Three kinds of concrete floor
- Bare or worn slab
- Porous; absorbs residue and spills, often with old oil stains from industrial use
- Sealed slab
- Topical sealer forms a skin; residue sits on top unless the sealer is worn through
- Polished concrete
- Ground and densified; holds little residue but the joints and edges still collect film
- Quick test
- A drop of water that soaks in and darkens the floor means it is porous there
Why the floor matters in a loft
Converted warehouse lofts in RiNo often keep the original slab, sometimes ground smooth, sometimes left rough with its history showing. Newer mixed-use buildings frequently have concrete floors too, on the upper floors of a podium or as a polished finish in ground-level units. Cannabis and tobacco smoke residue settles out of the air onto every horizontal surface, and a floor is the largest horizontal surface in the room.
On a bare slab, settled residue mixes with dust and is ground into the pores by foot traffic. On a sealed or polished floor most of it stays on the surface, so regular damp mopping removes it. Trouble spots on any concrete floor are the control joints and cracks, the gap where the slab meets the wall, and areas under rugs, where residue that soaked through the rug sits against the slab for months. Old industrial floors can also carry their own odors, like machine oil, that people sometimes mistake for stale smoke.
Deciding what your floor needs
Start with the water drop test in several places, including under where furniture and rugs sat.
- IfWater beads up everywhere and the floor smells fine once rugs are removedThenDamp mop with a mild cleaner, clean joints with a narrow brush, and focus effort elsewhere in the loft.
- IfWater beads in traffic areas but soaks in near walls or under old rug spotsThenThe sealer has worn unevenly. Clean thoroughly, let it dry, and ask about recoating the floor once odor is gone.
- IfWater soaks in everywhere and the floor smells when warmThenExpect a deeper cleaning with a concrete-appropriate cleaner and scrubbing machine, followed by sealing to keep new residue on the surface.
- IfDark stains smell of oil rather than smokeThenThat is likely an old industrial stain. It needs a degreaser or poultice, not smoke treatment, and may never fully disappear.
- IfYou rent and the floor is the landlord's finishThenClean only with mild products and ask before using anything that could etch or change the finish.
A sensible order for a porous slab
- Clear and vacuum.Move furniture and rugs, then vacuum with a brush head so grit does not get scrubbed around as an abrasive.
- Clean the edges and joints by hand.Use a stiff nylon brush and a vacuum crevice tool along walls and in control joints, where residue and dust pack in.
- Scrub the field.A floor machine or deck brush with a cleaner suited to concrete, followed by a wet vacuum to lift the dirty solution rather than letting it dry back in.
- Dry and re-check.Let the slab dry fully, then smell it with the heat on and the windows shut before deciding about a sealer.
- Seal if appropriate.A penetrating or topical sealer chosen for the floor's look and traffic makes future cleaning simple. Confirm the floor is dry and residue-free first.
General information for RiNo, not a quote or professional advice. In an emergency, call 911.