Expert: Randy Brooks - 1/20/2008

Question
About 3 years ago, we had a gas fireplace insert installed into our existing brick wood-burning fireplace. All was well until this fall, when we had our first really heavy rainfall with high winds of the season, that I noticed rainwater dripping onto the top of our gas fireplace insert. This continued to only happen during days with heavy rainfall.  I started to catch it in bowls since it was rusting my insert.  I collected about 1 cup every two hours of rain.  We live in the Pacific Northwest where is rains continually throughout the winter - this is not a problem.  It's just a problem when the rain is heavy, and even worse when coupled with any kind of wind.  We usually get storms like this only a couple of times each month in the winter.

We figured it was the chimney cap failing (cracked or dislodged).  We have a brick/mortar cap that is closed off on two sides and open on two sides.  Another possibility I considered was that the insert tube that pops out of the top of the chimney somehow was now collecting the rainwater and allowing it to fall down into the chimney (whereas in the past years it was somehow preventing it from getting inside the chimney).

We have had two quotes for fixing the leak from experienced and qualified chimney 'leak experts'. One told me my Chimney's mortor was cracked and had holes all over it and it needed to be replaced (at the bargain price of $4,300). I asked if he could do a repair - he said their company does not do repointing because he cannot guarantee it because it always fails. Ummm...okay, I thought people repointed all the time? Don't people with brick houses have to repoint?

Expert #2 told me basically the same thing, but said he could repair it by repointing the entire thing and replacing the chimney cap and gas fireplace top, etc. His bargain price was $1,800.  This repair is closer to what we think needs to be done, but it's still overkill, in my opinion.

We decided to try to diagnose the leak ourselves to arm us with more info (thank you, internet!).  We went on the roof to look at the chimney itself, there were only about 7-8 keyhole size holes in the mortor - not too bad.  We also did a water test starting from the bottom of the chimney from roof/flashing and ending at the top where the cap is.  We tried to similate hard rainfall coming at it diagonally.  When similating the heavy rainfall, we only got a leak through the top of the chimney (in the same spots where it normally leaks, I might add).  It was doing exactly what I thought it had been doing.

In order to get the chimney to leak as the result of the mortar cracks, we had to spray water with lots of pressure right into the holes for over 5 mins.   The leak was not that bad and in a different spot near the rear of the chimney, mostly on the bricks - not right on top of the insert.  Looks like the chimney cap area is the true culprit here.

So, my question now is what is the simplest way to fix this?  We are selling our house in the summer and our goal is to have our chimney look the same (since we have another on the other side of the house that is a twin), but just be leak-proof.  Our goal is to also do it as cheaply as possible, but by a hired professional if need-be.

Can those cracks just be repointed/patched (as long as the old mortor is scraped away 1 or 2 cm)?  Seems like repointing the whole chimney would be overkill - and obviously more costly.

Can we get a better water-catching/draining system at the top of the chimney installed?  Keep in mind, we have a brick chimney cap that we'd like to keep, so I am curious if a metal chase cap can be installed inside the brick cap and overtop of the gas insert?

I think our biggest challenge is that most of these 'experts' won't fix just what you want them to (or what you feel is necessary), because they cannot/won't guarantee it, and therefore if they cannot stand behind it, they won't do it.  So we're wondering if there's something we can do ourselves (short of tarping up the top of the chimney!).

Any advice would be much appreciated.

Thanks for reading!
Paula


Answer
Paula,

There are a number areas that water will typically enter your system. Water can weep or absorb right through your chimney crown or cover as it sounds. This can easily be repaired by a chimney professional. The second potential area is the exterior, not so much the 7 or 8 key hole thing, but again the surface becomes soaked over extended periods of rain fall, Again said chimney pro is your choice. A third possibility is of course your flashing, I'm no roofer so cant offer any suggestions there.

I will refer you to the "Chimney Safety Institute of America's" web site to find a qualified service provider to help you. You will most likely be required to invest in an inspection but this be worth that investment. WWW.csia.org, is the place to start. I never recommend you attempt to solve this issue yourself, as a real pro has the proper equipment and knowledge to get to the bottom of your problem. Best of luck.