How to Install an Over the Range Microwave with a Granite Backsplash

Installing an over the range microwave oven with a granite backsplash requires careful planning and execution. Proper installation ensures safety, functionality, and an integrated look for your kitchen. Follow these steps to successfully install your over the range microwave oven against a granite backsplash.

Choose the Right Microwave Oven Model

When selecting your over the range microwave, ensure it is designed for installation with a granite, stone, or other solid surface backsplash. Standard microwaves have ventilation at the top rear which must remain unobstructed. Microwaves made for granite backsplash installation shift the ventilation to the bottom or side.

Consider the size and dimensions of the microwave to find the right fit for your available space. Measure the height, width, and depth of your space to ensure proper clearance above and on the sides for ventilation. Select a microwave with at least 1 inch of clearance on each side and several inches above after installation.

Microwaves come in multiple finish options. Select a finish which matches or complements your kitchen décor and granite backsplash color. Stainless steel, black, white, and stainless with black trim are common finish options.

Once you’ve selected the ideal over the range microwave model, check that the electrical supply at the installation location can support the appliance. Microwaves usually require a dedicated 120V, 60Hz, 15 or 20 amp electrical circuit.

Prepare the Installation Space

Remove existing microwave: If you are replacing an existing over the range microwave oven, uninstall it prior to installation following the manufacturer’s instructions. This usually involves removing screws or clips securing it to the wall or cabinet and disconnecting the electrical supply.

Clean the area: Thoroughly clean the wall area and underside of the cabinets where the microwave will be installed. Remove any dust, grease or debris. This allows the microwave to mount flush against the wall.

Create electrical access: If needed, install an electrical outlet in the upper cabinet above the microwave location. Position it to align with the power cord outlet on the rear of the microwave. Use a UL listed outlet with ample load capacity for a microwave.

Pre-drill vent holes: To allow for proper ventilation, your granite backsplash will need vent holes aligned with the outlet on the rear or bottom of the microwave. Consult your microwave manual for the vent location and size requirements. Mark and pre-drill uniform holes in the granite.

Protect cabinets: Cover the area under the cabinets with protective material like plastic sheeting or cardboard. This shields against dust and debris during the installation process.

Install the Microwave

Mount the brackets: Per your microwave’s instructions, secure the mounting brackets and hanging plate to the microwave chassis. Some models have removable mounting plates while others have integrated mounting hardware. Position them according to your cabinet configuration.

Lift into place: With assistance, gently lift the microwave into position against the wall, allowing the mounting plate to rest on the bottom of the upper cabinets. Temporarily secure with tape if needed.

Connect ducting: If your microwave recirculates internally, skip this step. If it vents externally, connect aluminum ducting to the vent outlet according to manufacturer guidelines. Run the ducting to a cutout in the exterior wall. Seal connections with aluminum tape.

Make electrical connection: Plug in the power cord to the outlet installed in the upper cabinet. For direct wire connections, access the microwave junction box and connect wires per local codes. Verify correct polarity. Leave wires coiled behind.

Secure mounting: From inside the upper cabinet, place bolts through the mounting plate or brackets and tighten securely. Use lock washers or nuts to prevent loosening over time. Install any required additional support brackets.

Check for levelness: Verify the microwave is level side to side and front to back. Make any necessary adjustments before finalizing the installation. The microwave should be flush against the wall.

Finalize ducting: For external venting, seal any gaps around the ducting with aluminum tape to prevent exhaust air leaks into the cabinet. Secure the ducting with clamps.

Complete electrical: For a direct wired connection, tuck all wires neatly into the junction box, secure the cover, and install the microwave chassis. Restore power and test operation.

Integrate Microwave with Granite Backsplash

Proper finishing ensures a clean, integrated look between your microwave and granite backsplash.

Caulk edges: Apply a thin bead of silicone caulk along the top and side edges where the microwave meets the granite. Smooth with a wet finger or tool for a seamless appearance.

Apply trim kit: Microwave trim kits cover installation gaps andexposed edges. Carefully measure and cut pieces to fit per included template and instructions. Snap into place or adhere with adhesive.

Add backsplash panels: Decorative stainless, glass, or other backsplash panels screw into place over the top of the microwave for a custom look. Follow manufacturer’s guidelines for appropriate panel size and installation.

Check ventilation: Verify proper airflow by testing microwave ventilation pre and post-installation. Modify ducting or vent holes as needed to achieve adequate ventilation.

