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Planejane (Planejane)
Intermediate Member
Username: Planejane

Post Number: 32
Registered: 12-2006
Posted on Sunday, March 14, 2010 - 12:04 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only) Ban Poster IP (Moderator/Admin only)

Wow, really nice website Mohawk!!!
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Planejane (Planejane)
Intermediate Member
Username: Planejane

Post Number: 31
Registered: 12-2006
Posted on Sunday, March 14, 2010 - 11:21 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only) Ban Poster IP (Moderator/Admin only)

Thanks Mohawk, that's great information! I'll use a grouter to take the mortar out that's too hard then I'll do what you said. I'll try to match it on my own where no one will see it and if I'm unsuccessful I'll buy a tub of the dry mix you recommended. You said to use the street dirt afterward. Do you mean after you use the restoration detergent a week later or while it's still wet after you put it in?
The house was built in 1929. This chimney (I have 3 chimneys) was built when the house was built. The other 2 were added later. It was an extremely well built house but improperly maintained over the years.
Jane
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Olde_mohawk_masonry__historic_restoration (Olde_mohawk_masonry__historic_restoration)
Senior Member
Username: Olde_mohawk_masonry__historic_restoration

Post Number: 135
Registered: 04-2007
Posted on Saturday, March 13, 2010 - 06:02 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only) Ban Poster IP (Moderator/Admin only)

Jane: You haven't told us the age of the chimney, so the proper recommendation IS a lime putty mortar with NO portland cement (which first appeared in the US in 1872.) Prior to that, the binder was hydrated lime or, in limited circumstances, natural cement (after 1820.)

ASTM very cleverly lists mortar types in the following manner from strongest to weakest, as follows:

MaSoN wOrK

Stronger implies higher compressive strength and ratio of portland to aggregate (sand.) Because your repointing work is largely aesthetic, and the integrity of the brick structure is not at issue, erring on the side of caution makes the most sense.

Mortar color is most determined by the aggregate. Indeed the use of play (or, "unwashed") sand is a trick that helps when repointing. I'm not a fan of adding pigments. Washing the repointed work with a weak restoration detergent a week or so later will take the shine off the tooled joints, expose the aggregate, and bring out the color you want. Afterward, I take some sand and dirt out of the gutter in the street and mix it in a cup with a little water. This is then sponged onto the new joints SLOWLY, and in layers, to gradually create patina.

If you're truly anal, you may want to spring for the $129 for a color match. They'll send you a small tub with enough dry mix to point up the chimney.
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Planejane (Planejane)
Member
Username: Planejane

Post Number: 30
Registered: 12-2006
Posted on Friday, March 12, 2010 - 11:29 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only) Ban Poster IP (Moderator/Admin only)

Correction; The mortar formula I should have used should probably be type "O" or "N" with washed rounded beach sand for children's sand boxes. And from further reading I should try yellow or buff pigment. Correct?
Jane
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Planejane (Planejane)
Member
Username: Planejane

Post Number: 29
Registered: 12-2006
Posted on Friday, March 12, 2010 - 09:51 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only) Ban Poster IP (Moderator/Admin only)

Thanks for your reply and the reference's. I read both. More info; The chimney is in good repair except the lady that owned the house before me had ivy growing all over it. It took 3 years for it all to come down after I cut the roots. There is a small amount of repair that needs to be done because of the ivy. So far the only place I used the mortar mix I told you about was on 1/2 the chimney flashing to hold it in place because the space was way to wide. Believe it or not, I did read up on what mortar to use, for this very reason. I found a good article in the June 2007 newsletter from Hudson Valley Vernacular Architecture. They gave 3 formulas, I think I just picked the wrong one. The other formula I should have picked (I think) was their Whitewash Recipe; One part hydrated lime & one part water? It just didn't sound like it would hold. I should have asked you guys first. Would this be a better formula?

