What to Expect During a Custom Shower Installation in an Older Des Moines Home

Planning a Custom Shower in an Older Home? Look Behind the Walls First

Are you wondering what to expect during a custom shower installation in an older Des Moines home? If you live in one of the city's historic neighborhoods, you might be dreaming of a modern, spa-like bathroom retreat to escape the sweltering peak summer heat. Upgrading your daily routine sounds fantastic, but installing high-flow fixtures on aging infrastructure often leads to low water pressure and immediate drainage failure.

The reality is that a successful bathroom renovation is a plumbing operation first and a cosmetic project second. Homeowners must choose to properly retrofit hidden plumbing before laying a single piece of cosmetic tile, rather than cutting corners and hoping for the best. Attempting to connect a multi-head luxury shower to outdated pipes is a recipe for disaster. Before you start picking out glass enclosures and rainfall showerheads, you need a team experienced in professional plumbing services to evaluate your system. At True Comfort Heating, Cooling and Plumbing, our technicians ensure the bones of your house can support your vision.

Phase 1: Assessing and Replacing Galvanized Supply Lines

The first major hurdle in any historic bathroom remodel involves water delivery. Many pre-1970s homes with original galvanized plumbing still rely on the exact same supply lines installed decades ago. While these pipes were the standard of their time, they are notorious for failing from the inside out.

The problem with galvanized steel: Over decades of use, the internal zinc coating on galvanized pipes wears away. This allows rust, scale, and mineral deposits to accumulate inside the pipe. What was once a half-inch or three-quarter-inch pathway for water slowly chokes down to the size of a drinking straw. This severe restriction makes it physically impossible to power modern, multi-head custom shower systems.

This is a ubiquitous issue in older Des Moines housing stock. In our experience working in these historic homes, we know a realistic assessment of the original plumbing is non-negotiable. Walls will need to be opened up to access these vertical runs. Skipping this step guarantees a disappointing, low-pressure shower experience and heavily increases the risk of a pipe bursting behind your brand-new tile.

Comparing Supply Line Materials

Pipe Material	Typical Lifespan	Impact on Custom Showers
Original Galvanized Steel	40 to 50 years (likely expired)	Severe mineral buildup restricts flow; cannot support multi-head systems.
Modern Copper	50+ years	Excellent flow rate and durability; highly resistant to internal scaling.
PEX (Cross-linked Polyethylene)	40 to 50 years	Flexible, scale-resistant, and ideal for retrofitting through existing wall cavities.

Phase 2: Upsizing Aging Cast Iron Drains for High-Flow Fixtures

The Problem: A standard, older showerhead typically outputs around 2.5 gallons of water per minute. A modern custom shower system—featuring a rainfall head, standard head, and multiple body sprays—can easily output double or triple that volume. Older homes were never designed to drain water at that velocity.

The Cause: The original plumbing in mid-century homes typically features 1.5-inch cast iron drains. Just like galvanized supply lines, cast iron drains suffer from decades of internal corrosion and buildup, further reducing their already limited capacity. When you blast 7 gallons of water per minute into a 1.5-inch cast iron drain, the water has nowhere to go. It will quickly pool at your feet and overflow the shower pan, leading to severe water damage.

The Solution: To handle the increased water volume safely, the drainage system must be upsized. This involves cutting out the old cast iron trap and branch line, then installing a modern 2-inch PVC or ABS drain. This upgrade is not just functional; it is strictly required to meet current Iowa plumbing building codes for high-flow fixtures. Our plumbing team always assesses proper venting to ensure the new drain flows freely without gurgling or siphoning the trap.

Phase 3: Evaluating Your Hot Water Capacity

A beautiful new shower is useless if the water turns ice-cold after three minutes. There is a direct correlation between high-flow custom showerheads and rapid hot water depletion. Standard-capacity tanks in older homes are rarely sized for luxury shower systems.

A custom shower project is the ideal time to evaluate your current hot water system's age, recovery rate, and total capacity. Upgrading the water heating system is frequently a necessary parallel project to ensure the new shower can actually be enjoyed. Here is how our professionals evaluate your home's readiness:

1. Calculate the new demand: Our technicians will add up the total gallons per minute (GPM) of all showerheads and body sprays that can run simultaneously in your new design.
2. Assess current tank capacity: A standard 40-gallon gas or electric water heater will be drained incredibly fast by a 6 GPM custom shower system, leaving you with barely six or seven minutes of hot water.
3. Review the recovery rate: The recovery rate measures how fast the unit can heat new water. Older, inefficient tanks cannot keep up with the continuous draw of a multi-head shower.
4. Determine the upgrade path: Depending on the calculations, we may recommend a larger 50-gallon or 75-gallon tank, or transitioning to a high-capacity tankless system for endless hot water.