Complete protection removal: Remove any protective coverings from the cabinets, countertops, or walls. Clean any caulk, adhesive, or debris. Touch up paint as needed.

Test operation: Run a microwave operational test with various power levels and cooking modes. Ensure internal components like turntables function properly. Your microwave should operate flawlessly.

Microwave Installation Tips

Follow these additional tips for proper over the range microwave installation:

  • Allow ample overhead clearance from the cooking surface based on manufacturer guidelines, usually at least 66 inches.
  • Install the bottom of the microwave at least 30 inches above the cooking surface per standard safety code.
  • Only mount the microwave to wood or metal cabinetry, not to drywall alone.
  • Use a dedicated grounded electrical circuit for the microwave with suitable amperage rating.
  • Keep duct runs short and straight as possible with minimal bends for optimal external ventilation.
  • Secure duct joints with aluminum tape to prevent exhaust leaks into cabinets or walls.
  • Avoid flexible ducting which can sag and impede ventilation. Use rigid metal ductwork only.
  • Seal all holes in the upper cabinet for wires, ducting, and bolts to contain airflow.
  • Make sure the microwave location is free from pipes, electrical lines, or other elements in the wall cavity.
  • Never leave the microwave unsupported by the mounting plate while open. Have an assistant help stabilize it.
  • Use hand tools for installing upper cabinet bolts to avoid over tightening and damaging threads.
  • If reusing existing vent ducting, thoroughly clean it out first to remove grease buildup.

Following proper installation techniques for your over the range microwave against a granite backsplash provides a safe, visually pleasing, and fully functional addition to your kitchen. Pay close attention to all instructions and dimensions for a seamless installation.

Frequently Asked Questions About Installing a Microwave with Granite Backsplash

How is installing a microwave oven with a granite backsplash different than a regular wall?

The solid surface of granite requires pre-drilling vent holes aligned with the microwave’s ventilation outlet. Standard installations allow ventilation through the space between wall studs. Granite must be precisely cut to prevent obstruction.

What mounting bracket is best to support a heavy microwave on granite?

Look for a reinforced mounting plate at least 3/16 inches thick with sufficient support across the bottom and heavy gauge end brackets. Stainless steel hardware provides strength. Spread load over multiple studs.

Should I caulk the gaps between the microwave and granite backsplash?

Yes, use silicone caulk rated for kitchen use to seal any gaps along the top and sides. This prevents cooking splatters, grease, and debris from accumulating in cracks. Smooth the caulk with a finger before drying.

How do I cut ventilation holes through granite backsplash?

Use a specialized granite wet core drill bit made for plumbing and electrical cutouts. Cool the bit with water while cutting slowly through the stone. A diamond core bit also works. Cut holes 1/8 inch larger than required.

Can I install my microwave directly over a cooktop on the same granite surface?

Yes, building codes allow combining a microwave and cooktop on the same granite backsplash wall. Maintain at least 2-3 feet horizontal distance between the appliances and meet overhead clearance requirements.

Is it okay to mount the microwave directly to granite without upper cabinets?

Microwaves installed without upper cabinet support require a special granite mounting kit. This anchors to the granite rather than resting on a cabinet. Ensure the granite is adequately secured to wall studs.

Where should I position the outlet on the microwave when installing into granite?

Aim to place the outlet near the center of the drilled ventilation holes, aligned vertically to allow the shortest duct run. Avoid overlapping seams in granite panels which can fracture during drilling.

Can I install decorative glass panels over the microwave against granite?

Yes, specialized glass panels fit over the upper portion of your microwave to integrate it with the look of glass backsplash. Use the manufacturer’s template and hardware. Leave the vents uncovered.

What depth granite backsplash do I need for over the range microwave installation?

The granite backsplash only needs to be 1 to 1.5 inches thick to support a mounted microwave. Thicker granite is acceptable but may require longer mounting bolts and specialty drilling tools.


Installing an over the range microwave against a granite backsplash introduces some unique considerations but can significantly upgrade your kitchen’s functionality and visual appeal when done properly. Careful planning of the microwave model, outlet position, vent placement, and finishing details helps ensure success. Following the manufacturer’s instructions paired with the tips provided above allows you to safely and seamlessly combine these two elements. Microwave and granite can come together to create a professional built-in look for your kitchen.