"dicko" wrote in message
...

First a bit of history.

My Chimney has been pointed twice in th e10 years I've owned my house.
The first time about 9 years ago, the second about 3 years ago.

The first time, it looks like the guy just scraped out about 1/4" of
mortar and filled it back in. Now that thin layer of new mortar is
falling out. However, its still hard as a rock.

The second time, just a few spots were patched but the mortar used
looks like it has turned to sand and is disintegrating. I've been able
to remove a few bricks where this is happening.

I figure I can do just as good a job as the "professionals" who
screwed it up before so I'm going to give it a try.

The question I have is what type of mortar is used? I see the home
centers sell a type N mortar mix and a type O mortar mix. Type N being
stronger and is used for exterior walls and type O being weaker and is
sometimes called pointing mortar.

So far I have all the affected joints cleaned out to about 3/4 inch
depth, and all the old mortar has been cleaned from the few bricks
that I was able to remove. I ready to put the new mortar and bricks
back in.

-dickm


The correct way to do pointing is to have the existing mortar tested for its
exact ratio of sand, lime, and cement. You need to take samples from
several sections as the mix may have changed with each batch during the
original construction. Once you know the correct ratio, you mix your own to
the same specifications.