How to Fix a Chimney That Is Pulling Away From the House

When the chimney on your house begins to pull away from the roof or walls, it can cause a multitude of problems.

A properly functioning chimney leads smoke out of your home.A properly functioning chimney leads smoke out of your home.
These problems range from leaks that can drip into the house or weaken the structure of the roof to the chimney crumbling away from the foundation entirely. If the chimney is pulling away from your house, you should take steps to repair the issue as soon as you notice it. With the proper repair, you may be able to return your chimney to working condition.

Check the mortar around the base of the chimney if the chimney flashing is pulling away from the roof. Though chimney flashing at the base of a roof chimney often pulls away due to the presence of moisture, it may also pull away due to cracks in the chimney mortar.

Remove any mortar that is cracked or crumbling in the chimney with a grout saw. After scraping out any damaged mortar, continue removing good mortar to a depth of 3/4-inch.

Spray the wall with a hose to clean out the mortar bits. Allow the wall to dry 24 hours before applying new mortar.

Mix a batch of mortar according to the manufacturer's instructions until it is paste-like and sticks to the trowel. Apply the mortar to the gaps in the brick until it sits evenly with the brick. Allow the mortar to dry to the touch and brush off the wall.

Place a tarp over the repaired chimney. Lift the tarp once every day and spray the mortar lightly with water. Leave the tarp for 72 hours before removing it.

Hammer the flashing so that it sits flat against the roof if the metal has warped. Apply waterproof sealant around the edges of the flashing with a caulking gun and allow the sealant to dry 72 hours to repair the flashing seal. Alternately, apply a flashing seal to the base of the chimney around the flashing, which applies with an adhesive backing and also creates a watertight seal.

Things You Will Need

  • Grout saw
  • Garden hose
  • Mortar
  • Bucket
  • Trowel
  • Cleaning brush
  • Tarp
  • Waterproof sealant
  • Paintbrush
  • Flashing seal

Tip

  • If you have a full-length chimney that is pulling away from the side of the house, this can be a sign of serious structural issues with the foundation. The experts at This Old House advise that a leaning chimney is not something a homeowner should attempt to tackle alone. The house should be inspected for structural damage and the chimney should be fixed by a certified mason.

About the Author

Alexis Lawrence is a freelance writer, filmmaker and photographer with extensive experience in digital video, book publishing and graphic design. An avid traveler, Lawrence has visited at least 10 cities on each inhabitable continent. She has attended several universities and holds a Bachelor of Science in English.