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Chimney Cap

Westchester's picture

Hello -

 

Please - need some advice - 

The local builder stated that I would be better off tarring the cement top cap of my chimney.

Is this a normal procedure -  I'm thinking the sun all day long on the tar will effect any usefulness of the sealer properties.

 

Thanks for the help,

 

SA

The local builder stated that (post #188671, reply #1 of 20)

The local builder stated that I would be better off tarring the cement top cap of my chimney.

Bwahahaha.

 

You'd be better off tar & feathering that nitwit.

 

There are some coatings that will work on chimney crowns (Geocel 2315 is one that I've used with success), but it will be a maintenance item. A better option would be a non-rusting metal cover (copper or stainless steel).

Yessir......... (post #188671, reply #2 of 20)

nothing worse than looking up at a roof or chimney and seeing a bunch of black roof goop.

A Great Place for Information, Comraderie, and a Sucker Punch.

Remodeling Contractor just outside the Glass City.


http://www.quittintime.com/

 


asphalt? (post #188671, reply #3 of 20)

Ugly, maybe I could live with, but  if this is a chimney for something that burns wood then it just strikes me as being a poor idea to top it off with stuff like they make gasoline out of.  But I may be just too ol' timey.

.

If you had a chimney fire I suppose it would be icing on the (post #188671, reply #4 of 20)

cake.

And ugly is subjective.

Me?  I'd just be plain disgusted with that water vapor inhibitive leak cause coverer.

The only place for that stuff is under a shingle or the bottom of a deck post.

A Great Place for Information, Comraderie, and a Sucker Punch.

Remodeling Contractor just outside the Glass City.


http://www.quittintime.com/

 


The only place for that stuff (post #188671, reply #7 of 20)

The only place for that stuff is under a shingle or the bottom of a deck post.

I don't even know about that. In 20+ years of roofing, I have yet to buy my 1st bucket of tar. I have bought lots of "Gojo" to get it off of things it shouldn't have been on.

Evry one uf mah sheds wud (post #188671, reply #17 of 20)

Evry one uf mah sheds wud leak ifin it aint fer tar. 

How else ya gonna patch up the screw holes and water inlet holes in the flattened old wash machine cabinets? 

 

 

I don't see that it's (post #188671, reply #5 of 20)

I don't see that it's necessarily a bad idea.  You want the cap to be reasonably waterproof, to prevent frost damage and the slow deterioration of the mortar.  And if the fireplace is used much the area is likely to be sooty already.  Plus you can't generally see the top of the cap from the ground.

The stuff wouldn't be a fire risk, unless it was really fresh, runny stuff with lots of volatiles, or unless you got the temperature up to about 350 degrees.


Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville

I don't see that it's (post #188671, reply #6 of 20)

I don't see that it's necessarily a bad idea.

But that doesn't make it a good idea by default. It will stop the problem temporarily, but probably make it worse in the long run. When tar dries (which it will do rapidly in the sun on top of a chimney), it cracks and creates fish mouths which admit and trap more water. Then, one has to clean the tar off of the masonry before applying a proper fix. The fire hazard angle doesn't concern me and it's not likely there's much "soot" on the top of the chimney unless there are significant draft problems. The smoke exits the flue and keeps rising. Any ash that might be carried in it that could possibly land on the chimney crown will wash away in the next rain.

By your reasoning, smearing tar all over your car would make the paint last longer. I'll send you a bucket if you'll post pictures.

 

Helpful Comments (post #188671, reply #8 of 20)

Great comments from all  - I'm thankful you're out there for us DIY er's   -

Here's what I think I'll try :  I purchased a gallon of Professional Water Sealant - contains Silicone Rubber - made in Wichita, KS.

Received good reviews down at my local Stone Suppy shop.  After a week of dry weather - I will coat the bricks and the top cap with this stuff and see how that works out.

When I called the Co. (Professional)   the owner himself answered the phone and spent time with me answering a bunch of questions regarding - application, warrantee, recoating, etc.  seem like good people - owners name is Ken. 

 

Thanks,

SA

Don't coat the sides of the (post #188671, reply #9 of 20)

Don't coat the sides of the chimney, just the horizontal surfaces.


Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville

Surfaces (post #188671, reply #10 of 20)

Dan H

 

Please explain ?

I was going to do the brick as well ?

 

SA

Well, you don't say where you (post #188671, reply #11 of 20)

Well, you don't say where you live, but any place where it freezes (even occasionally), the sealant will hold moisture in the brick, causing it to spall when it freezes.