If your system falls short, upgrading your water heater ensures your luxury investment performs exactly as intended.

Phase 4: Waterproofing, Fixture Installation, and Project Financing

Once the rough-in plumbing is complete—meaning the new supply lines are run, the 2-inch drain is set, and the water heater is upgraded—the project transitions to the structural and cosmetic phases. This is where the unseen preparation pays off.

Before any tile is laid, the shower enclosure must be meticulously waterproofed. This involves installing specialized cement board or foam backer boards, followed by a continuous waterproofing membrane. This membrane ties directly into the new drain flange, creating a watertight envelope. Meticulous behind-the-wall preparation ensures the longevity of your expensive tile and fixtures, preventing mold growth and structural rot in the surrounding framing.

Proper infrastructure upgrades add significantly to the project scope. Replacing vertical pipe runs and upsizing drains requires time, specialized labor, and materials. Because these are necessary steps rather than optional upgrades, financial planning is an important part of the process. At True Comfort Heating, Cooling and Plumbing, we provide transparent estimates and flexible financing options to help manage the scope of invasive retrofits, allowing you to do the job right the first time.

The Importance of Discipline in Invasive Plumbing Retrofits

Retrofitting a custom shower into an older home is a highly invasive process that requires extreme attention to detail. Working inside the walls of historic Des Moines neighborhoods like Beaverdale or Waterbury means navigating decades of previous repairs, settling framing, and delicate lath and plaster.

Cutting corners on unseen infrastructure leads to devastating water damage down the road. If a contractor offers to simply connect new luxury fixtures to old galvanized pipes to save time, you will inevitably pay for that shortcut through poor performance and future leaks. The walls will eventually have to be torn open again to fix the root problem.

This is why working with our veteran-owned and family-operated company matters. We bring a military-like precision and discipline to complex behind-the-wall plumbing projects to ensure that nothing is overlooked. A methodical, step-by-step approach protects the historical integrity of your home while delivering the modern luxury and reliability you expect from a new bathroom.

Frequently Asked Questions About Custom Shower Installations

What hidden plumbing issues are common when installing a shower in an older home?

The most common hidden issues we encounter revolve around outdated materials that have reached the end of their lifespan. Our team frequently finds mineral-choked galvanized pipes that severely limit water pressure. Additionally, undersized 1.5-inch cast iron drains that cannot handle high flow rates are standard in older homes. Finally, we often discover rotted framing or non-existent waterproofing behind old tub enclosures once the walls are opened.

Do you need a permit to replace a shower in Iowa?

Yes, significant plumbing alterations generally require a permit. While swapping a showerhead might not, moving drains, replacing supply lines, or upsizing a drain to 2 inches absolutely falls under code enforcement. Code compliance ensures safety, proper venting, and correct drainage. Always verify current regulations with local authorities or a licensed professional before beginning demolition.

Does a custom shower require a new water heater?

Not always, but frequently yes. Multiple showerheads and body sprays deplete standard 40-gallon or 50-gallon tanks incredibly rapidly. If your new shower outputs 6 gallons per minute, a standard tank will run out of hot water in minutes. A thorough evaluation of your current capacity and recovery rate is necessary before finalizing your showerhead selection.

Can you put a high-flow shower in an old house?

Yes, but it requires upgrading the supply lines for adequate pressure and the drain lines for safe capacity. It cannot simply be connected to original 1950s or 1960s plumbing. The infrastructure must be modernized from the basement up to the bathroom to support the increased water volume without leaking or overflowing.

How long does a custom shower plumbing retrofit typically take?

The infrastructure phase adds several days to a standard bathroom remodel. Tasks like rough-in plumbing, galvanized pipe replacement, and drain upsizing must be completed before any drywall or cement board goes up. The exact timeline depends heavily on the condition of the original pipes and how accessible they are from the floor below.

Ready to Upgrade Your Home's Plumbing Infrastructure?

A successful custom shower starts with robust, modern plumbing infrastructure, not just beautiful tile. Replacing restricted galvanized pipes and updating undersized drains prevents unpleasant surprises, ensuring your new bathroom functions just as well as it looks. If you are planning a renovation, schedule a professional inspection with our team at True Comfort Heating, Cooling and Plumbing to evaluate your home's readiness. Getting a clear, realistic explanation of the necessary upgrades will protect your investment and guarantee you get the spa-like experience you deserve.