
1. Prep the Surface First
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- Substrate must be clean, dry, level, and structurally sound (granite is heavy, so weak or flexing surfaces cause cracks later).
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- Remove dust, grease, old adhesive, and any loose material.
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- For floors, check with a spirit level or straight edge — granite doesn’t hide an uneven base well.
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- On plywood or wood subfloors, add a cement backer board first; granite needs a rigid base.
2. Choose the Right Adhesive
Granite is dense and heavy, so ordinary adhesive won’t do:
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- Use a high-strength TeraMix TM 333 Tile & Granite Adhesive, polymer-modified thin-set mortar (not a standard tile adhesive meant for ceramic).
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- For large slabs or countertops, consider epoxy-based adhesive for maximum bond strength and minimal shrinkage.
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- White thin-set is preferred for light-colored or polished granite to avoid discoloration showing through.
3. Back-Butter the Granite
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- Apply adhesive to the substrate with a notched trowel (larger notch size for bigger slabs — typically 1/2″ x 1/2″ or bigger).
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- Also apply a skim coat directly to the back of the granite piece (“back-buttering”). This ensures full, even contact and prevents hollow spots (lippage or cracking under weight).
4. Set the Granite Carefully
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- Press each piece firmly, using a slight twisting motion to seat it and push out air pockets.
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- Use a rubber mallet and a wood block to tap it level — never hit granite directly, it can chip.
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- Use spacers for consistent grout lines (or push slabs edge-to-edge for a seamless look on countertops).
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- Check level constantly as you go — granite is unforgiving once adhesive sets.
5. Support Overhangs and Joints
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- For countertops with overhangs beyond 6–8 inches, add plywood or corbel support underneath.
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- Seams between slabs should be reinforced with seam adhesive/epoxy and clamped until cured.
6. Let It Cure Properly
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- Don’t walk on floor tiles or use countertops for at least 24–48 hours.
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- Full cure (for grouting or heavy use) typically takes 48–72 hours, depending on adhesive type and humidity.
7. Seal Before Grouting
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- Granite is porous — seal it before grouting to prevent grout haze and staining.
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- Grout joints once adhesive has cured, then apply a second sealant coat after grouting.
