I'm helping out a family member who needs a new toilet (cracked tank). And before installing a new toilet I was humoring the idea of getting rid if the weird rider it's on. I've seen this in older homes, but never really knew why they did it. There's an obvious vent involved here, but is there anything that should stop me from removing the riser, shorting the vent to the floor and shortening the toilet drain down to the floor as well?

I know there's some restrictions with length/angle on the toilet drain, but should I stay away from this idea? Any thoughts and info from the many wise folks here who are way smarter than me? Thanks! Much appreciated.

I attached a pic as well...

 

We can't possibly know what's under there or why they did it that way.

 

Fair enough. I was assuming there might be a common reason for doing so as I've seen other old homes with similar scenarios. I'll open it up and get a picture underneath. Again, I appreciate the help!

 

Maybe to get a forced air register in that room. See if there is an actual duct behind that grill.

I've seen those platforms built in basements in old homes to get the toilet above the sewer line.

 

I had my sister take off that front board, sure enough, NO duct. Just a grill to an open space, then another board (similar to front board in picture) blocking view right where the toilet is. She's unsure how to remove it, so I'll be over to check it out in the next day or so. But, for now, I can confirm, there's no actual air duct and it appears that the toilet drain is just going straight down trough floor.

I should also mention that is bathroom is on the second floor.

 

That riser is definetely and after thought and someone had a reason for building it in the first place. It could have been done because of some plumbing issue. It also could be that the toilet leaked and the floor & framing underneath rotted out. Instead of fixing the structural issue they just built a platform over it. If you decide to get rid of the riser I can almost guarantee that you will have to fix whatever problem caused them to build the platform... so be ready for a can of worms.

 

Can you get or rent a fiberoptic camera or plumbing snake camera and drill a small hole on the side near the toilet and get a look inside?

(You may need two or three holes 16 inches apart to correspond with "joist" spacing within the riser but start with just one hole to get an idea of "joist" orientation first.)

 

Update:

I had a chance to check it out better, while doing minimal damage to the riser. I was able to remove a board covering the drain. Turns out what looks to be that the drain is coming in on the side of the wall as opposed to the ground. Hence, they added an arm sending it up and then building the riser to be at an appropriate height for the toilet.

So...correct me if I'm wrong here, but does that look like the gist of it? And if so, is there anything stopping me from taking out the toilet/riser and getting back to the flange (assuming the flange is in okay condition? And that it is at a correct height?) and then installing one of those back outlet toilets instead? On the floor, no riser. I've been meaning to install new flooring anyway.

Am I missing anything here? Again. thanks so much for the info!

 

I check the price and availability on a new toilet before tearing out the old one. Lead times can be crazy these days.

 

Back-flow toilets also mount to the wall, and often require a 2x6 wall to support it.

But in general, your idea is a fine one. The last owners probably didn't want to spend the extra money on a back-flow toilet and came up with this solution instead.

 

I have finally had a chance to get going on the riser toilet project. I removed the riser (someone really overdid it on the nails for some unknown reason, a nail almost every 6"), was a beast. One nice surprise was that I uncovered an existing water inlet with shut off valve. I was planning on opening up the wall and adding an inlet from the sink area, as the original, riser created just ran an exposed hose from the sink water supply. So that was nice, and it works.

I was planning on tiling the floor anyway, so removing the riser and exposing the lack of linoleum isn't a big deal.

My question:

The wall drain is roughly 4.5" off the ground, looks to be the same height as the actual back outlet on the toilet. When I put in the tile, I don't really expect it to perfectly line up. And I imagine that isn't normally the case. So I assume (dangerous, I know) that there are flex, neoprene fittings that connect rear outlet toilets to the wall drain that can compensate a little height difference from toilet outlet flange to the wall drain, is that right? If so, anything to look for? I read somewhere that wax ring flanges are not recommended for rear outlet toilets, so neoprene would be best, that true?

Again, thanks for all the help!

 

Don't count on finding a fitting to compensate for a height problem. The ones I've seen (very few) have no room for vertical adjustment.

 

I've never heard of a rear-outlet toilet that is adjustable more than maybe 1/2". Here's an installation manual for a random American Standard I found. It calls for a 4" on center drain. I'd imagine you could go to about 4.5" above the finished floor, but I would measure or call the company to be sure.

https://images.homedepot-static.com/...f5992a8228.pdf

 

Thanks guys! I appreciate the info. I've decided to remove the floor and build it with some 1/2' (might go with 5/8" if that's the minimum requirement for the tile, still need to check) plywood over the original plank diagonal board flooring. That along with the 5/16" tile and 1/8' ditra, it should put me within 1/16" or so, away from a 4" center line on the drain to the toilet. At least...according to all of what I measured. So you think it's okay to be maybe an 1/8" give or take off with the flange to toilet height? I haven't ever installed a rear drain toilet before.

And to think...this all started with a cracked toilet bowl fix!

 

Keep in mind that most sheet materials (plywood, osb...) are not 1/2" or 5/8". They are some other thickness like 7/16" or 19/32". If you need more height you can shim between your subfloor and new sheeting with a non compressible material. I use tar paper when I need just a bit more height.

 

You could also shim the toilet 1/16 to 1/8 inch above the floor since it is back outlet and would not affect sealing as it might for the wax ring to a standard floor outlet