# Jointing Bluestone



## lukachuki (Feb 11, 2005)

Hey guys,

I just spent a whole week including today (saturday argh) facecutting bluestone flags for a long sidewalk. (no pics yet...keep forgetting the cam) I am real glad to be done with the setting of the stones (using type N on 4" conc footing) the first couple of days it is fun but on day 3 or 4 your mind begins to wander and concentration is easily lost.

My big question is about the joints which I will do on Mon. Should I modify my regular mix of type N mortar (1 bag to 16 shovels sand) when I bag and strike the joints? A little lime or portland maybe? This stone is very soft and I want good adhesion to keep creepy crawlies and moisture out. Also any tricks for finishing the joints? I thought I would just cut'em flat after the mortar has set up using my tuck pointer but there has to be something more elegant I could do. Maybe use a stick off a nearby tree or something.  

Thanks
Tim


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## tkle (Apr 15, 2006)

A half shovel of lime will help the mud go through the groutbag a bit easier.A simplier way is to use 1# coffee cans and pour the grout into the joints.After initial set cut the mud flush then sponge the joints with a good quality tile sponge.Wash each stone individually,rinsing your sponge with each pass.Keep changing water.When you think it's clean wash it one more time to get any film.Generally three passes will do it.Do small sections. Usually I can go back the next day and acid wash.Even though the stone is "clean",it still helps to bring out the color.

I like a mix of about 1/2.5,portland/sand.I like to use
2 buckets of portland to 4 buckets of 30 grit silica sand and 1 bucket of 60 grit silica.Some people don't use the 60 grit.Some people like to throw in some mason's sand,some like all mason's sand.A pinch of lime will help it flow and stop water seperation.More lime or cement will make a stickier mix,making it harder to clean up.The 60 grit will make a tighter grout,however too much will weaken it and make it harder to clean.


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## denick (Feb 13, 2006)

I'll add what we have been doing for at least three generations. We are in New England for reference to weather problems.

We mix portland cement 1 part to 3 parts sand. Add just enough water to have a consistency like the topping of crumb cake. If you grab a hand full and squeeze it you should just barely feel moisture on your hand.

Get on you knees and press firmly into joint. All voids are filled. Easily worked to any finish. No mess, no clean up. And I can show you work that has withstood our weather for over 80 years.

I know! "thats the way dinasors did it". I've heard that so many times. But I'm not going to change.


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## tkle (Apr 15, 2006)

denick said:


> I'll add what we have been doing for at least three generations. We are in New England for reference to weather problems.
> 
> We mix portland cement 1 part to 3 parts sand. Add just enough water to have a consistency like the topping of crumb cake. If you grab a hand full and squeeze it you should just barely feel moisture on your hand.
> 
> ...


You do have a point.A dryer mix will definatly be stronger.I use a bit more cement.That helps make up for it.I've never had a problem wyth the first method,however as you pointed out,your grout has held up in New England weather.I live in sunny southern Cal.It could very well be a regional thing.Either way I prefer washed joints.

Another point.When I lay the stone I make sure and point around them while the base is still wet so when I grout I'm only laying a bead about 1/2" deep.


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## dennis (Nov 17, 2004)

denick,

What type of sand? ( does it matter ? )

Do you have some pics you could post?

I have a customer looking for options/ideas.


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## denick (Feb 13, 2006)

dennis,

We use our local mason sand. Any grit in the sand makes it hard to finish. 

I don't have any pictures of joint finishes. But that is very dependent on what stone is used and on how the stone will be layed.

What's an option is in the person doing the finishing.


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## tkle (Apr 15, 2006)

A silica sand grout will be very tight and looks the same as sanded tile grout.Grout made with mason's sand will be somewhat stronger and less prone to cracking due to larger and more angular grains.It has a rougher look.Silica grout works better with smaller 1/2" average joints.Wider and you'll start getting shrinkage cracks due to the fact that the silica,being less angular,holds the water less effciently.The wider the joint the more mason's sand I would use .For 3/4" average joints,I would substitute the 1 bucket of 60 grit with 1 bucket of mason's sand.


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## Jo Anne Moore (Oct 12, 2006)

Hi ,

try Polymeric Stone dust. I have just discouvered it and its saving me alot of headaches.It helps prevent ant hills and weeds.It hardens like concrete but softens when it rains so it has flexability. Its suposed to last a life time if installed correctly.I used the polymeric sand on a paver job. its for joints 1" or less. I was really impressed. I checked there web site. The Stone Dust is for natural stone. joints up to 4". Very impressive stuff. The site is alliancedp.com. You can find out where to buy it around your area. The # is 1 866 212 1611. Hope this helps out! Jo


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## dennis (Nov 17, 2004)

Options as in smooth vs coarse. As tkle mentioned about smooth tight silica grout or mason sand. Color is a factor also.
Joints avg. 3/4".
The walkway was re done about 8 yrs ago and the joints have either popped or crumbled.


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## lukachuki (Feb 11, 2005)

Hey thanks guys for all the suggestions. I'm sorry to hit and run with the question but I have never had a busier 2 weeks in all my life. My wife and I have been doing the foster kid thing as well as working shorthanded.

We completed the sidewalk today but still have no pictures. I will try to get some pictures soon and post them to this thread.

I gave great consideration to which mix to use on thes flags. I definately want to try denicks crumb cake portland mix but I had a few questions about consistancy (never eaten crumb cake) that I didn't have a chance to ask. I ended up using 1 bucket portland to 4 buckets mason sand and 1 gallon of lime. Time will be the test but I really like the consistancy that it the lime gave the grout. I ended up concave jointing the joints as I didn't have time to sponge them as I was on extremely short schedule and time was of the essence. I finished acid washing it tonight in the dark. Man hope I sprayed off that last section!!!!!

Thanks again for all the input. And yes Jo Ann I love the polymeric sand for soft set pavers or stone it really makes things easy and is a great great product this time though I wanted the real thing.


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## CJKarl (Nov 21, 2006)

denick said:


> I'll add what we have been doing for at least three generations. We are in New England for reference to weather problems.
> 
> We mix portland cement 1 part to 3 parts sand. Add just enough water to have a consistency like the topping of crumb cake. If you grab a hand full and squeeze it you should just barely feel moisture on your hand.
> 
> ...


Been doing it that was for 20 years.:thumbsup:


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