waterproofing chinmey on cabin


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Old 11-17-08, 01:42 PM
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waterproofing chinmey on cabin

I asked my chimney sweep to take a look at the flashing around my chimney, he said it all looked fine, but suggested that the water that is leaking in around the chimney is likely coming in through the pourus brick itself. he suggested sealing it with a brush on or spray on product to seal the brick. I've searched online for such products and havent been able to find much other than this stuff called DEFY Water Repellent for Brick. they have a water based and a solvent based product for the same thing. it is a modified siloxane based product for sealing most masonry and concrete pores.

Is this the right kind of product to use on my chimney? I have an A frame cabin and the chimney is in the center of the building so it only penetrates the building near the peak. It is hard to get up there even by ladder. does anyone have experience with this type of product or can you reccomend any other product? thanks.
 
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Old 11-17-08, 07:49 PM
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How old is the chimney? Is there a cap on it? Brick needs to breathe, so sealing it may not be the best idea. That's according to a chimeny guy I know. Look a little more closely for the leak.
 
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Old 11-17-08, 09:40 PM
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the building was built in 1962. pretty sure the chimney is that old as well. not sure what repairs have been done over the years. the flashing etc around the chimney all look very good.

This product claims it still allows the brick to breath, while still repelling water.
 
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Old 11-18-08, 06:08 AM
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Is there a cap on the chimney and where do you see the water leak on the inside? The product your considering is only a temporary fix, if it's a fix at all. How is the cement between the brick? I still think you are missing something. Have another look.
 
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Old 11-18-08, 06:20 AM
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there is a cap on the chimney and the mortar all looks quite good. no visible deterioration at all. The brick inside just gets wet in a steady rain storm and then the tongue and groove 2x6 roof planks wick the moisture off the brick and it runs along the wood planks.
 
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Old 11-18-08, 04:35 PM
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If everything looks as good as you say, I don't see how the water is passing through the brick itself. Try the water repellent if you want but I still think there is something missing.

You said it was hard to climb to the top. Use a pair of binoculars to look from the ground.
 
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Old 11-18-08, 05:12 PM
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Be aware if the proper sealer for exterior brick is not selected, sealing can do more harm than good. Avoid surface sealers that will seal pores in brick. Water vapor must pass through brick. Surface sealing can cause brick to spall. A penetrating siloxane based sealer will prevent water from entering brick but allow vapor emissions.

You can check at local hardware and building supply stores for siloxane based sealers. You can also Google for them.

You say you have a chimney cap, but you make no mention of the condition of the crown. If crown is cracked or poorly constructed, it can allow moisture penetration behind brick.
 
 

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