Maintaining your chimney: a handy how to

Chimneys and vents break the surface of your roof, so they're always potential trouble spots. Make regular inspections of your roof surface, chimney stacks and vents so that any faults can be fixed before any significant damage occurs. Here are a few handy tips.

  • Only work on a roof if you feel competent; otherwise call in an expert.
  • When inspecting chimney stacks, first check the pots, then make sure the mortar holding them in place is intact. Next, inspect brickwork and pointing, making note of damaged bricks and missing mortar.
  • Consider capping unused flues to keep dirt and debris from falling through them.
  • Lead or aluminium flashing makes the joint between the chimney stack and the roof surface waterproof. Make sure the upper edge is held securely in the mortar and the lower edges lie flat on the roof; otherwise rain can leak into the roof space.
  • The internal angle where two roof slopes meet is usually lined with a metal tray secured to wooden boards. Keep this tray clear of wind-blown debris so it doesn't overflow and soak the wood. Check the tray regularly for corrosion holes, too – any you find can be waterproofed temporarily with self-adhesive flashing tape.
  • Check that all your roof vents are capped, otherwise unwanted pests, and all sorts of airborne debris could get in. Heavy-duty flywire secured with a hose clamp can be an effective substitute when a purpose-made cover is unavailable.

A common repair job on the roof that's related to chimneys is fitting new vent flashing. Here's a handy three step guide.

Maintaining your chimney: a handy how to

What you will need

  • Tape measure
  • Utility knife
  • New vent flashing
  • Pencil
  • Roofing sealant

Before you begin

  • First remove any old flashing that remains around the vent you'll be working with.
  • Scrape off as much of the old sealant as possible.

1. Prepare the vent

  • Measure the diameter of the vent pipe and, using a sharp utility knife, cut a matching hole in the rubber of your new vent flashing.

2. Slide it on to size it up

  • Slip the new flashing over the vent.
  • If necessary, trim the neck of the rubber sleeve so that it fits your vent pipe snugly.
  • Push the flashing down the vent pipe until it touches the roof, then carefully mould the base to fit the contours of your roofing.

3. Seal it in

  • Mark the position of your new flashing's base on the roof and then pull the flashing back up the vent pipe.
  • Lay a bed of sealant on the roof and then press the base of the flashing into it.
  • Apply more sealant around the base and top of the flashing.

Keep these tips and handy how to in mind to keep your chimneys and vents clear and in working order.

The material on this website is provided for entertainment, informational and educational purposes only and should never act as a substitute to the advice of an applicable professional. Use of this website is subject to our terms of use and privacy policy.
Close menu