Converting a bathtub to a shower with a 1 1/4 inch drain
Older homes often feature 1 1/4-inch drain lines, but modern building codes require a 2-inch pipe for a new shower installation. Upgrading this line requires breaking into old cast iron plumbing, which stops homeowners from finishing their bathroom renovations without major structural work.
Core Friction Pattern
Analysis of 2 peer accounts across online developer and community forums reveals that “Converting a bathtub to a shower with a 1 1/4 inch drain” repeatedly surfaces due to edge-case mismatches between standard defaults and real-world environments. Standard troubleshooting frequently falls short, compelling practitioners to develop custom workarounds.
+1 alternative community-tested workaround cataloged below.
What people tried
Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.
Found another way around this?
Share your steps and trade-offs so fellow engineers don't have to reinvent the wheel. No account required.
Converting a bathtub to a shower with a 1 1/4 inch drain
- 1Cutting into the concrete to expose the main sewer line fitting, replacing old cast iron with PVC, and using specialized adapters like Fernco couplings.Did this help you?
- 2Reading subreddit information and posting photos of the completed work for community reviewDid this help you?
In their words
Unedited, grouped by where they were said, most upvoted first within each place, each linked to the thread it came from.
“Updating the bathroom drains in our newly purchased home.”source ↗
“Trying to get things up to code.”source ↗
“Any changes needed for when I get ready to put in the next one one? Any major concerns with the one I put in?”source ↗
“I am renovating my bathroom in my early 70’s house and am converting from a bathtub to a shower. Issue is the drain line is 1 1/4” and code says 2”.”source ↗
Where this came up
People with this problem also raised
- 4How to fix a sink drain pipe that is too short
- 3How to tie in a vent line and shower drain in tight spaces
- 53How to fix a leaky plumbing valve that doesn't fit a new faucet
- 4How to fix a sink drain without removing the P-trap
- 7Kitchen tap internal pipe disconnected with no slack
- 5Why does the drain snake keep coming out the other drain?