Stone Soap
- What it is: A concentrated, pH-neutral, biodegradable heavy-duty cleaner that removes dirt, grime, mineral deposits, and efflorescence without damaging finished or unfinished surfaces.
- Best for: Prepping concrete, natural stone, tile, and grout before applying any SEMCO sealer, stain, or waterproofing product — and for general surface cleaning and maintenance.
- Stands out because: Neutral pH means no acid-etch damage or adhesion-killing residue, works in hard or soft water, and is 100% biodegradable and safe for confined spaces.
- Keep in mind: It's a cleaner, not an acid etch — for surfaces that genuinely need chemical etching, SEMCO's guidance is still to avoid muriatic acid, since acid residue is a common cause of coating adhesion failure.
- Keep in mind: It's a rejuvenating topcoat, not a structural repair or a permanent refinish — expect to recoat periodically to maintain the shine, and always test on an inconspicuous area first.
Shipped From USA
100% Biodegradable
Low Odor & Low VOC
Made in USA- Cleans without damaging the surface. A concentrated, neutral-pH formula that lifts dirt and grime without etching, discoloring, or degrading finished surfaces the way acidic cleaners can.
- The right prep step for every SEMCO coating. Whether you're about to apply SEMCO Liquid Membrane, PreStain Color, Titan Shield Gloss, Natural Shield, or Sealer Matte, Stone Soap (often paired with Nu-Lift Cleaner or Power Cleaner depending on the substrate) is the recommended first step.
- Works in hard or soft water. Performance doesn't depend on your local water chemistry.
- 100% biodegradable. Breaks down naturally and is safe to use in confined or occupied spaces.
- No harsh rinsing chemicals required. Simple dilution with water, applied with a standard pump sprayer.
- One of SEMCO's founding products. Part of the original three-product lineup the company launched with in 1991 — over three decades of use in the field.
Cleaning Performance
- Concentrated, heavy-duty formula that removes dirt, grime, mineral deposits, and efflorescence.
- Neutral pH — won't etch or damage finished or delicate surfaces.
- Equally effective in hard or soft water.
Health & Environmental
- 100% biodegradable.
- Can be safely used in confined environments.
- User-friendly, environmentally-responsible formula.
Practical Use
- Doesn't need to be rinsed off to remain effective, though rinsing before coating is still recommended.
- Simple dilution ratio and application with a standard pump sprayer.
- Suitable for countertops, floors, concrete, stone, tile, and more.
- Concrete and masonry surfaces — remove mineral deposits and efflorescence before applying a sealer, stain, or waterproofing membrane.
- Natural stone and ceramic tile/grout — clean without etching or dulling the finish.
- Existing sealed or coated surfaces — general cleaning and maintenance without degrading the existing finish.
- Prep before SEMCO Liquid Membrane, PreStain Color, Titan Shield Gloss, Natural Shield, or Sealer Matte — the standard first-step cleaner in SEMCO's surface-prep process (often paired with Nu-Lift Cleaner for mineral deposits/efflorescence, or Power Cleaner where there's oil or grease).
- Countertops, floors, and general household/commercial surfaces — everyday cleaning beyond just pre-coating prep.
- Gather materials and prep the space. Ensure the surface is free of debris.
- Mix the solution. Combine 1 part Stone Soap with 4 parts water.
- Pre-dampen the surface with plain water — this keeps the cleaner from penetrating too deep into the substrate's pores.
- Apply the Stone Soap mixture lightly with a pump sprayer and let it sit for 2–3 minutes.
- Scrub the surface using a scrub machine or nylon brush.
- Rinse thoroughly, making sure no residue is left behind.
- Let the surface fully dry before applying any sealer or coating.
Additional notes: Do not use muriatic acid to prep surfaces — acid residue can cause coating adhesion problems. Getting a surface properly pH-balanced before coating is critical for adhesion and performance, which is why SEMCO recommends its standard prep methods (like Stone Soap) over acid washes.
PRODUCT INFO
SEMCO Stone Soap is a highly concentrated, heavy-duty, pH-neutral cleaner built to strip dirt, grime, mineral deposits, and efflorescence from a surface without harming or etching what's underneath. Unlike acid washes, it won't leave behind residues that compromise adhesion, and unlike many commercial degreasers, it's 100% biodegradable and gentle enough for confined spaces.
It's one of SEMCO's three original products — Stone Soap, Power Cleaner, and Nu-Lift Cleaner were the company's founding lineup back in 1991 — and it remains the standard first step in prepping concrete, natural stone, tile, and other surfaces before applying SEMCO Liquid Membrane, PreStain Color, Titan Shield Gloss, or any other sealer in the lineup. It works equally well in hard or soft water and doesn't require rinsing to remain effective, though rinsing is still recommended before coating.
- Type – Concentrated, pH-neutral cleaning solution
- Coverage – Up to 250 sq ft/quart, up to 1,000 sq ft/gallon, up to 5,000 sq ft/5-gallon pail
- Dilution - 1 part Stone Soap to 4 parts water
- Biodegradability - 100% biodegradable
- Application tools – Pump sprayer, scrub machine or nylon brush
- Shelf life – 2 years in controlled ambient storage (60–72°F)
How Stone Soap Compares to Other Surface-Prep Methods
Stone Soap is positioned specifically as a safer alternative to acid-based surface prep. Here's how a neutral-pH cleaner concentrate compares to the other common surface-prep chemistries, based on published, sourced information (not a specific named competing product).
