Most homeowners never think about
masonry chimney maintenance beyond
the occasional flue cleaning. But ignoring your chimney can
cost you big-time. A cracked chimney
crown or spalling bricks can easily cost
$1,000 to repair. And, if left untreated, the
damage can accelerate quickly, and cost
you upward of $3,000.
It doesn't have to be that way. By
simply sealing the bricks and the crown
and adding a chimney cap, you'll greatly
extend your chimney's life. The materials
cost less than $300, and you can complete
all three procedures in just a few
hours. You'd pay a pro about $1,000 to do
all three, so the savings is huge.
You'll have to climb up on your roof
twice (once to measure the flue liner to
order the correct chimney cap and once
to perform the procedures). And, you
must be able to safely reach the chimney
crown from your roof. If you can't reach
the chimney crown, have a very steep roof pitch or aren't comfortable working on your roof, call a pro. If you decide you can handle the heights, make sure you wear a safety harness.
Professional chimney sweeps.
Meet the Pros
14 years. He
and his son,
chimney sweeps. Together, this father/son team inspects, cleans and repairs
chimneys in the Minneapolis-St. Paul
area. In addition to his chimney sweep
certifications, Jim holds a certificate in
forensic chimney fire analysis. In other
words, Jim understands how chimneys
work and fail. He’s a pro's pro.
crown sealer, $60
- Chimney water
- Garden pump
- Stainless steel
- Tarps, duct
Start at the chimney crown
Masonry chimneys are capped with a mortar
"crown" to prevent water from getting behind the
bricks and alongside the flue, and into the house.
Over time, normal expansion and contraction cycles
can cause cracks to form, as shown above. Sealing
the chimney crown with crown sealer, a flexible
elastomeric coating, is the best way to stop existing
cracks from spreading and prevent new ones.
Choose a clear or overcast day for the project
(no rain in the forecast for at least four hours).
Prepare the crown by cleaning it with a stiff poly or
nylon brush. Fill any large cracks with patching
cement or 100 percent silicone caulk (they'll cure
even after you apply the crown sealer).
Next, wrap duct tape all around the crown about
1/4 in. below the edge of the crown-to-brick seam.
Press the tape into the vertical brick joints. Then
tape around each flue liner 1 in. above the crown.
Lay canvas (not plastic) tarps around the base of
the chimney to protect the shingles from crown
Our chimney repair expert applies crown sealer
by hand so he can force it into cracks and get the
first coat done faster. If you choose that method,
just slip on a disposable glove and apply the sealer
(Photo 1). (One brand is Chimney RX Brushable
Crown Repair; sold by the gallon at saversystems.com)
Cover the entire crown and then smooth it with a
paintbrush (Photo 2). Wait until the sealer dries
tacky to the touch, then apply a second coat with a
brush. Clean up with water.
Seal the chimney bricks
Once the crown sealer feels dry to the touch (30 to
60 minutes), remove the duct tape but leave the
roof tarps in place. Then mask off any painted
chimney flashings before applying the water repellent.
Spray on the repellent (one brand is Chimney RX
Masonry Chimney Water Repellent; sold at saversystems.com) with a low-pressure, garden pump
sprayer (Photo 3).
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Finish it off with a chimney cap
A chimney cap keeps water and critters out of
your flue and extends flue life. Many codes require
a mesh cap, so check before buying. Chimney
expert Jim Smart recommends spending extra to
get a stainless steel cap because it will last much
longer than the galvanized type. One source for
stainless steel caps is efireplacestore.com
You'll need the outside dimensions of the flue
liner to get the right size cap for your chimney.
Then install it on the flue liner (Photo 4).