ICE is correct in everything he is saying. Allow me to illustrate the simple legwork to show how you find out what the current codes of Rowlett are (and what you have to build to for any new construction). Even if you have only ripped out an old shower and are installing a replacement shower, this work is new construction. Mostly (I'll explain later),
it doesn't matter what was there in the past. If the contractor is legitimate and will be obtaining a city permit for the work to be performed, he is bound the conditions of the permit to do the work in accordance with the current city codes.
The internet is a huge tool these days. Start by visiting the City of Rowlett, TX website. Using the search tool on the City's website, look for "adopted building codes". In the results, click the first entry which takes you to:
https://www.ci.rowlett.tx.us/882/Adopted-Codes
Behold! Building Codes is the first in the list. Assuming this discussion is about a single family home, the adopted code is the
2012 International Residential Code . You will notice that there is a link to local amendments to the code. Click on the link to display (and print out if you wish) the amendments...they might alter sections of the code you will be looking at.
The I-Codes (editions 2009 through 2018) can be viewed
free of charge on ICC's website (
www.iccsafe.org). Simply go to the Public Access tab in the upper right corner of the webpage and follow through from there. There is no excuse for anybody (including the contractor) to say they don't know what the code is.
The applicable section is Shower Receptors, Section P2709. (Note that the City's amendments does not alter Section P2709). Specific to the installation of liners, Seciton P2709.3 applies.
The liner must be sloped 1/4 inch vertical per horizontal foot. There are numerous other shower receptor construction details and requirements within Section P2709. Also, note other shower compartment requirements in Section P2708.
LINER LEAK TESTING REQUIRED: See Section P2503.6.
Now, I'll explain my comment: "
Mostly,
it doesn't matter what was there in the past." A simple example is where an existing shower doesn't comply with the minimum dimensional requirements in Section P2708 and there isn't any other structural re-configuration happening in conjunction with the shower reconstruction
and it isn't easily possible to make the shower dimensions comply. In other words, provided that the new shower will not be any smaller than what is it was before the new work, a code official usually understands that issue doesn't cause the work to expand in scope. However, this doesn't mean that a non-compliant shower (under the codes that were in effect in 1992, the year of original construction) will be acceptable to the code official. This is why the local code official is involved.... to make such judgement calls in light of special circumstances he sees for the project.
BUT, 1992 construction is recent enough that an original shower that was built-to-code then, should have dimensions that will comply with the 2012 IRC. Measure the existing compartment to determine if you will have an issue.
There are may other details addressed by the 2012 IRC such as shower controls, wall construction, etc. Review the current code to determine the requirements.