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How Much Efflorescence is Too Much?


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I see this often on chimneys in our region.

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From the outside, the brick and mortar is reasonbly OK and it's flashed OK through the roof.

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The roof is new though, and I suspect the old roof had bad, leaky flashing. Also, I'm thinking the flue was uncapped - now it has a weather cap. The mortar crown is cracked and been sealed with a some sort of goop - mortar crowns are typically cracked also.

Point being, I suspect the water typically comes through the flue itself (when it was uncovered), the mortar crown, and seeping through the mortar.

Is this a problem or is just wear and tear?

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Efflorescence is associated with cementitious materials such as brick and mortar. Water moving from behind and out of cementitious materials results in the deposit of salts on the outer face of the wall as the water evaporates.

As far as I know, it isn't an issue, other than to evidence intruding moisture.

Marc

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It needs a new crown.

That much efflorescence means that the stack is taking on a lot of water. The goop that they've sealed that side crack with and the perimeter of the crown isn't going to stop water permeating that stack and it's eventually going to weaken the bond at those top courses of brick. I'd recommend they get a reputable mason to knock that wash cap off there and install a decent reinforced crown complete with expansion joint and built-in drip edge that will ensure water never drains into that stack again.

When you said steel pre-fabricated, were you referring to the heavy steel inserts with the masonry stack built around them and the intake vents below and to the side with the three large heat tubes through the throat above the box or are you referring to a zero-clearance type like someone was asking about last week?

ONE TEAM - ONE FIGHT!!!

Mike

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It needs a new crown.

When you said steel pre-fabricated, were you referring to the heavy steel inserts with the masonry stack built around them and the intake vents below and to the side with the three large heat tubes through the throat above the box or are you referring to a zero-clearance type like someone was asking about last week?

ONE TEAM - ONE FIGHT!!!

Mike

It's an old Fireplace Xtrordinair. I believe it's the style you were describing first.

I'm familiar with the heat tube system but can't think of the name of it right now.

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