Carpet

Removing Glue-Down Carpet and Carpet Tile

Scraping glue-down carpet and carpet tile: self-scoring blade sizes, bevel direction, residue rules from CRI, and when to test the adhesive.

Updated · 2 min read

Glue-down carpet comes up fastest with a scraper and self-scoring blades, which cut the carpet into strips as it lifts. The adhesive left behind decides what happens next: the new floor's maker sets how clean the slab has to be.

Old black adhesive

If there's old black adhesive under the carpet, test it before you scrape. Cutback can contain asbestos, and powered tools that raise dust shouldn't be used to remove it.[2] See Cutback adhesive and asbestos ID.

Blade setup

Start here and adjust to the carpet and subfloor.[1][4]

  • Direct-glued carpet usually takes a 6" to 14" self-scoring blade.[1]
  • Start narrow. A narrow blade cuts with less effort and usually leaves a cleaner floor; wider isn't always faster.[1]
  • Bevel up for concrete, bevel down for wood.[1] Gypcrete also takes bevel down.
  • Use a low wheel angle for carpet over plywood or other soft subfloors.[4]
  • Keep the scoring wings sharp. Self-scoring wings also make the machine a bit harder to control.[1]

More detail in Scraper blade selection.

Step by step

With the blade set, the removal goes quickly.

  1. Pull base, transitions and anything fastened down.
  2. Start at a wall or doorway and run straight passes the width of the blade.
  3. Roll and tape the strips as they come up so they don't jam the machine.
  4. If the carpet bunches instead of cutting, sharpen or replace the scoring wings.
  5. Hand-scrape edges and corners.
  6. Clean residual adhesive to what the new flooring requires.

Carpet tile

Carpet tile is usually held with a pressure-sensitive adhesive and comes up more easily than broadloom. The same scraper setup works, or tiles can often be lifted by hand. For new carpet tile, old adhesive residue has to be removed and encapsulated before the new adhesive goes down.[3]

Residue and removers

What's left on the slab matters for the next floor.

  • Skip chemical adhesive removers on a substrate that's getting new flooring.[2]
  • Check the new adhesive's and patch's requirements before you leave the job.
  • Heavy residue on concrete may need grinding; see Grinding off thinset, mastic and glue residue.

Stretched-in carpet on the same job

Stretched-in carpet over pad comes up differently. For powered pullers, score the carpet in strips 6 ft wide, narrower if it's very strong.[5] See Removing carpet and pad.

Common mistakes

Most slow removals come down to blade setup.

  • Going wide to go fast. The machine stalls and leaves more carpet behind.
  • Dull scoring wings. The carpet bunches instead of cutting.
  • Bevel up on wood. It gouges the subfloor.
  • Solvent removers on a floor that's getting new flooring.

Machines and blades we carry

These are the machines and blades most used on glue-down carpet.

References

  1. National 550 operating manual
  2. CRI 105: Residential carpet installation standard
  3. CRI 104: Commercial carpet installation standard
  4. National 5280 operating manual
  5. National 72 carpet puller operating manual

Linked PDF documents are archived copies saved by PreFloor Tools so they stay available if the publisher moves or removes them. Check the publisher's website for the latest revision.

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