What size hole in subfloor for offset flange?

[Killacam311]

This is probably a very easy question but I just put down new subfloor and I don't want to screw anything up at this point.

I had to replace a rotten beam and new subfloor. I know an offset flange fits my current toilet so long as it is drilled as close to the beam as possible, because that is what was there before.

I can't find the answer to this question anywhere - was size diameter hole should I put in my new subfloor to fit this Oatey offset flange? PIctures included. I added a measurement of the flange, which is around 6 inches. I drill a 4 inch hole, which is my largest hole saw, but it doesn't fit.

I know I am overthinking this but I don't have anybody in my life to ask so if youtube doesn't have an example I rely on this community to give me piece of mind. Much appreciated. I want to draw a nice black circle on the subfloor and hit it once with the jigsaw.

 

[Jeff H Young]

tell you the truth I eyeball it draw it out on plywood cut hole , check cut a bit more trial and error not too tight and not too loose a fit

 

[Sponsor]

 

[WorthFlorida]

How much room, width wise, do you have? You need 15" centered on each side of the flange to the drywall or cabinets for 30". Going left looks like you might cut into the joist, can you go right? To make the hole larger, a jig saw is needed to make the hole oblong. You might be able to just cut out the 3/4" subfloor and the flange may fit over the joist.

 

[Reach4]

screw hole centers" 6.125 inches. OD 7 inches.

I think circle smaller than 6 inches would be better, then rasp/cut out clearance at the outlet place. Note the ring can be rotate on the plastic to put the mounting holes where you like.

I think you will be making a custom cutout, maybe starting with the 4 inch hole, but a 5 inch hole starting point should mean less rasping or jigsawing. I was unable to find a prescribed pattern.

Expec

 

[wwhitney]

Make some trial cutouts on scrap the same thickness as the subfloor. When you get a nice fit, confirm that the part that sticks below your subfloor won't hit the joist. Then use your template to mark the subfloor and cut it out.

Cheers, Wayne

 

[Killacam311]

Thanks all for the great advice. I am going to make a mock up in the garage and do some experiments. I appreciate the advice

 

[Jadziedzic]

Grab a piece of foam core board from an art/hobby supply store and use that for your prototype cut-out; a lot easier than carving wood, and you can use the pattern to cut out the real subfloor.

 

[Jeff H Young]

How about turn ring upside down set it where you want it trace around outside the ring , then make little dots with the pencil to the inside of that big circle 1 inch, 1.060 1.25 1.375 " What ever amount you determine necessary connect the dots .
and then cut away should be pretty easy. I always put solid blocking to screw ring to rather than just rely on small screws in subfloor

 

[iconoclast hero]

@OP: What was the answer?

 

[iconoclast hero]

How about turn ring upside down set it where you want it trace around outside the ring , then make little dots with the pencil to the inside of that big circle 1 inch, 1.060 1.25 1.375 " What ever amount you determine necessary connect the dots .
and then cut away should be pretty easy. I always put solid blocking to screw ring to rather than just rely on small screws in subfloor

I don't think that's going to work terribly well, especially since as has been pointed out the flange cutout is not a circle but rather an oblong cutout (i.e., not an oval) that is not symmetric along one of the two axises. I'll put some pictures up if the moderators OK this message, but here's what I did:

I called Oatey and complained that they didn't have a template or any instructions (because there's ca 8 billion people on this planet and I'm not the first one who's had to reinvent this particular wheel!). I was told to use a hole saw a little under 5" to which I responded none of my hole saws are denominated in "a little less than x." I made a template from some acoustical tile that had been laying around, giving me roughly the thickness of the subfloor but something much easier to rasp away. That let me create a paper template I could use on the floor.

I notched my joist.

I spent a good deal of time with the flange screwed to a piece of plywood with a cutout that was too big for the flange screws to hit, but it allowed for me to mark lines where the flange needed to be once I put the subflood back down.

I turned the flange upside down, put my paper template on it, marked two diagonal corners of the paper, put the paper back, and then marked the floor for the flange opening. (I crosshatched across the cutout rather than try to trace or anything else, then drew a circle around where the crosshatches stopped.)

From there, I used a 4.5" hole saw at somewhere close to the center (but inside the template marks) to remove the bulk of the material. I grabbed a router and some Warrior rotozip spiral cutoff bits and just removed the rest of the material to get to the template marks. This was probably enough (the flange is tight in the opening which is great), but I need to do a few mm worth of tuning to get everything lined up with the joist.

Then I realized that I would have been better off with a 10" rough in (going that way now anyway — but I could have avoided notching the joist) or a wall toilet, but those exit the back and might require boxing out the joist behind after all... That would've been fine with the planned 2x6 wall behind, but now I have a flange in the floor so...

Anyway, I'm considering framing in a hollow 2x6 wall up behind it (think opening for a pocket door, but with plumbing vent and insulation).