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-   -   Mixing Mortar for Tuckpointing (http://www.diychatroom.com/f19/mixing-mortar-tuckpointing-35780/)

amakarevic 01-12-2009 09:34 PM

Mixing Mortar for Tuckpointing
 
i went through several how-to pages but none prescribed a ratio of cement vs. sand. can anyone give me a ballpark of what i should be mixing ? saying "Mix the mortar to a consistency like pudding, where you can slice a piece off with your trowel" really does not specify any ratio. e.g. 80/20, 70/30, 50/50, i have no clue.

http://homerepair.about.com/od/exter...uckpoint_3.htm

also, what kind of a "liquid latex binder" should i be using ? and what is it ?

Crosby 01-13-2009 10:01 AM

Quote:

Originally Posted by amakarevic (Post 211778)
i went through several how-to pages but none prescribed a ratio of cement vs. sand. can anyone give me a ballpark of what i should be mixing ? saying "Mix the mortar to a consistency like pudding, where you can slice a piece off with your trowel" really does not specify any ratio. e.g. 80/20, 70/30, 50/50, i have no clue.

http://homerepair.about.com/od/exter...uckpoint_3.htm

also, what kind of a "liquid latex binder" should i be using ? and what is it ?

You didn’t mention in your post what type of mortar you are using. What kind of mortar was used originally? How old is the structure? What type of brick you are dealing with? Selecting the right mortar for the job is important. If you choose a high compressive mortar with old soft bricks you will destroy the bricks. Ultimately you want to match what’s there. . With no information I can only generalize. Unless you have an old lime mix, a general pointing mortar is type N for exterior applications. I would use a lean 1:3ish mix for pointing with type N. It’s easy to batch using 5 gallon buckets. The liquid binder is a bonding agent which can be picked up where you get the rest of your materials. It will also make the mortar a little sticky which is desirable due to the lean pointing mix. Don’t over do it with the binder, follow the directions.

amakarevic 01-13-2009 11:07 AM

this is an interior exposed brick wall in a basement apartment and the house is 100 yrs old. the old mortar is in relatively decent shape but slightly dissipating. i mad a pilot run on just a few bricks last night that will not be exposed and used type N cement. when you say 1:3, do you mean 1 for cement and 3 for sand or vice versa ?

Crosby 01-13-2009 01:07 PM

Quote:

Originally Posted by amakarevic (Post 211993)
this is an interior exposed brick wall in a basement apartment and the house is 100 yrs old. the old mortar is in relatively decent shape but slightly dissipating. i mad a pilot run on just a few bricks last night that will not be exposed and used type N cement. when you say 1:3, do you mean 1 for cement and 3 for sand or vice versa ?

Thats right around the time they stopped using the lime and sand mix in masonry construction. In general, mortars for repointing should be softer (measured in compressive strength) than the masonry units and no harder than the original mortar.If you got Type N you should be okay, it's a medium compressive-strength (750 psi) mortar with a high lime content. It's made of 1 part portland cement, 1 part lime and 6 parts sand. The lime and portland are factory mixed in the bag, so that translates to 1 part mortar to 2.5-3 parts sand.

amakarevic 01-13-2009 01:38 PM

Thanks Crosby !

Crosby 01-13-2009 01:47 PM

Quote:

Originally Posted by amakarevic (Post 212069)
Thanks Crosby !

:) No problem, good luck with the project.

Tscarborough 01-13-2009 05:06 PM

Good info Crosby, but as a rule, a premix mortar is going to consist of sand and masonry cement, not portland cement and lime. If you are going that route, make sure that the bag states that it is a portland cement/lime blend.

Type N is the strength designation, not an ingredient designation.

4just1don 01-13-2009 10:26 PM

I wanna hijack this thread. How is the best way to get it into a vertical wall? In MY case its regular 8X16" concrete blocks,,,maybe 50 years old. looking a it from the inside out, no mortar to be seen anywhere for about a 4' section. Is there a 'proper' tool for getting it where its supposed to go??? The outside of ths area is the back door step of about 8" which puts it about at the top of this 3 course crawl space(from the inside)

Bob Mariani 01-14-2009 07:07 AM

The right concrete mix ratio can solve problems or it can create them. What you really want in a concrete mix is one that is easy to place, strong enough to meet the needs of the application, durable for the life of the floor or wall, and that will look good when you're done with your decorative efforts. Don't rely on bags! Rather than only specifying how much cement is in the mix we should be specifying things like permeability, shrinkage, workability, pumpability, stampability, and stainability.

