[jgold723]

The backstory: We recently put an addition on the side of the house which wraps around a chimney that was formerly outside the house. Following a pretty severe rainstorm last night we discovered water leaking down the side of the chimney (inside the addition). The chimney is well flashed and I have confidence that the contractor did the job properly.

We believe the water is coming from the brick joints above the roof, many of which are cracked.

So, the chimney needs repointing. Easy, except it's winter, in Maine too cold to do the work now without a lot of extra labor (setting up a tent and heat source). And at any rate, I can't find a contractor who will get here in less than 8 months anyway.

So... how do I get through the winter? Is there any kind of temporary fix that I can do to fill the joint cracks that isn't temperature dependent? I've been told that silicone is a bad idea because it will make it more difficult to properly repoint later.

One mason suggested wrapping a tarp around the chimney and securing it with cinch straps. A possibility, but not a pretty one.

 

[chandler48]

Can you post pictures so we can have a better idea of what was built and how it was built.

 

[jgold723]

Of course! The overall shows the addition (garage and breezeway) to the left of the chimney. the close up shows the chimney and flashing. If you zoom in, you can see the cracked joints. I'm thinking I may just get some quick-setting concrete patch and stuff that in the gaps to tide me over until the job can be done properly.

 

[Racinmason]

It can be pretty tough finding out where water is coming in. Usually when a chimney lets water in through faulty joints, the water stays inside the chimney.
I assume the brick chimney is visible down inside the room addition? It would be improbably for the water that entered the chimney above the roof to let that water back out down below where it's exposed. If it wasn't properly flashed, I could see water running down the chimney into the new room.
I wouldn't recommend a homeowner start filing faulty mortar joints, especially with concrete patch. Any mortar or concrete you get on the face of those brick will stain them, possibly forever. Your mason will have a much harder job when he finally gets up there. At least silicone can be cut out later, if you decide to go that route, and won't kill the brick.

You need to find out where the water is coming from first. Use a garden hose on the brick might help to isolate the leak.

Any reason why the outside brick are all turned dark, is that from the smoke? Those caps in that fashion are notorious for letting water enter the chimney.

I would cover it with a tarp like your mason said until he can fix it.
Do you use this chimney?

 

[jgold723]

We do use it. There are two flues, one on the left for the boiler, one on the right for the fireplace. I would assume the staining is from the fireplace over the years. Both flues are lined -- the boiler flue has a stainless steel liner and the fireplace is lined with the original clay tile. Both liners are in good condition.

 

[chandler48]

The only thing I see that could be a problem is there is no crickets on the upper side of the chimney to direct the water away from the flat edge (a water capturing edge).

 

[FM3]

Following a pretty severe rainstorm last night we discovered water leaking down the side of the chimney (inside the addition).

So, the chimney needs repointing. Easy, except it's winter, in Maine

One idea is if it can't be done easily enough now is wait till spring since winter has more snow than rain so it perhaps won't find its way into the joints as much.

I wouldn't use concrete patch on something that isn't concrete. If you're going to go up on the roof and do that, then just use Type N mortar instead to do it right. Check your weather. You might have a 40-degree day or two coming yet and could get at least the worst joints done then.

 

[stuart44]

Bing Videos Bing Videos Bing Videos Bing Videos Bing Videos Bing Videos Bing Videos Bing Videos Bing Videos Bing Videos Bing Videos Bing Videos Bing Videos Bing Videos
Chimney stacks can allow moisture through the brickwork, so nowadays lead trays are always put in.

 

[Racinmason]

Apply Siloxane based masonry/concrete waterproofing to the brick and concrete cap and no water will get in. Have the masons tool the joints with a metal rod or round jointer will help the joints become more waterproof.

 

[SeniorSitizen]

Rain water through the brick is BS .

If rain water going through the brick is the problem every brick chimney on earth would leak .
Look for another problem .

 

[Racinmason]

Rain water through the brick is BS .

If rain water going through the brick is the problem every brick chimney on earth would leak .
Look for another problem .

