- Pre-slope
- A mortar bed installed beneath a shower pan liner, sloped toward the drain before the waterproofing layer goes in.Why it matters: Water that gets through grout travels along the waterproofing layer, not the tile. Without a pre-slope, that water sits on a flat liner instead of draining, and the shower smells long before it leaks.
- Thinset
- The cement-based mortar that bonds tile to the substrate. Modified thinset contains polymers that improve adhesion and flexibility.Why it matters: Large-format tile requires a mortar rated for it and a notch size to match. Using standard thinset under a 24×48 tile is one of the most common causes of hollow spots and later cracking.
- Bonded waterproofing membrane
- A continuous liquid-applied or sheet membrane bonded to the shower substrate, forming the actual waterproof layer behind the tile.Why it matters: Tile and grout are not waterproof. This membrane is what keeps water out of your framing, and it is the single most important thing in the shower that you will never see.
- Cement board
- A rigid cement-and-fibre panel used as a tile substrate in wet areas, in place of drywall.Why it matters: Cement board is water-resistant but not waterproof — it still needs a membrane over it. A bid that lists cement board and no waterproofing has a gap in it.
- Linear drain
- A long, narrow shower drain, usually set against a wall or at the shower entry, that lets the floor slope in one direction instead of four.Why it matters: A single-plane slope is what makes large-format tile possible on a shower floor, and it is usually what makes a curbless entry drain properly.
- Curbless (zero-threshold) shower
- A shower with no raised curb, where the shower floor is recessed so water drains without a barrier at the entry.Why it matters: It is the single most effective accessibility feature in a bathroom, but it requires recessing the subfloor. On a slab that means cutting concrete; on a raised floor it means modifying joists. Feasibility, not budget, usually decides it.
- Niche
- A recessed shelf built into a shower wall, framed between studs and waterproofed as part of the shower assembly.Why it matters: Niches interrupt the waterproofing layer, so they are a common leak origin. Placement also depends on what is inside the wall — a niche cannot go where the plumbing or a bearing stud already is.
- Comfort height
- A vanity or toilet set taller than the traditional standard — roughly 34–36 inches for vanities, 17–19 inches for toilet seats.Why it matters: It reduces bending for most adults and is one of the cheapest aging-in-place improvements available, since it costs nothing extra at the time of a remodel.
- Blocking
- Solid lumber installed between wall studs to provide a fixing point for something mounted later, such as a grab bar or a floating vanity.Why it matters: Grab bars must be anchored to blocking, not drywall anchors, to hold a falling adult. Adding blocking during a remodel costs very little; adding it afterwards means opening the wall again.
- Allowance
- A budgeted amount in a proposal for an item not yet selected — tile or fixtures, for example — which is reconciled against the real cost later.Why it matters: Allowances are where bids become hard to compare. A low bid with low allowances is not cheaper; it just moves the cost to a change order. Ask what the allowance actually buys.
- Change order
- A written amendment to the contract covering work added, removed or altered after the original scope was agreed, with its own price and schedule impact.Why it matters: Change orders should be priced and signed before the work happens. Verbal changes discovered at final invoice are the most common source of remodeling disputes.
- Rough-in
- The stage where plumbing supply and drain lines and electrical wiring are installed inside open walls, before insulation and drywall.Why it matters: It is inspected before it is covered, and it is the last cheap moment to move a fixture. After rough-in passes, relocating a shower head means reopening finished walls.