The lime content contributes to the sticking attribute. The water will give you workability, to more you add the weaker the cement. (mortar is also a cement) The sand is the aggregate that the cement binds to. a 2.5 -3 parts sand to one part cement is a good choice for your task. With 1.5 part lime. The sand should be mason sand not play sand, beach sand or even concrete sand.

amakarevic 01-21-2009 12:14 PM

Quote:

Originally Posted by 4just1don (Post 212335)
I wanna hijack this thread. How is the best way to get it into a vertical wall? In MY case its regular 8X16" concrete blocks,,,maybe 50 years old. looking a it from the inside out, no mortar to be seen anywhere for about a 4' section. Is there a 'proper' tool for getting it where its supposed to go??? The outside of ths area is the back door step of about 8" which puts it about at the top of this 3 course crawl space(from the inside)

here ya go:

http://www.diychatroom.com/f19/morta...ointing-35149/

amakarevic 01-21-2009 12:18 PM

hey guys - i did 3 parts sand and 1 part type N cement but the mortar, when it dried, was more dissipating/sandy than i'd like it to be. it wasn't as smooth as i'd like it to be and you could rub sandy particles off with a finger.

on the other hand, i had done a pilot run on a few bricks before this with 1:1 mix and that looks like i'd like it to - the mortar almost looks like grout between tiles.

my next question is: are there any consequences to doing a mix closer to 1:1 for the aesthetics of it ? will the strength be compromised ? what does sand do ? to me, it seems like pure cement would be the ultimate strength. please someone explain.

Bob Mariani 01-21-2009 01:00 PM

Quote:

Originally Posted by amakarevic (Post 216729)
hey guys - i did 3 parts sand and 1 part type N cement but the mortar, when it dried, was more dissipating/sandy than i'd like it to be. it wasn't as smooth as i'd like it to be and you could rub sandy particles off with a finger.

on the other hand, i had done a pilot run on a few bricks before this with 1:1 mix and that looks like i'd like it to - the mortar almost looks like grout between tiles.

my next question is: are there any consequences to doing a mix closer to 1:1 for the aesthetics of it ? will the strength be compromised ? what does sand do ? to me, it seems like pure cement would be the ultimate strength. please someone explain.

The sand is the aggregate. Like I said you need to use the right type of sand. (size). You did not. mortar That has a high cement content, excessive shrinkage of mortar from the face shell of the masonry unit is more likely to occur. The size of the sand and the ratio with cement will determine the compressive strength of the mortar. In block you want a lower psi of 1800 Type S, although above ground many masons will use Type N PSI of 750. Type N is fine but is used in brick work more than in block work. the lower PSI mortar has more adhesion and will allow a block wall to expand and move better. Type N mix ratio is 1:1:6 Type S mix is 2:1:9 The ratio I gave you is somewhere in between giving you adequate strength and adhesion. You can see here that the added sand in Type N has made it a stronger mix.

amakarevic 01-21-2009 01:31 PM

i got the multi-use sand from HD, it listed custom mortar applications on the bag. the only other kind they had was play sand, which is not applicable here. but i have been disappointed in HD many times, should i look elsewhere. and also, this IS a brick wall, so is type N cement OK ?

amakarevic 01-21-2009 01:33 PM

Quote:

Originally Posted by Bob Mariani (Post 216752)
Type N mix ratio is 1:1:6

do you mean 1 water : 1 cement : 6 sand ?

Bob Mariani 01-21-2009 01:40 PM

Quote:

Originally Posted by amakarevic (Post 216781)
do you mean 1 water : 1 cement : 6 sand ?

no... cement : lime : sand Use mason sand not all purpose sand, that is why you have a grainy feel. The sand needs to be fine and have sharp edges. The cement bonds to the sand, so the more edges the better the bond. The amount of water needed: Enough to make it workable. Too little and it is not pliable. More than needed, you weaken the mix.


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