Repointing Brick

dirt diggler

i have the opportunity to re-point an old brick deck if I want. Still thinking about it. I am NOT a mason ... i have enough masonry experience though - im confident with some advice i can handle it.

Mortar joints are to be repointed


i've set flagstone before - but NOT brick


i can't even remember the right mix, now that I think about it. I think I've done 3:1 sand/cement.



anyways - i could go on ---

but looking for *right* advice on the following:


what type of mix to use (contents, ratios)

just any general advice - as the posts come in, maybe ill get more focused questions

thanks DD

tkle

3 to 1's about right.I like about 2.5 to 1.Half a shovel of lime will help it go through a grout bag.Dig out any lose joints and reset any lose brick.Not much to it.What type of brick?Are the joints washed or tooled?Is the grout course or smooth like tile grout?

dirt diggler

yeah - a good portion of the joints are crumbled to the point I can pick them out (i could take a chisel and bust those up and probably get a lot out with a shop vac)

the rest i'll grind down about 1/2 inch

not sure what you mean by washed or tooled (im assuming washed means it was dry grout mix moistened after being placed - tooled being wet grout???)


it's coarse ... not smooth

how come some grout turns out cement color - while other grout has a yellowish/sandy color to it

tkle

Washed or tooled refers to how the joint is finished.Trying to match the existing grout.The grout can be troweled into the joints using a dryer mix or put in with a grout bag using a wetter mix.It is then cut flush and sponged over similar to tile smoothing it out and wiping the paste off leaving the sand more exposed or tooled with a tuck pointer or a rounded jointer giving it more of a slick look leaving the paste on top similar to troweled concrete.The difference in color may be due to the grout being improperly mixed in the first place or from the top of the grout(the paste)deteriorating due to freeze thaw action.Different methods are used where freeze/thaw is a major problem.

Tscarborough

Even though this is brick, I hesitate to call it tuckpointing. You are doing the same thing, but on a horizontal plane. All of the stresses and requirements are different for grouting (flatwork) than for tuckpointing (vertical).

Generally, I recommend a soft mortar for tuckpointing to increase bond strength and reduce shrinkage. For flatwork, I can see using a stronger mix, and including an entraining agent. A good mix would be 1 part portland, 1/2 part Type SA lime, and 2-1/2 parts good sharp sand by volume of cementious materials.

The depth of the replacement joint should be a minimum of the width, and deeper is better, though not required.

My only question would be if the deck served as a ceilinig or is it on the ground?

dirt diggler

ok -

what's the purpose of having lime into the mix

Tscarborough

Lime does 3 things:

First, it delays the set of the mortar. One of the major differences between concrete and mortar is it's pot life, and the ability to have it "set" and then shake it up and reuse it, i.e. "tempering".

The second thing it does is make the mortar stickier and more "creamy". It does this by reducing the required amount of water for a given amount of ingredients and by entraining micro-capsules of air.

The third effect is less shrinkage cracks, and a process called "autogenous healing", which is a characteristic of lime based mortars and stuccos.

dirt diggler

i think my only concern is matching the existing grout that he doesn't want removed ...

im picky and tedious enough to do a thorough job

it's just blending everything in


tscar - sorry - no not a ceiling - a patio

Tscarborough

That is good, because if it were, my only advice would be to flee.

Tscarborough

The only way you will be able to match exisiting grout is to rub so much dirt on both that it doesn't matter.

tkle

Another question is why the grout is deteriorating in the first place?The entrained air gives the moisture a place to expand when it freezes without popping the mortar.Correct me if I'm wrong Tsc.I'm not an expert on cold weather.

dirt diggler

Tkle -

not sure honestly ... there's a couple hairline cracks. I think the brick is set on a concrete sub-base and there is definitely evidence of heaving.

I'm not to fix that - just purely making cosmetic touch ups here - and HO's aware of that

Tscarborough

You are pissing into the wind, then, and should tell the HO that.

dirt diggler

i guess he'd have to have the entire deck redone to have something that wasn't just going to come back i guess ...

it's not abundant with cracks ... about 3 major areas (the brick is a good 1/4" higher than the others that these points)


i think if it's coming from heaving -- he needs to take the concrete base out ... essentially start over

Tscarborough

Segmental Concrete Pavers are his friend.

tkle

Do it quick and get paid quick.The repair might not last long.

Tscarborough

I dunno, the arbor on that thing doesn't look too precise to me......

__________________
It ain't Rocket Science unless you are building rockets.

lukachuki

Good eyes! I guess that is why they are Precisiondiamondinc.com they should change their name to unbelievablevibrationdiamondinc.com

__________________
"The problem with internet quotes is, you never know if they are authentic." -Abraham Lincoln-

Less with the jaw more with the paw!

dirt diggler

you daggon right I'm not a mason.


I learned a HELLUVA lesson on this job ....



STAY IN YOUR BOX, guys.



Stay in your box. Especially now, with the economy .... be careful how you appraoch "diversifying" your services. Not a whole lotta jobs to pick from now ... so the ones you get, gotta be profitable

__________________
Thanks in advance!!!

nycballer31488

Deep cutting the joints with a diamond wheel or an arbortech is a key step in the process. We have done entire buildings in Manhattan. Your motar mix should be up to par and consistent. Pressure washing all areas to be pointed is a critical step in the process. It allow for better adhesion. Me an my customer prefer tooled joints. It gives the building a cleaner look.