As far as the color goes, I will do the matching that you recommended for a brick out door barbecue that needs to be rebuilt. After the roof is complete. But, for the chimney I have a very small amount to repair for now and want to try to match the color because I'm a total type A personality. No one will ever see it but me. I still want to try and match it. I thought about putting a little dirt in the mix but I'm sure you have better things to mix in for the small jobs you do to match the color a little better. Thanks again for sharing your trade secrets.
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John_chan (John_chan)
Senior Member
Username: John_chan

Post Number: 60
Registered: 08-2006
Posted on Tuesday, March 09, 2010 - 10:48 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only) Ban Poster IP (Moderator/Admin only)

Hi Jane,

Ward (Olde Mohawk) answered the question exactly how I would have answered it.

John
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Olde_mohawk_masonry__historic_restoration (Olde_mohawk_masonry__historic_restoration)
Senior Member
Username: Olde_mohawk_masonry__historic_restoration

Post Number: 132
Registered: 04-2007
Posted on Sunday, March 07, 2010 - 08:38 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only) Ban Poster IP (Moderator/Admin only)

Planejane, the mortar you just created is extremely "hard," meaning high portland content... as hard or harder than the pre-mix Quikrete puts out! IF it is harder than the bricks--and I reckon so--it will be the bricks that spall and pop, not the mortar. For $129 the US Heritage Group (www.USHeritage.com) in Chicago will create a hydrated lime putty mortar that will color match a sample that you supply.

Chimneys are a lot like slate roofs: Both are often the victims of butchers and those ill-informed. The WORST one can do to a chimney is repoint with too hard a mortar--it will often mean the end of the chimney. See:
http://www.info.wardhamilton.com/blog/bid/9755/All-Mortar-is-NOT-Created-Equal-H ow-the-Wrong-Repointing-Mortar-Will-HARM-Your-Masonry
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Old_school (Old_school)
Senior Member
Username: Old_school

Post Number: 412
Registered: 01-2009
Posted on Sunday, March 07, 2010 - 12:41 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only) Ban Poster IP (Moderator/Admin only)

Jane, IF you have a high efficiency device venting into your old chimney flue, you will have the same problem! The moisture will saturate the mortar and cause the problems you speak of. The best thing to do is to rebuild the chimney if it is falling apart; especially since you are installing a roof that will last another 70 years. You will want to make sure what the problem is before you fix it though. Re-read the posts before this one.
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Planejane (Planejane)
Member
Username: Planejane

Post Number: 26
Registered: 12-2006
Posted on Saturday, March 06, 2010 - 07:28 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only) Ban Poster IP (Moderator/Admin only)

John, On your post you talk about masonry restoration with lime mortars. I have an old house and I'm re-slating it. The chimney had a crack or 2 on the cap. I painted this thick layer of Geocel 2315 Leak Repair (about 6 layers) on it. I also had voids and crumbling of the mortar on the sides of the chimney between the bricks. I didn't buy ready mixed mortar I mixed my own. I used 1 part white Portland, 1/4 part Hydrated lime, 3 parts sand, & water. It seemed to have worked well but, I don't like the color match. Do you have any tips on matching the color of the old mortar and is this mixture a good one for chimneys?. My other question is; is that Geocel 2315 an okay fix. Please don't tell me I have to rebuild my chimney. Thanks for your reply, Jane
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Old_school (Old_school)
Senior Member
Username: Old_school

Post Number: 405
Registered: 01-2009
Posted on Monday, February 22, 2010 - 05:10 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only) Ban Poster IP (Moderator/Admin only)

Pinnacle, If that doesn't solve your problem, you can ask us again with a picture this time. I believe that has to be it though. good luck!
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Joe (Joe)
Moderator
Username: Joe

Post Number: 517
Registered: 07-2006
Posted on Monday, February 22, 2010 - 12:26 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only) Ban Poster IP (Moderator/Admin only)

Condensation inside a chimney. especially near the top where the flu gasses cool as they rise, is a common problem which will look like a leak. The difference between a leak and condensation is that a leak is usually localized in one place while condensation can show moisture on all four sides of the chimney. This problem tends to occur during cold weather. I have climbed up in roof spaces and seen ice on the outside of the chimney (inside the roof) on all four sides - condensation leaking out through porous bricks and mortar, seeping down the outside of the chimney and freezing, while the top part of the chimney where the flashing is is bone dry.

