How to Drill a Wall Vent – A Step-by-Step DIY Guide

By Robert Mac

Wondering how to drill a wall vent for a bathroom extractor, kitchen hood, or tumble dryer? This step-by-step guide will show you exactly how to drill through brick, block, or cavity walls cleanly and safely — using the right tools and proven techniques.

Why You Might Need to Drill a Wall Vent

Wall vents help improve airflow, reduce condensation, and prevent dampness in moisture-prone rooms. Whether you’re installing a cooker hood or a mechanical fan, you’ll likely need to drill a wall vent to route air outside properly.

With the correct tools and a clear plan, it’s a manageable DIY task — especially when you hire equipment rather than buy it.

Tools and Materials You Will Need

  • Core drill (rotary mode only)

  • Diamond core bit (100–125 mm)

  • SDS drill with long masonry bit (10–12 mm x 400–600 mm)

  • Wall scanner or pipe detector

  • Dust mask, gloves, safety goggles, hearing protection

  • Spirit level, measuring tape, chalk or marker

  • Ventilation kit (duct sleeve, internal flange, external grille)

  • Plastic sheeting or dust sheets

  • Exterior-grade silicone or expanding foam

Tip: If you only need these tools for a one-time job, hire a core drill in Dublin from A-Z Hire.

Step-by-Step: How to Drill a Wall Vent

1. Plan and Scan the Wall

Use a wall scanner to locate studs, electrical cables, or pipes. Choose a location that allows for straight ducting and complies with ventilation regulations. For kitchen extractor vents, follow the recommended clearance from the hob or cooker.

2. Mark the Hole

Use the duct sleeve or internal flange to mark your circle. Identify the centre and use a spirit level to confirm horizontal alignment. Always drill from inside the house at a slight downward angle to prevent rainwater entering the duct.

3. Drill a Pilot Hole

With your SDS drill and long masonry bit, drill a 10–12 mm pilot hole from the inside wall to the outside. This hole guides the core drill and helps you align both sides if you plan to drill from each end.

4. Drill the Main Vent Hole

Attach the diamond core bit to your core drill. Set the drill to rotary-only mode (no hammer). Start from the inside, using your pilot hole for alignment. Drill slowly and steadily — do not force the tool.

For thick or cavity walls, consider drilling halfway from each side to avoid breaking the external brickwork.

5. Clean the Hole and Fit the Duct

Vacuum or brush out the hole. Insert the duct sleeve and trim it to length if needed. Seal around the edges using weatherproof silicone or expanding foam to ensure an airtight fit and prevent water ingress.

6. Fit the Internal and External Vent Covers

  • Attach the external grille with screws and wall plugs if needed.

  • Install the internal flange, vent fan, or damper.

  • Test the system for unrestricted airflow.

Safety Tips Before You Drill

  • Always scan walls to check for cables or plumbing.

  • Wear protective equipment: mask, goggles, gloves, and hearing protection.

  • Use proper ladders or scaffolding for higher locations.

  • Work methodically — a clean hole ensures better results and easier finishing.

Still unsure which bit or drill to use? Visit A-Z Hire Dublin for guidance and tool hire advice.

Why Doing It Right Makes a Difference

Drilling a wall vent the correct way avoids issues like air leaks, poor extraction, and water ingress. A properly installed wall vent:

  • Improves air quality and moisture control

  • Ensures compliance with building standards

  • Looks professional inside and out

  • Saves time and money in the long run

Hiring from a local tool hire company like A-Z Hire also reduces cost and avoids the hassle of buying and storing specialist tools.