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New toilet flange to sewer stack adapter?

Our house was built in 1946 and I'm replacing the floor in the tiny upstairs bathroom which just includes a small sink and toilet.

I took up the plywood underlayment down to the subfloor. The toilet was attached the floor by screws and instead of a wax ring that sealed the connection between toilet and sewer stack I found a foam ring. There was no flange as you would normally see in today's construction.

The pipe coming up from the floor is made of a very malleable metal. Not sure what.

I'm wondering if I can install the underlayment like it was before and install a new toilet flange over the sewer stack pipe opening (similar to replacing broken flange) OR do I need some special adapter? Basically the flange would bolt to the new floor as you'd expect, then I would install the toilet with a new wax ring to seal the connection between the stack pipe and the toilet.

What do you guys think? Is that a pro way of finishing the job or do I need a special part. Please see images for illustration.

Thanks for your help.

Re: New toilet flange to sewer stack adapter?

That is a lead bend. What they used back in the day. You probably have a Cast Iron stack in the wall directly behind toilet. You can put an expandable flange inside of that

Re: New toilet flange to sewer stack adapter?

Yep, there's a cast iron stack behind the wall and the lead appears to be in fine shape.

MSSP: Can you post a link to the produce you're recommending?

Re: New toilet flange to sewer stack adapter?

You really don't need to change anything about what you already have. The lead "closet bend" as they were called, is meant to have its upper end flanged over to accept a wax ring just like you see has been done.

There's no sign of damage from leaking water on the surrounding wood floor, so you know that the old setup worked.

Go ahead and fit in a two-pc plywood filler around and under the existing lead flange. Then, using a hammer, gently tap the lead flange back down onto the filler to re-form the flange.

When you set the toilet, you'll use a wax ring for the seal, and the toilet is held down by the use of hanger bolts, which are just double-ended screws: one end has threads for wood, which you screw into the wood beside the lead flange, positioned to align with the holes thru the toilet bowl; the other end of the hanger bolt has machine threads for accepting a nut after the bowl is set in place, and, which nut is what tightens the bowl down. Buy brass hanger bolts, or at least brass coated ones.

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