Limestone Floor Restored After 30 Years Under Carpet Glue

Limestone with black inset squares is a classic floor for a period house, and this one runs through the hallways, the entrance hall and the main rooms. At some point it was carpeted over, and the carpet stayed down for more than 30 years.

When it was finally lifted, the stone underneath was covered in a thick layer of carpet glue. The glue had also trapped years of dirt between the carpet and the stone, so the floor was patchy, grey and stained, with cracks running across it in places.

The entrance hall before and after. Note the crack across the floor in the before photo. Photos by Stonelab.

• Thick carpet glueHardened adhesive over much of the floor, which has to come off completely before any grinding or sealing.
• Trapped dirtDecades of dirt held between the glue and the stone, staining the surface.
• CracksCracks across the floor that needed filling so the finished surface would be seamless.
• An acid sensitive stoneLimestone etches with acid, so every product had to be safe on it.

Stonelab started by scraping off as much of the hardened glue as they could. That does two jobs. It removes the bulk of the adhesive, and it lets the chemicals reach the lower layers of glue directly, rather than sitting on top of the thickest part.

They then applied a combination of solvent based strippers and an epoxy remover to melt down the last layers of glue, so the remaining residue could be scraped away with ease. The aim at this stage is a completely clean stone surface. Any glue left behind would clog the grinding tools and show through the finished floor.

• Faber Dec 21A solvent based remover for wax, sealers, old treatments and greasy residues on stone, tile and porcelain.
• Faber Decera PA concentrated alkaline cleaner for greasy dirt, wax and resins. Faber pairs it with Dec 21 for double stripping of stubborn residues.
• Faber Epoxy RemoverA solvent based stripper that softens thick, cured synthetic residues such as epoxy, resins and mastics so they can be removed mechanically.

With the glue gone, Stonelab ground and resurfaced the stone to create a much flatter, more uniform floor. They passed over the floor five times, with a finer grit on each pass. Each pass removes the scratches of the one before and gradually closes the pores of the stone, which is what brings up the shine.

During this stage they also filled the cracks across the floor with an epoxy resin colour matched to the stone, then ground it smooth so the repairs sit seamlessly with the rest of the floor.

The main room before and after. Photos by Stonelab.

• Flatten firstThe first, coarser passes remove residue and level the floor so the finer grits work evenly.
• Five progressive passesSkipping grits leaves scratches that show in the final finish. Each step up refines the surface.
• Colour matched repairsTint the filler to the stone before it goes in, then grind it flush with the floor.

Once the floor had been given time to dry out properly, Stonelab applied two coats of a water based impregnating sealant. An impregnator soaks into the stone rather than sitting on top as a film, so it protects the limestone without changing its look, and it makes general cleaning and maintenance much easier going forward.

The garden room before and after. Photos by Stonelab.

• Faber Hidro 150A water based, stain proof impregnator that keeps the stone breathable and its look unchanged. Certified safe for food contact. Faber recommends applying it after Limestone Densifier for the best combined protection.
• Faber Hidro Protector MMA VOC free, water based impregnator that penetrates the full thickness of the stone, protecting against rising humidity, salts, staining and yellowing.

Hidro 150 coverage

15 to 20 m² per litre

Second coat

At least 45 minutes after the first

Surface dry

About 1 hour

Before sealing

Floor fully dry

Compare the photos through this page. The glue, grey patches and staining are gone, the cracks have disappeared into the floor, and the limestone has an even, subtle sheen right through the house. In Stonelab's words, a beautiful subtle sheen across the whole floor for an ecstatic client.

The finished floor from the entrance hall through to the main room. Photos by Stonelab.

• Clean stone: every trace of carpet glue and trapped dirt removed.
• Flat and even: five grinding passes have levelled the floor and closed the pores.
• Seamless repairs: colour matched fills ground flush with the stone.
• Protected: two coats of water based impregnator, with the natural look of the limestone kept.

Stonelab filmed the restoration. Watch the floor go from glue covered to finished.

Video by Stonelab.

A sealed limestone floor is easy to look after, as long as the cleaning products suit the stone. Limestone is acid sensitive, so the rule is simple: pH neutral products only.

• Day to daySweep or vacuum to remove grit, then clean with Faber Neugel, a neutral gel made for absorbent stone that builds dirt resistance with every clean. AlgaFloor is a no rinse alternative.
• Avoid acidsMany supermarket limescale and bathroom cleaners are acidic and will etch limestone. See why The Pink Stuff is a risk on stone.
• Spills and stainsWipe spills up quickly. For anything that marks, our stain removal guide matches the remover to the stain.
• An aftercare kitThe Complete Natural Stone and Tile Maintenance Kit has Faber Soap, AlgaFloor and Ciao Cal in one order.

Thirty years under carpet and a thick layer of glue looked like the end of this floor. A methodical approach brought it back: strip the glue completely, grind through the grits to flatten and close the stone, repair the cracks, and seal with a water based impregnator.

The key takeaways

• Scrape off the bulk of hardened glue first, so strippers can reach the lower layers.
• Combine solvent based strippers and an epoxy remover for stubborn adhesive residues.
• Grind in progressive passes to flatten the floor and build a natural sheen.
• Fill cracks with colour matched resin and grind them flush for a seamless finish.
• Let the floor dry fully, then seal with a water based impregnator and clean with pH neutral products.