The solution is not on the roof or flashings - the chimney will need a liner.
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John_chan (John_chan)
Senior Member
Username: John_chan

Post Number: 56
Registered: 08-2006
Posted on Saturday, February 20, 2010 - 04:31 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only) Ban Poster IP (Moderator/Admin only)

Old School is right. Modern furnaces can cause an apparency of a leak.

I copied this from our website. The following are the most common reasons for leaks around chimneys:

* Flaws in the roofing material above or adjacent to the chimney
There may be a broken slate or tile nearby that is causing a leak. For tile roofs, the underlayment, which keeps water out, may be deteriorated.

* Flashing problems
The metal flashings around chimneys deteriorate and cause leaks. The old metal must be removed and replaced with soldered flashings.

* Poor joint between the masonry and counterflashing (the part of the flashing that is cut into the masonry joint)

* Condensation from a modern furnace
Newer, energy-efficient furnaces may cause problems with the chimneys in old houses. The warm exhaust air cools quickly as it enters the wide chimney flue and some of it condenses into water and corrosive acid. Even though a chimney looks intact from the outside, this condensation can cause a "leak." Installing a double walled stainless steel flex liner can solve this problem.

* Missing mortar
Voids in the mortar joints and spalling (or crumbing) bricks can all contribute to a chimney leak. Masonry restoration with appropriate lime mortars will handle this problem.

* Faults in the crown of the chimney

* Gaps between the flue liner and the chimney

* Very porous bricks
Chimneys in some newer homes are built with bricks which are so porous rainwater seeps through very quickly, causing leaks. Through-wall flashings should be installed to line the inside of the chimney and direct water out onto the roof.

* Problems with an adjacent gutter
If a section of gutter near the chimney is not draining properly, the water may find its way inside and can appear to be a chimney leak. Unclogging the gutters and downspouts, relining box gutters or adjusting hanging gutters is required to fix this problem.
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Old_school (Old_school)
Senior Member
Username: Old_school

Post Number: 403
Registered: 01-2009
Posted on Saturday, February 20, 2010 - 04:05 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only) Ban Poster IP (Moderator/Admin only)

Did they or you install a high efficiency furnace? If so, is it just dumping into the same large flue opening? IF that is the case, I would bet that there is not enough heat coming from the new appliance to push all of the gasses to the outside and what you are seeing is the water vapor condensing while it is still in the chimney. If that happens around here where it gets below freezing in the winter the whole chimney will start to break apart.

If that is the case, you need to install a new smaller metal liner inside the old flue to keep the gasses moving till they get outside. Around Michigan they do this with a flexible pipe that they pull down from the ridge with a rope from down in the basement.
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Slate_man (Slate_man)
Senior Member
Username: Slate_man

Post Number: 567
Registered: 01-2007
Posted on Saturday, February 20, 2010 - 02:29 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only) Ban Poster IP (Moderator/Admin only)

Pictures.
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Pinnacle (Pinnacle)
New member
Username: Pinnacle

Post Number: 4
Registered: 02-2010
Posted on Saturday, February 20, 2010 - 02:06 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only) Ban Poster IP (Moderator/Admin only)

I have a problem. Reslated a house going on 18months ago. Like 99% of them it has a chimney. We renewed all the lead apart from one side, as it was neighbours side. We re bed the top with waterproof mortar (granite mix for strength) and re pointed chimney. Since then we then we have been back endless times as below the roof the chimney is wet coming from the joints. We have waterproofed the stack as a whole, added wider soakers, put in flashings deeper. When we check back gutter, under lead etc there is dust. No sign of water above roof.
We have just done the neighbours side, as this was un pointed and lead was insufficient. We have re pointed, and put wide soakers in. Since this, it has gone worse.
I am now stumped for ideas, please, any help, suggestions would be great.
Knocking down the chimney is not an option as they are having a gas fire fitted and using this for the flue.
HELP

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