How to Regrout Tile
Remove at least half the old grout depth before you regrout.
By Jonathan West · reviewed 2026-11-10 ·how we research these
To regrout tile, cut out at least half the depth of the existing grout, clean and dry the joints, pack fresh grout matched to the joint width, use caulk at changes of plane, and apply a sealer to cement grout only after the required cure time. At DIY Repair Guide, we compiled the steps below from two grout manufacturers' published instructions.
Regrouting cannot repair shifting subfloors or unbonded tiles. If tiles are loose, or if cracks repeatedly run along the exact same lines, regrouting will crack again until the underlying movement stops. In those situations, you must re-bond loose tiles or reinforce the subfloor structure before new grout can hold.
How to Regrout Tile Step by Step
Follow eight sequential steps to remove failing grout, pack new material, and finish the installation cleanly. Every phase relies on proper preparation, precise curing intervals, and the correct placement of flexible caulk instead of rigid grout.
- 1. Check that no tile moves when pressed or has cracked. Firmly press down on tiles along the work area and visually inspect each piece. If any tile moves, rocks, or has broken, the tile is unbonded and must be removed and re-bonded to the substrate before you attempt to regrout.
- 2. Remove a minimum of half the joint depth using appropriate hand or power tools. As specified by LATICRETE, cut out at least half the original grout depth while taking care not to scratch the glaze or chip the edges of surrounding tiles.
- 3. Vacuum all dust and grout debris from the opened channels, wash the entire tile face and joints with clean water, and allow the assembly to dry thoroughly.
- 4. Choose a grout formulation matched to your joint width and environment. Consult manufacturer specifications: never use unsanded cement grout in joints wider than 1/8 inch, and select sanded cement or epoxy grout for broader installations.
- 5. Dampen highly absorptive tile with water before grouting if required by MAPEI guidelines. Pack the mixed grout firmly into the joints.
- 6. Allow the grout to firm in the joints for roughly 15 to 30 minutes at 70 F (21 C), depending on room temperature, humidity, and airflow. Once the material sets up, clean the surface with a damp sponge using minimal water, rinsing frequently to avoid washing out pigment.
- 7. Caulk all movement joints, inside corners, and changes of plane. Apply flexible caulk or sealant where tile meets tubs, walls, countertops, or adjoining floors instead of filling those seams with rigid cement grout.
- 8. Allow the grout to cure completely, then seal cement grout after the mandatory waiting period. Wait at least 48 hours for MAPEI cement grouts, or a minimum of 72 hours at 70 F for LATICRETE cement grouts, before applying a sealer.
How Much Old Grout to Remove
You must carefully remove a minimum of half the depth of the existing grout joint according to LATICRETE. The remaining material left at the base of the channel must be sound and firm.
A common question is whether you can simply apply fresh grout over old grout. Neither manufacturer supports skimming a thin layer over intact old grout. LATICRETE's regrouting method requires removing at least half the depth.
Power and hand tools each have a place depending on joint width and work area. LATICRETE notes that a dustless grinder equipped with a diamond cutting blade works well for clearing joints, but you must exercise great care to avoid damaging tile surfaces and edges. For narrow joints, switch to hand-held tools such as a manual grout saw, a Dremel, or a Roto-Zip tool. When cleaning dried residue out of grout joints, MAPEI specifies leaving at least 2/3 of the joint depth available for grouting.
Once the old material has been extracted, vacuum all dust and debris from every crevice. Wash the floor or wall with clean water to lift fine particulate residue, then let the surface dry completely before opening your new grout packaging.
Choosing Sanded, Unsanded or Epoxy Grout
Joint width determines the choice between sanded and unsanded cement grout.
At DIY Repair Guide, we compiled the comparison table below directly from published technical documents provided by MAPEI and LATICRETE. Review the specific width limitations and sealing requirements for each grout type before purchasing materials.
| Grout Type | Joint Width | Sealing Requirements | Source |
|---|---|---|---|
| Unsanded cement grout | Do not use in joints wider than 1/8 inch (3 mm) | Wait a minimum of 48 hours to seal (MAPEI) | MAPEI |
| Sanded cement grout | Joints wider than 1/8 inch (3 mm) | Cure minimum 72 hours at 70 F before applying sealer (LATICRETE) | LATICRETE / MAPEI |
| Epoxy grout | Check product label for approved joint widths | Does not require a grout sealer | LATICRETE |
MAPEI explicitly warns never to use unsanded grout in joints wider than 1/8 inch (3 mm). For joints wider than 1/8 inch, rely on sanded cement or epoxy alternatives.
