Replies

1. 
   Framer | Jul 06, 2005 03:48pm | #1

   Last summer I watched a bunch of guys doing that on a Municiple building using small grinders with diiamond blades. The dust was amazing.

   Joe Carola
2. 
   timkline | Jul 06, 2005 05:19pm | #2

   use a tuck pointing blade in a grinder

   http://www.maxtool.com/cgi-bin/dbsearch.exe?mdb=/tools.mdb,tbl=IC_ITEMS,template=/comp_master_3_merit.htm,DBCOMP=ABS,ReturnMax=25,DBSORT=ITEM,DB_CAT2=MBTPB-S

   the process for the limestone is the same.  usually the joints are tighter in the limestone.

    

   carpenter in transition

3. 
   ripmeister | Jul 06, 2005 05:25pm | #3

   One caveat I have seen regarding the repointing of older structures is to be careful with the hardness of the mortar.  I seem to remember that the older mortars were much softer than they are today and that if you use too hard a mortar that can cause problems.

   I don't remember the rationale behind this.  Perhaps someone else can chime in and explain.

1. 
   BryanSayer | Jul 06, 2005 07:46pm | #4

   I have heard the same thing (about old mortar being softer) and the explanation I heard was "more lime" in old mortar. Don't know if that is the whole story (or even true) though.

1. 
   Piffin | Jul 07, 2005 04:17am | #7

   Maybe more lime, but also less portland - like none. read above 

    

   Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!

1. 
   BryanSayer | Jul 07, 2005 06:16pm | #9

   So is "burned lime" then a replacement for portland cement? That is, would the mixture likely have had both cooked and uncooked lime? What does cooking the lime do? Where did the color come from?This is really interesting. I'm going to need to repoint the back of my house at some point.

1. 
   Piffin | Jul 08, 2005 05:15am | #12

   I don't know enough about it all to say the difference ion slaked and unslacked, but "cooked" is not one I have heard. Here is something that explains old ways of preparing lime for mortarhttp://www.buildingconservation.com/articles/limegauging/limegauging.htm 

    

   Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!

2. 
   EricPaulson | Jul 08, 2005 07:59pm | #14

   This time you are reading my mind...............NO Portland!I Love A Hand That Meets My Own,

   With A Hold That Causes Some Sensation.

   [email protected]

2. 
   Piffin | Jul 07, 2005 04:15am | #6

   The brick were also softer back then. if mortar is harder than the brick, it will damage the brick.Lime mortar is also somewhat self-healing. a small stress crack will heal as rain water leaches lime from one spot and it colleects in the void left between grains of sand.finally, portland cement is only commonly known and available for a littleover a hundred years. before trains, and efficient transport systems were built, most folk had to build with what was available locally, so brick werre thrown and lime burned.
   There are three lime kilns that I know of within twenty miles of me. 

    

   Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!

1. 
   ripmeister | Jul 07, 2005 05:02pm | #8

   I knew there was a logical reason.  Thanks for picking up on that with the explaination.

2. 
   draftguy | Jul 07, 2005 08:29pm | #10

   "finally, portland cement is only commonly known and available for a littleover a hundred years."You beat me to it, I was just going to say this. From what I remember from my architecture classes (a thousand years ago) Portland cement wasn't discovered until the turn of the century (19th -20th). It was actually "rediscovered" . . . the Romans had the ingredients and used it for their walls, aqueducts, etc.. The recipe was mysteriously lost during the collapse of Roman civilization, and wasn't rediscovered until a little over a hundred years ago. Coincidentally, steel was also discovered about the same time by adding carbon to iron. That's when skyscrapers, concrete airdomes and other large structures with large spans started popping up all over the place. A seminal change in construction and architecture, for sure.I also heard the same about being careful using modern mortar in old brickwork. The new mortar is much stronger and more durable, but is less likely to "move" with seasonal fluctuations. If modern portland mortar is used with old lime mortar, the modern stuff isn't as flexible and creates pressure, potentially causing the bricks to crack and shelve. Your locale may have a local historic commission that might be able to help you out if you want to be consistent with other buildings in your area.

