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Mortar mixing ratio

267K views 170 replies 36 participants last post by  Tscarborough 
#1 ·
Ok dumb question time. As some of you may know Im still new to the brick laying trade. So far I have only done some small projects and heve been using the premixed morter. I now have a project that would be better using some sand and cement and mixing my own morter.
What I need to know is what is the best mix ratio. I have looked around the internet and found a few charts that only confuse me. So I figure that I had better consult the all knowing wise masters on this one.
Thanks in advance
Smitty
 
#58 ·
I really appreciate the comments and feelings on mortar/mud.

The whole suject is very vague because of the different sands, personal experiences and the whole question of workability.

If you really look at the specs for the mortar, there is just one type cut up into different sections/Types depending on the proportions. It is further complicated by the use of performance measure that are restricted to lab tests, since site tests are a folly. Even 1 ounce of cement or lime in a batch can change a mortar from a Type N to a type S technically. This does noy even adress the differences in sand gradation ans more importantly the shape of the sand particles. When we sold sand, we had two suppliers and most contractors had their prefernce on the type/producer because they based their productivity of one of them and had to make a few costly adjustments that cost money.

Since I am a voting member on the ASTM mortar specifications, it is good to hear the opinions and make the national standards and specifications fit to the real world and then the performance. - More cement is not the solution.

Thanx -
 
#61 ·
Proper mixing procedure for Type S mortar

‹ Back to FAQsWhat is the correct Mortar Mix ratio for Masonry?
The experts and I agree that with pre-mix bags available, unless you are on a major jobsite with at least a dozen masons it's just not worth mixing yourself. However, if you are inclined to do so our friends at Superlite Block have provided the industry standard directions below.

There are a variety of mortar mixes that the mason contractor can mix up, depending on the type of material that is being installed:


Type M (2500 psi)
Type S (1800 psi)
Type N (750 psi)
The different types are achieved by varying the ratio of Portland Cement, Lime and Sand. Type S mortar is the most common for the Arizona market so we will use this as the basis for our comparisons.

There are three primary ways to make mortar:


1.Portland Cement, Hydrated Lime and Masonry Sand
2.Masonry Cement and Masonry Sand
3.Pre-mixed Mortar
The Portland Cement, Hydrated Lime, Masonry Cement and Pre-mixed Mortar are available in bags, the Masonry Sand is generally available in “bulk quantities” that are delivered by a truck or can sometimes be purchased in big “super sacks” from the big box retailers.

Portland Cement
94# bags

Lime
50# bags
Masonry Cement
70# or 78# bags
Pre-mixed Mortar
60#, 80# or 94# bags
Masonry Sand Usually a pile of sand is delivered to the jobsite by a dump truck. The sand is measured into the mixer by means of a standard square point shovel that is “mounded full”. This is referred to as a “shovel of sand”

Portland Cement, Lime and Sand

This is the “old school” method, the standard for the industry that all other methods are compared to. In order to make a Type S masonry mortar one would proportion the materials into the mixer in this manner;

1 bag
94# of Portland Cement
½ bag 50# Hydrated Type S Lime
28 “Shovels” Masonry Sand
7 to 8 Gallons Clean Water

Mixing Procedure:


Put 2/3 to 3/4 of the water into the mixer
Add the Portland Cement and Hydrated Lime to the batch
Add the sand into the mixer, adding water as necessary to achieve the desired consistency
Mix for 5 minutes in a mechanical paddle type mixer
Amount of water required to make good mortar will vary depending on the desired consistency of the mortar. For stiff mortar use less water, for wet mortar use more water. If you do not add enough water the mortar is so stiff that it is unworkable and very difficult to use, if you add too much water the mortar turns to “soup” and you will be unable to use it.

Masonry Cement

Masonry Cement is simply a product that has Portland Cement and Hydrated Lime already blended together in the proper proportions. In order to make a Type S mortar with Masonry Cement one would proportion the materials into the mixer in this manner:

1 bag 70# or 78# Masonry Cement
18 to 20 “Shovels” Masonry Sand
5 Gallons Clean Water

Mixing Procedure:


Put 2/3 to 3/4 of the water into the mixer
Add the Masonry Cement to the batch
Add the sand into the mixer, adding water as necessary to achieve the desired consistency
Mix for 5 minutes in a mechanical paddle type mixer
Add water to achieve desired consistency of mortar, less water for stiff mortar, more water for wet mortar.

