Converting a tub to a shower in a condo

In many condos you can replace a tub with a shower, but it is rarely a simple swap. Whether it works, and what kind of shower you end up with, depends on your HOA's approval, where the drain can sit in a concrete or framed floor, how the new shower is waterproofed over the unit below, and how much depth the floor has for a sloped pan. Check your CC&Rs and talk to building management before you design anything.

The good news is that most condo tub alcoves already have the right footprint for a shower. The typical five-foot alcove becomes a comfortable shower with a bench or niche. The work is in what sits under and behind that alcove. If you want to understand what a tub-to-shower conversion involves in general, start there; this article covers the condo-specific questions.

Start with the HOA, not the showroom

Condo associations usually treat anything that touches plumbing, waterproofing or the floor structure as an alteration that needs written approval. Many buildings have an architectural or alterations application, and some want drawings, a contractor's certificate of insurance, product data for the waterproofing membrane and sound underlayment, and a schedule. Common rules cover work hours, elevator reservations, where debris can go and whether water to the stack can be shut off, and for how long.

Ask management for the alteration package before you commit to a layout. It is much easier to design within the building's rules than to redesign after a denial. Our guide to condo HOA rules goes through the approval process in more detail.

The drain: what the floor allows

A tub drain sits at one end, usually close to the wall, and connects to a trap below the floor. A shower drain needs to sit somewhere the floor can slope toward, and a center drain or a linear drain at the back wall each puts the drain in a different spot. Moving it any distance means working in whatever is below the tub.

Concrete slab buildings

In mid-rise and high-rise concrete buildings, the tub often sits over a slab with a recess or a blockout for the trap. Moving the drain means cutting or coring concrete, and that may not be allowed. Many newer concrete buildings use post-tensioned slabs, where steel tendons run through the concrete under tension. Cutting one is a serious structural problem. Buildings like this often require the slab to be scanned before any cutting, and some require an engineer's sign-off or prohibit coring altogether. The practical result is that many concrete-building conversions keep the drain close to where the tub drain was.

Wood-framed buildings

Many older low-rise condos in Los Angeles are wood-framed, with joists under the bathroom floor. Relocating a drain here can be more flexible, but the pipe runs into the ceiling of the unit below. Access usually means opening that neighbor's ceiling, which requires their consent and the HOA's, and a plan for patching and painting it.

Waterproofing over someone else's home

A tub is a sealed vessel. A tiled shower relies on a waterproofing membrane under the tile to keep water out of the structure. In a condo, a failure does not just damage your subfloor; it shows up as a stain on your neighbor's ceiling. Associations know this, which is why many ask for the membrane specification and some want a flood test, where the finished pan is plugged and filled with water for a period before tile goes on. Even where it is not required, it is a sensible step.

Curb, low curb or curbless

A shower floor has to slope to the drain, and the slope needs height. A curbless shower requires recessing the floor so the pan starts lower than the bathroom floor. In a concrete building that usually means the slab would need to be lowered, which is often not allowed. In a framed building it can mean cutting down or sistering joists, which needs structural review.

So most condo conversions end up with one of two options:

• A standard curb, similar in height to a tub's side wall but much easier to step over. This gives the pan the most depth and is the simplest to waterproof.
• A low curb, where the floor is built up slightly and the curb is kept short. This works when there is enough room between the slab or subfloor and the finished floor to slope the pan.

If a true zero-threshold entry matters to you, ask early whether the building will allow the floor work it needs. Some units can manage it; many cannot.

Sound

Removing a cast-iron or steel tub and replacing it with a tiled shower changes how sound travels. Many buildings require acoustic underlayment under hard floors, and some apply the same rule to the shower area or the bathroom as a whole. Water hitting a tiled floor is also louder below than water landing in a tub. Plan the underlayment and membrane system together so the waterproofing is not compromised by the sound layer.

Should the unit keep a tub?

This is a resale question more than a construction one. In a two-bathroom unit, converting one tub and keeping the other covers both kinds of buyers. In a one-bathroom unit, removing the only tub may matter to families with young children, and to some buyers it will be a negative. For others, especially in buildings with older owners, a walk-in shower is exactly what they want. There is no universal answer, but think about who is likely to buy a unit like yours before deciding. If you are weighing the whole room rather than just the tub, our condo remodeling page covers the broader scope.

Logistics that shape the schedule

• Getting the old tub out. A cast-iron tub may need to be broken up in place, which is loud and needs to happen within allowed hours.
• Water shutoffs. Some buildings require notice before the riser is shut off, and some only allow it at set times.
• Elevator reservations and protection for common areas on delivery and debris days.
• Parking and staging. Many buildings have limited space for trades, which affects how materials arrive.
• Glass templating after tile, and an access route for the panels through halls and the elevator cab.

Before you ask for bids, gather the HOA's alteration rules, any drawings of the unit, and a few photos of the ceiling below if you can get them. With those, a contractor can tell you quickly whether the conversion you want is realistic in your building.