perpendicular to the floor (an angle cut that changes as you go around?)  I don't think so-the last ones I did were smaller cans (the socket, dome and trim all hooked together b/4 you installed it in the can housing.

(But, when stacking drywall (or ply in your case) with 3/4" of board over do need to make those cuts on a bit of bevel  (at least the uphill part of the oval) so it doesn't interfere with the dome/trim.)   **That is, if you can't lower the can sleeve down for a thicker ceiling finish**


Most cans however, extend down via an adjustment screw/screws,  allowing the bottom edge of the "can" to slide down to the finished surface.  Don't know what the adjustment dimension is b/4 you have to hang the can lower below the joists.........

In most installs I've done, I don't remember a problem once you cut to the oval with the can bottom edge adjusted for finished thickness.  Whether it can go from 1/2" to 1-1/4 or so, I cannot say.  Do you have the dam thing there in front of you?  And it is a steep slope can housing?  How much will it adjust down?

A Great Place for Information, Comraderie, and a Sucker Punch.

Remodeling Contractor just outside the Glass City.


Anthony (post #207323, reply #4 of 7)

Here's a link to the Juno LED can for steep slope-   SPECs

The adjustment for the ceiling thickness goes to 1" without horsing around with dropping the housing below the joists (which will interfere with your 5/8's sheeting).

So-5/8's sheeting plus 3/4 (?) finish board ceiling-1-3/8"  ceiling thickness.


Do some testing, but you should be able to "hog out" that angle on the high side with even a coping saw, no?  Just cut the face of the arc to the board face, hog out the remainder behind.

A Great Place for Information, Comraderie, and a Sucker Punch.

Remodeling Contractor just outside the Glass City.


Obviously, use an oval hole (post #207323, reply #5 of 7)

Obviously, use an oval hole saw.

Or, cut the hole with your jigsaw or whatever square to the wood and then find a router bit with the right angle to knock back the top side of the cut.

Or, just make the hole a little larger --- the trim ring should cover the gap.

Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville

Cutting Holes In Sloped Ceilings For Sloped Can Lights (post #207323, reply #6 of 7)

Thanks to all for the suggestions.  I do not how it will work but I am going to try an extra deep hole saw with a longer centering bit. I am going to rig a level on the top of the drill set for the angle needed for a 10 on 12 roof.  The board I am drilling will be on a level surface.  IF this works the oval will be formed by the angle of the hole saw???????

ceiling lights (post #207323, reply #7 of 7)

are these surface mounted cans? If they are not finished on the outside a housing of some sort would have to be build around the housings. Personally I do not want any cans installed in a cathedral ceiling (reduced insulation, some vaporbarrier difficulties)