1. 
   ButteUptown | Jul 07, 2005 09:48pm | #11

   I've been pointing away at my 3-story 1890 house for 8 years now, and have picked up a few things. Mix your own mortar, get some local sand (like that in your old mortar), lime, white portland (I'd recommend using some , but not a lot for a really old place), and coloring agents. The white portland allows you to match the color of the existing mortar in ways the gray stuff won't allow.
   Before you do anything though, download and read the National Park Service's Preservation Brief #02: Repointing Mortar Joints in Historic Masonry Buildings http://www.cr.nps.gov/hps/tps/briefs/presbhom.htmI know of no better guide to use.
   Larry in Butte, MT

4. 
   gecko | Jul 07, 2005 02:50am | #5

   I'm repointing my house at the moment, which is very old as well. its a bad idea to use an angle grinder for removing the old mortar in the vertical joints because you cannot get the vertical joint cleaned out well enough without cutting into the brick above and below the joint.

   you need to use a very soft mortar with a high lime content. its hard to find it, but it is out there. it needs to be softer than the brick or it will not move with temperature changes enough and will fail, or split the faces off the brick) you also cannot let the mortar dry out after its in the joints so you'll have to spray it with water every once in a while throughout the day. its a good idea to soak the wall you're about to work on before starting.

   the bricks that have lost their faces will need to be replaced. I find the best way to do it is just smash it out with the same tool you use to remove the mortar ( a pointing chisel ).

   the limestone will almost definitely have been installed using the same mortar as the rest of the building, so I would use the same stuff again.

   Custom Cabinetry and Furniture

   http://www.BartlettWoodworking.com

    

    

5. 
   JeffBuck | Jul 08, 2005 06:18pm | #13

   I'd not use a a grinder on this job. I'm no mason by any means ... but I have done more than my fair share of tuck pointing old brick work.

   I'd suggest working with hand tools ... the old fashion way .. simply because you'll never know "where" to stop if using power tools. You will have no feel to tell what's just "normal soft"  ... and what's completely shot.

   and with old, old, old remodeling ... U gotta stop somewhere. Other wise ... you are tearing down and rebuilding completely. It's stood this long ... no sense screwing it up now.

   Jeff

       Buck Construction

    Artistry In Carpentry

        Pittsburgh Pa

6. 
   ponytl | Jul 09, 2005 03:36am | #15

   I do this way more than I'd like... 

   what you are dealing with is infact lime puddy...ie: lime mortar... has about 250psi vs  about 2500psi for portland type s

   notice no expanion joints in old brick buildings... because they move and as others have said are self healing... usually 3 ...4.... 5 courses thick... and never filled with  mortar between the courses... thats what makes em weather proof (gives water a place to go) and lets em move  ie: contract/expand...

   if you ck the net you can get all the info you want on the "proper historic way " to tuck point and to clean the joints... and like others have said..."where do you stop" ?

   now.. what i do... and i don't live where we have a ton of freeze/thaw

   first... i pressure wash  you can eat up the bricks this way so u need to be careful... but this will give you an idea of what ur deal'n with...  i like 3/4 of an inch deep to fill... but it's not cast in stone... I have stuff hold'n up with 1/4" thats been there for 10yrs....

   i use mostly lime... but i do use 20% white type III portland... use'n lime only it has to dry... portland "sets"  and lime only can take a long time to dry... u can keep buckets of it for years if it's covered and wet... i use grout bags to fill the joints... i really wet the brick first or in my experience it just sucks the moisture out of your mix... i give it some time then strike the joints... then follow with a wisk broom for clean up  about 20 min after jointing...

   they say to try to find the local source of sand that was used from when it was built...  but really sand in layers will never be the same...

   do the best you can,,, don't sweat if it doesn't match perfect because it won't...  and  know when to stop... 50 years from now someone will be glad you did what you did... when u did it

   pony