How do I remove an oil stain from my concrete driveway without wrecking the surface?

Oil stains on concrete are one of the most common driveway complaints in Ottawa. Whether it's a slow transmission leak or a lawnmower spill, the key is acting quickly and using the right method for the stain's age.

Fresh Oil Stains (Less Than 24 Hours)

Act fast — oil hasn't penetrated deeply yet.

This method handles most fresh spills and costs virtually nothing.

Set-In Oil Stains (Days to Weeks Old)

Once oil has soaked into the concrete, you need stronger chemistry.

• Commercial concrete degreaser ($15 to $30 at Ottawa hardware stores) — Products like Gunk or Purple Power are designed for this. Apply, let sit for 15 to 30 minutes, scrub, and pressure wash off.
• TSP (trisodium phosphate) — Mix 15 mL per litre of hot water, apply to the stain, scrub, and rinse. Wear gloves and eye protection. TSP is effective but harsh.
• Poultice method — Mix cat litter with acetone or mineral spirits into a paste, spread it over the stain 6mm thick, cover with plastic wrap, and let sit overnight. The solvent dissolves the oil while the absorbent pulls it out. This works remarkably well on deep stains.

Deeply penetrated oil stains may never fully disappear from concrete without resurfacing. However, you can significantly fade them:

• Muriatic acid (available at pool supply stores, $10 to $20) — Dilute 1 part acid to 10 parts water, apply to the stain, let fizz for 5 minutes, and rinse thoroughly. This etches the surface slightly, removing the top stained layer. Use extreme caution — wear gloves, goggles, and work in ventilation.
• Repeat degreaser treatments — Three or four applications over a few weeks can progressively lighten old stains.

• Rust stains (from metal furniture or tools) — Use a product containing oxalic acid. CLR or lemon juice works on mild rust. Cost: $8 to $15.
• Paint drips — Scrape dried latex paint with a putty knife, then use a heat gun on stubborn spots. For oil-based paint, mineral spirits on a rag works but test a small area first.
• Leaf/tannin stains — Common in Ottawa's fall. Pressure wash with a concrete brightener containing oxalic acid.

Place a drip pan or cardboard under vehicles with known leaks. Seal your concrete driveway every 3 to 5 years to reduce oil absorption. Many homeowners in Nepean and Kanata apply a penetrating concrete sealer ($40 to $80 for a two-car driveway) that makes future stain cleanup much easier.

For stains that won't budge or if you're considering a full driveway cleaning and reseal, Ottawa Driveways can help you find local concrete specialists who serve your neighbourhood.

---

Looking for experienced contractors? The Ottawa Construction Network connects Ottawa homeowners with qualified professionals:

• 613Bins
• RenoMotion Inc.
• Grunt Work 4 Grunts
• Leeds Property Maintenance
• Regimbal