You're correct, to a point. But there are huge differences in brick and some are extremely porous. I've seen Chicago Adobe brick become a huge problem with moisture....drop one brick in a gallon bucket of water and that one brick soaked up the whole gallon.
I'll bet 25% of brick chimneys let some moisture in, and some of that is the method the masons finished the joints. About 16% of a brick wall is actually mortar. Even the guy mixing the mortar can make a difference, too much sand and that mortar looses strength and becomes less waterproof.

 

[jgold723]

Thanks everyone for the responses. Based on this and some other discussions, I plan to wrap the chimney in movers cling wrap to get me through the winter and then repoint/waterproof in the spring. Yeah, gonna look a little funky to the neighbors, but I'll just tell them it's a Christmas present for Santa...

 

[chandler48]

If it turns out NOT to be the brick per se, you won't only look goofy to the neighbors, you will have the leaking continue. I still say you need crickets to divert the water around the chimney.

 

[Racinmason]

If it turns out NOT to be the brick per se, you won't only look goofy to the neighbors, you will have the leaking continue. I still say you need crickets to divert the water around the chimney.

Sometimes there are "crickets" on here
All he needs is half of a cricket on the high side, an elevated roof panel against the house to divert the water.
I'll bet $5 is a flashing leak and not the brick.

 

[chandler48]

I was basing it on the second picture in post #3. I didn't see any diversion method. It looks flashed well, but the chimney goes into the cave created by the overhang, so who knows what flashing was done way back up under there, if any.

 

[Racinmason]

I was basing it on the second picture in post #3. I didn't see any diversion method. It looks flashed well, but the chimney goes into the cave created by the overhang, so who knows what flashing was done way back up under there, if any.

It would be nice to have a photo of that area also.

OP....was the water below concentrated in one certain area or was it over all of the brick?

 

[jgold723]

So, some answers...
1) Although it's not visible in the photo, there is a slight slope built in on the high side of the chimney along the lines suggested by racinmason. Not a formal cricket, per se, but it should direct water away from the chimney (although perhaps insufficiently in a heavy downpour like the one we experienced?)

2) The wrapping is a test to see if indeed this is a brick/mortar issue or a roofing structure issue. The contractor has promised to fix it if the wrapping doesn't solve the problem. Of course, this being Maine, we may not get a real test for several months.

3) The water was actually most visible on the wide side of the chimney, the side which the roof slopes beside (does that make sense?). On the narrow, uphill side of the chimney, there was very little moisture.

 

[stuart44]

						You're correct, to a point. But there are huge differences in brick and some are extremely porous. I've seen Chicago Adobe brick become a huge problem with moisture....drop one brick in a gallon bucket of water and that one brick soaked up the whole gallon. I'll bet 25% of brick chimneys let some moisture in, and some of that is the method the masons finished the joints. About 16% of a brick wall is actually mortar. Even the guy mixing the mortar can make a difference, too much sand and that mortar looses strength and becomes less waterproof. It's probably more than 25%. When people had their fires going all day, the heat keep them dry. Nowadays with central heating the damp issues are more common, especially with loft conversions. The Building Research Establishment here did some tests on cavity walls a few years ago, with different walls, and found that poorly built brickwork allowed water through the head joints after 20 minutes from a sprinkler. It ran down on to the snots, bounced off the wall ties and against the inner blockwork.

 

[SeniorSitizen]

						The Building Research Establishment here did some tests on cavity walls a few years ago, with different walls, and found that poorly built brickwork allowed water through the head joints after 20 minutes from a sprinkler.

To me this reads poor construction policy rather than a brick acting as a sponge .

 

[stuart44]

Most of the moisture comes through the head joints. Although in theory they should be full, they are often only half filled. Also in time the joints weather back and become less weather proof. Bricks vary a lot in their porosity, but even on solid 9 inch house walls the soft ones perform well as the water is absorbed evenly over the whole wall, and then evaporates back out again before it gets inside. It's normally only in the coastal areas with prolonged driving rain that the plaster inside gets damp. That's where the cavity walls were first used in the late 1800's.