How to Grout with a Caulk Gun: A DIY Guide
Learn why a caulk gun isn’t a grout tool and how to properly grout with a float. This expert guide from Grout Maintenance covers prep, application, cleanup, and maintenance for durable, professional results.
Grouting with a caulk gun isn’t standard practice. A caulk gun is for sealants, not tile grout. To grout correctly, use a rubber grout float to press cement-based or epoxy grout into joints, then smooth and wipe away excess with a damp sponge. If edges require sealing, reserve the caulk gun for silicone caulk.
Why a caulk gun isn't the right tool for grouting
Grout and caulk serve different purposes, and using the wrong tool can ruin joints and tile surfaces. A caulk gun applies pressure to push sealant, which isn't dense or sticky enough to fill tile joints evenly. Grout requires a dense, uniform medium that can be pressed and compacted into every crevice. According to Grout Maintenance, a proper grout job relies on consistent density, correct tooling, and clean joints. Using a caulk gun for grout increases the risk of air pockets, uneven lines, and grout breakdown over time. For most tiling projects, you should complete the core grout work with a rubber grout float, then finish edges with caulk only after the grout has cured as needed. This separation keeps joints stable and helps prevent staining and shrinkage. In short: reserve the caulk gun for caulk, not grout, to achieve durable, professional results.
Note: The guidance below aligns with best practices from Grout Maintenance to help homeowners and DIY enthusiasts achieve lasting tile work.
block
Tools & Materials
- Grout (cement-based or epoxy)(Choose unsanded for small joints (<1/8 inch) or sanded for wider joints)
- Grout float(Rubber float with beveled edges for press-fit into joints)
- Margin trowel or mixing paddle(For mixing grout in a bucket)
- Bucket(Clean container for mixing grout)
- Sponge(Damp, clean sponge for wiping haze and smoothing joints)
- Water spray bottle(Mist water for smoothing and cleanup)
- Caulk gun(Reserved for silicone caulk along edges after grouting)
- Silicone caulk(Use for gaps around fixtures or perimeter edges after grouting)
- Utility knife(To remove stubborn old grout)
- Gloves and eye protection(Protect hands and eyes from dust and chemicals)
Steps
Estimated time: 60-90 minutes
- 1
Prepare joints and remove old grout
Clear the joints of loose grout with a grout saw or oscillating tool. Vacuum or wipe away dust until the joints feel clean and dry. This creates a solid base for new grout and reduces staining from debris.
Tip: Wearing eye protection helps ward off chips and dust; work in a well-ventilated area. - 2
Mix grout to the correct consistency
Combine grout powder with water (or activator for epoxy) according to the manufacturer's instructions. Mix to a thick, peanut-butter consistency and let it slake for a few minutes, then remix briefly to a smooth, workable paste.
Tip: Avoid adding extra water to loosen the mix; too much water weakens the grout and can cause cracking. - 3
Pack grout into joints with a float
Load the grout onto the float and press it firmly into the joints with a 45-degree angle. Work in small sections to ensure the grout fully penetrates each joint without gaps. Remove excess grout from the tile face as you progress.
Tip: Keep low, steady pressure to avoid air pockets; work from the center outward toward edges. - 4
Clean joints and finish
After the joints have filled, hold the float at a low angle to strike off excess and smooth the lines. Wipe tile faces with a damp sponge in a circular motion to remove grout haze. Allow the grout to cure per product instructions before sealing or subjecting to traffic.
Tip: Rinse the sponge frequently to prevent haze transfer; avoid wetting joints with excess water.
Got Questions?
Can I use a caulk gun to grout tile joints?
No. A caulk gun is designed for sealants and flexible caulk, not the rigid filling required for tile joints. Grout should be pressed into joints with a grout float and then cleaned. A caulk gun is better suited for silicone around edges after grouting.
No, use a grout float for grout and reserve a caulk gun for caulk along edges after grouting.
What grout type is best for showers?
Epoxy grout offers superior stain resistance and durability in wet areas but requires precise mixing and cleanup. Cement-based grout is easier to work with for most DIY projects, with acrylic modifiers available for extra water resistance.
Epoxy grout lasts longer in showers, but cement-based grout is easier for beginners.
How long should grout cure before sealing?
Cure times vary by product and environment; always follow the manufacturer’s instructions. In most cases, you wait until the grout reaches its rated hardening state before applying any sealer, if applicable.
Cure times depend on the product—check the label before sealing.
Why do grout lines crack after sealing?
Cracks often result from movement in the substrate, improper mixing, or using too much water during cleanup. Ensure proper substrate preparation and allow full cure before applying sealers.
Cracks usually come from movement or poor prep; fix by re-grouting after addressing movement.
How can I remove grout haze from tiles without scratching?
Wipe haze with a damp sponge promptly after tool removal, using clean water. For stubborn haze, use a mild grout haze remover or a tile-safe cleaner following manufacturer directions.
Wipe off haze with a damp sponge as you go; if stubborn, use a safe cleaner.
Is caulking required after grouting?
Caulk is often used around edges and corners after grouting, especially in showers and tubs, to accommodate movement and prevent water intrusion. Do not mix this with grout in the same joints.
Yes, seal around edges with caulk after grout, but keep grout and caulk separate.
Watch Video
The Essentials
- Grout with a float, not a caulk gun.
- Prepare joints thoroughly before applying grout.
- Choose the right grout type for the space.
- Seal or caulk only after grout cures and is clean.
- Inspect joints for uniformity and finish.
