Chimney Repair

Chimney Repair

The bricklayer in the video above is very good at what he does -just so you know.   Enjoy the video -of an artist at work applying mortar into the joints that were previously ground out.  He then ‘strikes’ the joints with a ‘jointer’ to finish the task.  Please hold the applause until his work is complete.  Below (on this page) is another video explaining tuckpointing and brick repair -on a wall, but the same principles apply to chimney repair.

Tuckpointing (or, Tuck Pointing) has historical significance in England but for all practical purposes, in the U.S. today, tuckpointing is the term used for repairing / restoring the loose mortar in a brick structure.  The term is interchangeable with repointing brickwork or ‘pointing’ -as in ‘pointing up’ a chimney or other brick structure (like a wall, for example).  Restoration of the mortar re-establishes the structural integrity of the wall or chimney and if done correctly, will preclude the infiltration of water and will add decades of life to an otherwise doomed structure.

From the time we are little kids listening to the tale of the Three Little Pigs, we get the notion that brick structures are impermeable.  Whereas bricks last much longer than houses made of sticks or straw -everything needs maintenance -including bricks and mortar.  Brick structures can last decades or even generations without much attention.  Eventually the side of the chimney or structure most affected by weather will require some ‘pointing up’.  If that maintenance is deferred, a slow downward spiral begins, spinning more rapidly with each passing year as water infiltration ever increases and damage increases exponentially.  Even mountains crumble into the sea.  In the Big Picture, we don’t own brick homes (although we pay dearly for them) -we are only the caretakers of them for the next generation who will inherit them.

A mortar joint is the ‘bed’ of mortar the brick is laid upon.  The ‘head’ joint is the vertical joint at each end of every brick (sometimes called a perp -for perpendicular).  Over time, from exposure to the elements, the original mortar joints may become cracked and loose, especially on the side facing the prevailing weather patterns.  Cracked mortar joints allow the infiltration of water, as do broken or cracked bricks.  Water infiltration is bad enough, but in winter it freezes and expands, causing damage and compromising the integrity of the brick structure.

Over time, the bricks in a chimney may become loose -typically from the top down.  Once that happens, tuckpointing is not an option.  The chimney must be torn down -at least to where the brick structure is solid.  That point is sometimes at the roof line.

When a brick becomes cracked or spalled it must be replaced.  A good mechanic can remove a cracked brick using a hammer and chisel without damaging the adjacent bricks.

Tuckpointing is not merely smearing mortar over a cracked mortar joint.  Done properly, the entire portion of the compromised mortar joint is cut back (partially or wholly removed) using a hand chisel or power grinder.  The joint should be cut back 1/2″ to 3/4″ or completely removed, if loose.  Once the bad mortar has been removed, the joints are cleaned of particles and dust.  New mortar is then ‘tucked’ into the joint using a trowel and ‘tuck pointer’ (not a pastry bag).  The mason then ‘strikes’ the joint (using a hand tool called a jointer) or ‘rakes out’ the joint, depending upon the original design.  (A  jointer is a steel hand tool that gives the joint a concave appearance and the rake removes about a quarter inch to recess the mortar).

When replacing brick, matching the old brick is sometimes a challenge and sometimes not possible.  Some of the new so-called ‘blends’ of brick are made to resemble the older brickwork that has been weathered over the decades.  So, look around -you may find something really close.

Matching the existing mortar sometimes requires adding dye to the new mortar.  Be aware that the new mortar dries a lighter shade than what you see before it sets up.  If color matching is critical, it is best to test some mortar on a couple of sample bricks.

Be sure to wear your PPE (Personal Protective Equipment) -eye and face protection and gloves when using a hammer and chisel and/or electric grinding wheels.  When using a grinder, a dust mask is also recommended.

Here are a few additional resources for information:

Tuckpointing Tools

Repointing Brickwork

Spalled Brickwork

Brick Mortar

Brick Trowel

One thought on “Chimney Repair”

  1. Thank you for the sensible critique. Me and my neighbor were just preparing to do some research on this. We got a grab a book from our area library but I think I learned more from this post. I am very glad to see such great information being shared freely out there.

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