Corners and Changes of Plane Get Caulk
Never pack rigid grout into 90-degree inside corners, seams where walls meet floors, or intersections where tile meets a tub or shower pan. MAPEI documents state that grout installed in movement joints and changes of plane cracks. Instead of grout, install flexible caulk or sealant in every change of plane.
Do not install tile over existing expansion joints. Use caulk or sealant over expansion or movement joints.
When regrouting a shower enclosure, clear all old grout and deteriorating sealant out of the perimeter corners. Clean and dry the gap completely, then pump a smooth bead of caulk along the seam.
When to Seal New Grout
Curing periods must be observed before applying any liquid sealer over new cement grout. MAPEI states that for cement grout, you must wait a minimum of 48 hours after grouting before applying a sealer, and you must follow the sealer manufacturer's label and technical data sheet. Waiting times for other grout chemistries differ, so always follow the product packaging for your specific material.
LATICRETE cement grouts, including PERMACOLOR Select, PERMACOLOR Grout, and PERMACOLOR Select NS, require a minimum cure of 72 hours at 70 F (21 C) before applying a STONETECH sealer. Check your sealer manufacturer's requirements carefully because certain formulations require an even longer cure time before application.
Epoxy grouts follow entirely different maintenance rules. LATICRETE SPECTRALOCK PRO and SPECTRALOCK 2000 IG are epoxy grouts and do not require a grout sealer.
Proper cleaning technique during the initial grouting process directly affects the final appearance. Allow grout to firm in the joints for roughly 15 to 30 minutes at 70 F (21 C), depending on environmental conditions, before wiping with a damp sponge. Do not use excess water when cleaning. Excess water can wash out pigment and lighten the shade of your grout lines. A dripping exhaust fan is a separate moisture problem covered in our guide on a bathroom exhaust fan dripping water.
When Regrouting Will Not Fix It
Regrouting cannot cure structural instability, defective framing, or failing tile adhesives. MAPEI identifies several root causes of cracked grout lines that cannot be solved by applying new grout over the existing layout.
Subfloor deflection is a cause of cracked floor grout. MAPEI notes that the subfloor must follow Tile Council of North America (TCNA) guidelines for maximum allowable deflection. Code deflection limits protect against tile cracking, and floors under tile benefit from stiffer framing. Review our reference joist span table to verify whether your floor framing meets the stiffness required for rigid tile finishes.
Movement caused by loose or poorly bonded tile will quickly destroy fresh grout. You must lift and re-bond the loose tile with fresh setting material before regrouting that section.
Other installation defects also cause persistent grout cracking. Grout should not be installed before tile-setting materials have fully cured. Tile spacers left in joints can also cause cracking. Improper mixing, as well as ambient temperature, humidity, and wind affecting the cure, can also weaken the grout structure.
This repair is not for situations where tiles are cracked, where tiles are loose, or where the wall or subfloor behind the tile is soft and water-damaged. Our practical recommendation is to remove half the joint depth and regrout only when the substrate is stiff, tiles are firmly bonded, and corners receive flexible caulk.
Common questions
Can I put grout over old grout?
No, you should not skim fresh grout directly over intact old grout. LATICRETE requires removing a minimum of half the depth of the existing joint, ensuring the remaining grout is sound and firm.
Can you regrout a shower without removing the old grout?
No, neither manufacturer supports skimming new grout over intact old grout. You must carefully remove at least half the depth of the existing grout joint, ensure the remaining base is sound, clean out the debris, and use flexible caulk along all inside corners.
Do you have to remove all the old grout when regrouting?
No, you do not have to remove all of the old material. LATICRETE specifications state that you must remove a minimum of half the joint depth, provided the remaining grout at the bottom is firm, sound, and fully intact.
Is it expensive to regrout a tile floor?
Material expenses for regrouting are limited to grout, tools, and sealer. Professional contractor costs depend on total square footage and the condition of existing joints, so obtain quotes directly from local installers.
Why do contractors not seal grout?
Cement grout must cure before a sealer can be applied. MAPEI specifies waiting at least 48 hours and LATICRETE requires a minimum of 72 hours for cement grouts, so sealing may be a later visit. Additionally, epoxy grouts such as LATICRETE SPECTRALOCK do not require sealers.
How long before you can seal new grout?
Wait at least 48 hours for MAPEI cement grouts and at least 72 hours at 70 F (21 C) for LATICRETE cement grouts before applying a sealer. Always check your specific sealer manufacturer label for required cure intervals, and note that epoxy grouts do not require sealing.