What’s really in your shower.
Five materials, side by side, straight from the published data sheets. Mine on the left, the shortcut on the right. Every number is sourced.
On strength, they’re neck and neck. The generic bag just won’t tell you anything else, and it asks you to bring your own polymer. It’s a cake mix that says “add eggs.”Compressive strength is similar. 3701 also publishes flexural strength, absorption and shrinkage, and comes polymer-fortified; typical sand mixes don’t.
Flexural strength
How much bending the bed takes before it cracks. Your floor flexes a little every day: joists deflect, heavy tile and glass sit on it, people walk on it.
Ask a generic bag how much it bends before it cracks. It doesn’t say. That silence is the answer you’re standing on.If a maker doesn’t publish flexural strength, there’s no spec to hold it to.
| Mine | The shortcut | |
|---|---|---|
| Polymer | Built in. Just add water | Add fortifier on site |
| Water absorption | < 5% | Not published |
| Shrinkage (7 day) | 0.05% | Not published |
| Service rating | TCNA Extra Heavy | Not published |
Hand-packed 3701 on Laticrete’s own detail: cleavage membrane, wire mesh mid-bed, 2″ minimum. Sloped to your room, rebar in the curb, under Hydro Ban, flood tested.
Cement grout drinks. Shampoo, soap scum and body oils ride in with the water. Epoxy soaks up about 0.05 g; the limit for basic cement grout is 10 g.Cement grout is porous and usually needs sealing. Cured epoxy absorbs about 0.05 g under ISO 13007, against a 10 g limit for basic cement grout.
| Mine | The shortcut | |
|---|---|---|
| Sealing | Never needs sealing | Sealer recommended |
| Stains | “Stainproof” (residential) | “Not absolutely stain-resistant” |
Honest catch: epoxy is harder to install (80 min working time at 21 °C, 30 min at 35 °C), can darken white marble, and shouldn’t see steam over 121 °C.
Epoxy in the shower. No sealer, no resealing, soap scum wipes off.
The mix matters
That 5,000 psi is a lab number: mixed to the sheet, packed tight, cured right. Extra water makes weaker paste. Too dry to pack means trapped air, and every 1% of it costs about 5% of the strength. Leave enough in and you’ve built a very expensive sandbox.Published strength assumes the bed is mixed, compacted and cured to spec. More water lowers strength; trapped voids cost about 5% per 1%; cement only gains strength with moisture and a reasonable temperature. A bed mixed or packed wrong can end up well below its rating, and sandy.
- 2 to 3.2 quarts of water per 60 lb bag for floors. Stiff, semi-dry.
- Mix 2–3 min, slake 5, remix 2–3 “without adding any water or powder.”
- Over wood: cleavage membrane, half the bed, 2″×2″ 16-ga mesh, the rest. 2″ minimum.
- “Compact well.” Slurry bond coat on edges from yesterday’s work.
- 40–90 °F only. Protect it longer in the cold; dampen and cover in the heat.
- Wait: 12 h to walk on, 72 h before the liquid membrane.
“I’ve dug out shower beds that crumbled like beach sand.”
Basic thinset is regular unleaded: 150 psi of bond to porcelain is all its standard asks for. My wet zones get the premium tank.ANSI asks 150 psi (A118.1), 200 psi (A118.4) and 400 psi (A118.15) of 28-day bond to porcelain. 254 Platinum is published at 475–575 psi.
| Mine | The shortcut | |
|---|---|---|
| ISO class | C2TES2P1 | Typically C1 |
| Tensile after water immersion | 1.3–1.5 MPa | C1 min 0.5 MPa |
| Large & heavy tile | MULTIMAX Lite (A118.15HET) | Not an “H” mortar |
| Over Hydro Ban | Approved Laticrete mortar | Membrane calls for latex thinset |
| For showers, per the maker | “Underwater applications” | “Mix with” latex admix |
254 Platinum on every shower floor and the first foot of every wall. Above that, still a Laticrete mortar approved over Hydro Ban: 254 Platinum, or MULTIMAX Lite for large & heavy tile.
Fast, easy, and nobody’s proud of it. Factory slope, the drain goes where the box says, and the curb holding your ~120 lb glass panel? The makers suggest gluing the hardware on.FOAM trays come in fixed sizes and drain positions and are very light and fast. A mortar bed is shaped to any room and drain, and a rebar-reinforced curb gives glass hardware solid anchoring.
| Mine | The shortcut | |
|---|---|---|
| Size & drain | Any room, any drain, curbless | Fixed sizes; extend with dry-pack |
| Small mosaics | No published bed minimum | Extra support or min sizes apply |
| Glass on the curb | Anchor into mortar + steel | Epoxy, not screws, or anchor track |
| Weight | 144 lb/ft³ | 3.75 lb/ft³ (FOAM wins) |
“A system warranty covers the product, and only if every step was done their way. Mine covers my workmanship: a 25-year warranty on tile-setting workmanship.”
Your shower moves a little every day. Grout is rigid, so grout in a corner cracks like a dad joke at a wedding. The industry method (TCNA EJ171) wants flexible sealant at every corner and change of plane. A basic latex caulk doesn’t even get a movement rating. LATASIL is tested to stretch and squeeze ±25%. One is a sealant; the other is toothpaste with ambition.Tile assemblies move slightly with heat, moisture and floor deflection. TCNA EJ171, referenced in Laticrete’s Hydro Ban instructions and system warranty, calls for flexible sealant joints at corners, changes of plane, perimeters and penetrations, not grout. LATASIL is a 100% silicone rated ASTM C920 Class 25 (±25%). Basic latex caulks are made to ASTM C834, which has no movement class.
| Mine | The shortcut | |
|---|---|---|
| Standard | ASTM C920 Type S, NS, Class 25 | ASTM C834 (latex) |
| Under water | Pools & wet areas; submersion after 4 days | “Prolonged water immersion” listed as a limitation |
| Wet-area primer | LATASIL 9118 Primer | None published |
| Colour | All 40 Laticrete grout colours + clear | Typically clear & white |
| Full cure | Tack-free 17 min; 4 days to submersion | 7 to 14 days |
| Shrinkage | C920 caps weight loss at 7% | “Low to moderate”; one sheet: 25–28% by volume |
| Part of the Hydro Ban system | Named for drains & movement joints | No |
| Paintable | No | Yes (latex wins) |
Fair is fair: some siliconized caulks and general-purpose silicones are tested to C920 too. The red bubble is the basic C834 latex type. And latex caulk paints; silicone doesn’t.
“I’ve seen LATASIL joints still looking brand new after 10 years in a shower.”
LATASIL at every corner, curb, drain and change of plane, colour-matched to your grout, over backer rod where it’s deep, on LATASIL 9118 Primer in every shower. No grout in the corners. Ever.
What a “system warranty” actually covers
It sounds like a force field. It reads like a gym membership.Published system warranties typically cover products against manufacturing defects, with conditions.
- Their parts only. Substitutions can void it
- Installed exactly to their handbook
- Some need a certified installer, registration within 30 days, and photos
- Installer workmanship: not covered
- Water damage to the rest of the house: excluded
- Subfloor and structural issues: excluded
- Payout capped at the original per-sq-ft install cost
- Written notice within 30 days of a defect
Fair is fair: the system warranty on the Laticrete products I use works the same way.