| SEMCO Stone Soap (Neutral-pH Cleaner Concentrate) |
Muriatic Acid Wash | Solvent-Based Degreaser | |
|---|---|---|---|
| pH | Neutral | Strongly acidic; requires neutralization after use | Not pH-based; strong solvent chemistry |
| Risk of adhesion failure from residue | Low — no acid residue to trap in pores | Real risk — residual chloride salts and unneutralized acid can cause osmotic blistering and adhesion failure under coatings | Can leave oily residue if not fully rinsed |
| Safe for finished/delicate surfaces | ✓ | ✗ Etches and can damage finished surfaces |
Varies — can dull or discolor some finishes |
| Biodegradable | ✓ 100% |
✗ Hazardous waste disposal considerations for acid rinse water |
✗ |
| Safe for confined spaces | ✓ | ✗ Fumes require ventilation and PPE |
✗ Solvent fumes require ventilation |
| Rinse required | Recommended before coating, not required for effectiveness | Required, and must be fully neutralized, not just rinsed | Required |
This comparison reflects general, publicly available information about surface-prep chemistries as a category, not a specific competing branded product.
SEMCO Liquid Membrane™ is trusted by professional waterproofing contractors, builders, pool service companies, property managers, and facilities teams across the country. We offer dedicated support and volume pricing for businesses.
Benefits List
- Volume discount pricing on 5-gallon pails and case ordersPriority technical support from application experts
- Fast reorder history and account management
- Co-branded project documentation and spec sheets available
- Suitable for: waterproofing contractors, pool builders, property maintenance, HOAs, facility managers
CTAs
- Enquire About Pro Pricing → CONTACT US
- Call Us: 1-833-211-2297
The full version
Detailed application instructions.
Pick your project. Every step, with the detail you’ll want while you’re actually doing it.
01 Clear the surface
You’ll need: Stone Soap · stiff nylon brush · pump sprayer
Prep A is for dirt and grime, and for new concrete that has fully cured (about a month).
- Sweep or blow off loose debris.
- Mix 1 part Stone Soap to 4 parts water.
02 Wash
- Lightly dampen the surface with water first — it stops the cleaner soaking deep into the pores.
- Apply the Stone Soap mix with a pump sprayer and let it sit 2–3 minutes.
- Scrub with a nylon brush or scrub machine.
- Rinse well and make sure no residue is left.
03 Dry, then coat
Let the surface dry completely before any SEMCO coating goes on — below 3% residual moisture.
| Use for | Dirt and grime · new concrete |
| Products | Stone Soap |
| Mix | 1 part Stone Soap : 4 parts water |
| Dwell time | 2–3 minutes |
| Before coating | Fully dry · under 3% moisture |
01 Mix both cleaners
You’ll need: Power Cleaner · Stone Soap · nylon brush · pump sprayer
Prep B is for grease, oil, weathering and tough build-up — and for EPDM, TPO, shingle and bitumen roofs, and for re-prepping cured SEMCO membrane before an extra coat.
- Power Cleaner: 1 part to 4 parts water.
- Stone Soap: 1 part to 4 parts water.
02 Degrease with Power Cleaner
- Lightly dampen the surface with water.
- Apply the Power Cleaner mix with a pump sprayer and let it sit 2–3 minutes.
- Scrub with a nylon brush or scrub machine.
- Rinse well until no residue is left.
03 Follow with Stone Soap
Repeat the same steps with the Stone Soap mix. It lifts the chemical residue Power Cleaner leaves behind and rebalances the surface pH.
04 Dry, then coat
Let the surface dry completely — below 3% residual moisture — before coating.
| Use for | Grease, oil, weathering · EPDM, TPO, shingle, bitumen |
| Products | Power Cleaner, then Stone Soap |
| Mix | Each 1 part : 4 parts water |
| Dwell time | 2–3 minutes each |
| Before coating | Fully dry · under 3% moisture |
01 Clear and dampen
You’ll need: Nu-Lift Cleaner · Stone Soap · nylon brush
Prep D is for efflorescence, mineral deposits and oxidation — basements, block, brick, stucco, weathered concrete — and for metal, which Nu-Lift etches so the coating bonds.
- Remove loose paint, dust and debris.
- Lightly wet the surface with water.
02 Nu-Lift, undiluted
- Apply Nu-Lift Cleaner undiluted and let it sit 2–3 minutes.
- Scrub with a nylon brush or scrub machine.
- Rinse well.
03 Stone Soap to finish
- Mix 1 part Stone Soap to 4 parts water, apply and let it sit 2–3 minutes.
- Scrub, then rinse until no residue is left.
Stone Soap clears the residue Nu-Lift released and rebalances the surface pH.
04 Dry, then coat
Let it dry completely — hours, not minutes — to below 3% residual moisture.
| Use for | Efflorescence, mineral deposits · metal |
| Products | Nu-Lift, then Stone Soap |
| Mix | Nu-Lift undiluted · Stone Soap 1:4 |
| Dwell time | 2–3 minutes each |
| Before coating | Fully dry · under 3% moisture |
Need a hand? Call 1-833-211-2297 or email info@semcoworks.com — the team will check prep, coverage and cure timing before you start.
Before you buy
The questions worth asking.
What is SEMCO Stone Soap?
Stone Soap is a highly concentrated, 100% biodegradable, pH-neutral cleaner formulated to clean finished surfaces without harming them.
What can I clean with Stone Soap?
It safely cleans natural stone, concrete, tile, and other finished surfaces, and is used as a prep step alongside Power Cleaner or Nu-Lift Cleaner.
How much does Stone Soap cover?
One quart covers up to about 250 sq ft, one gallon up to about 1,000 sq ft, and a 5-gallon up to about 5,000 sq ft, diluted per the label.
Is Stone Soap safe for finished surfaces?
Yes. Its pH-neutral, biodegradable formula cleans without stripping or damaging sealed or finished surfaces.
More questions? Browse every SEMCO FAQ.