(This is the main reason why you want the top to be reasonably waterproof -- to reduce the amount of moisture working its way down into the masonry below.)


Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville

New York (post #188671, reply #12 of 20)

Westchester County - many freezing months during the winter.

If I seal the brick thoroughly - doesn't  that  prevent moisture from entering the porous conditions of brick and mortar -

The pointing / joints are good - did it last year - 

Trying to help it last since I do get an area or two every year that re-crack. 

Don't want to rebuild the Chimneyy from the roof line up - too expensive -

Your thoughts are appreciated - 

 

Thanks,

SA

The moisture enters from the (post #188671, reply #13 of 20)

The moisture enters from the top.


Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville

Moisture (post #188671, reply #14 of 20)

Dan

If I seal the top cement cap  and the vertical bricks as well -  you don't believe that approach works ? 

I'm  thinking if all is sealed well - with  2 coats of  Professional Water Sealant - following many warm dry days before application,  and there was a little moisture trapped behind the brick - wouldn't and couldn't the moisture escape to the flu side ? 

Over the years the unsealed brick has always developed cracks and loose mortar - now that it's been repointed - don't I do everything possible to prevent rain from wearing on the porous materials ?

 

Thanks for the continued comments -

SA

Dunno -- you can wait for (post #188671, reply #15 of 20)

Dunno -- you can wait for others to weigh in, but I'd be reluctant to seal the sides.


Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville

common (post #188671, reply #16 of 20)

maintenance on old brick  chimnies would be to inspect:  then

fix  or replace the concrete cap  ( special masonry caulks )

fix the  pointing  or repoint the  whole chimney

fix or replace the flashings

seal all the brick  with a common masonry sealer

some brick is more  absorbent than  others..

if you have a continual wet period , the brick ( unsealed ) will absorb more water than it can hold

at which point  it will  start leaking into the structure  ( unless the chiney is thru-flashed , which is common with stone chimneys but not with brick chimneys ).. just as a sponge can absorb and hold a certain amount of water, once it reaches saturation it becomes subject to t the law of gravity.. then water seeks the lowest level

so .. hard fired (glazed ) brick   and  good mortar will not  let in much water... but other brick and  weathered mortar joint will..

 thus  you apply a sealer.. most masons use a water based spray on solution..

 as for the top.. Grant 's solution of a full metal cap  ( copper, lead-coat, or SS ..... not galvanized )  is an excellent solution for long life... and can also become part of  the anti-squirrel/anti-raccoon  system

but  almost all brick chimeys benefit from a sealer on the sides... most brick is just not water-proof

Mike Smith Rhode Island : Design / Build / Repair / Restore

              www.mfsmithbuilder.com

Thru-Flashing (post #188671, reply #18 of 20)

Thanks Mike and all for the advise -

 

Mike when you say thru-flashed I'm wondering if this is what mine is ?  On the sides where the cooper flashing meets the brick - the copper is bent over and entters the brick in a seam 1/2 inch  deep-

During the last pointing - the mason repaired the flashng with new mortar at those seams as best as possible followed by roof cement over the top of the staircase like pattern -

The roof cement  on the flashing seam isn't great looking but the waterproofing was important - he did it well - it's done neatly anyway.

A perfect flashing job would have meant new cooper and tearing back the roof shingles - a cost I wasn't able to pay at the time.

The mason charged $ 400.00 -it was a days work with two guys - seemed very reasonable -  he did almost every joint and changed a few bricks. 

I'm thinking sealer and protecting the top cap is the way to go  now -

Summary comments are greatly appreciated -

 

Thanks,

SA

 

 

 

 

 

................................................................ (post #188671, reply #19 of 20)

followed by roof cement over the top of the staircase like pattern

 

ugh.

A Great Place for Information, Comraderie, and a Sucker Punch.

Remodeling Contractor just outside the Glass City.


http://www.quittintime.com/

 


Through-flashing is installed (post #188671, reply #20 of 20)

Through-flashing is installed as the chimney is built/re-built. It extends through the brick/stone to the flue liner. Any water that penetrates the crown or veneer is forced back to the surface before it can penetrate the building envelope, which is a problem with especially pourous brick and stone. A proper crown/cap is still necessary to reduce the chance of freeze damage where freeze/thaw cycles occur.


If the flashing is face applied (as your's is), 1" extension back into the brick is the accepted minimum here. 1/2" would  not be functional. A hard rain will saturate the brick much deeper than 1/2".