Pre-mixed Mortar

This is the easiest mortar of all to make. Pre-mixed mortar is a combination of Portland Cement, Hydrated Lime, and Masonry Sand already blended together in the proper proportions to make a Type S mortar. All that is needed is to add sufficient water to achieve the desired consistency, usually about 5 to 6 quarts for an 80# bag. Pre-mixed mortars are a little unique in that they require a slightly modified mixing procedure.

Mixing Procedure


Put 2/3 to 3/4 of the water into the mixer
Add the Pre-mixed mortar into the mixer, adding water as necessary to achieve the desired consistency
Mix for 3 to5 minutes, turn off the mixer and allow mortar to “slake” for 2 to 3 minutes, re-start the mixer and mix for an additional 2 to 3 minutes adding water as necessary to achieve desired consistency.
Pre-mixed mortars use a kiln dried sand that has a higher water demand. It takes a few minutes for all of the water to be absorbed into the dry sand, hence the need for a prolonged mixing time. If you do not allow the mortar to set and “slake”, it will feel gritty on the trowel and will be difficult to work with.

All of these mortar may be mixed by hand in a wheelbarrow or “mud tub” for those of us who do not own a mixer. A mortar hoe is a great tool when mixing by hand, as well as the obligatory square point shovel. I have found from past experience that a standard construction grade wheelbarrow is too small to mix a full bag of Portland Cement, ½ bag of Hydrated Lime and 28 shovels of sand. It will just barely fit 1 bag of Masonry Cement and 18 to 20 shovels of sand. A standard wheelbarrow very comfortable fits 3 of the 60# bags of Pre-mixed Mortar, or 2 of the 80# or 94# bags of Pre-mix Mortar. Follow the same mixing procedures as when using a mechanical paddle mixer.


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#67 ·
‹ Back to FAQsWhat is the correct Mortar Mix ratio for Masonry?
The experts and I agree that with pre-mix bags available, unless you are on a major jobsite with at least a dozen masons it's just not worth mixing yourself.
There are a variety of mortar mixes that the mason contractor can mix up, depending on the type of material that is being installed:


Type M (2500 psi)
Type S (1800 psi)
Type N (750 psi)



Masonry Cement

Masonry Cement is simply a product that has Portland Cement and Hydrated Lime already blended together in the proper proportions.

Who are these experts? i disagree wholeheartedly. Unless your only laying a few square feet, mixing your own is much easier and cost effective. You only have to worry about keeping the cement dry not the 3x extra pallets that you'd need for premix. And even shovel batching is more than consistent enough for most brick or block jobs and if it isn't, pails aren't all that slow and provide for very accurate mixes.

Also you forgot type "K" and type"O" mortars. Type K is the reverse of a type S having about 2x as much Lime as Portland and achieving around 400psi if I remember correctly. Type "O" is the reverse of a type "M" having at least 3x as much Lime as Portland or even no Portland at all. And yes I do lay up with a type K fairly often. I know neither one is common but they should be mentioned

And masonry Cement around here (made by Lafarge, St. Marys, Italcementi, and Holcim as well as others) generally consists of Portland with plasticizers but no Lime unless you buy a bag of "high bond" The plasticizers are similar to the old Sealbond or Mortar Mate
 
#63 ·
I am in the business of making masonry mortars, grouts and stuccos for the Amerimix line of masonry products. This little ditty was something that I wrote for a home improvement radio and internet program called "Rosie on the House". They said that they had many inquiries on how to make masonry mortar so I put this together for them. I am in Arizona so this applies here since we are a very large type S market and primarily Portland Cement and Lime rather than Masonry Cement for commercial since we do seismic conditions here. On the left coast and other areas with higher seismic activity they tend to use a lot of type M with Portland Cement and Lime.
I know that East of the Mississippi they use primarily type N and usually Masonry Cement
All of these materials are available either field mixed with a sand pile and bags of powder or pre-mixed, just add water
 
#68 ·
Thanks for post but...I find it sort of useless...you had a lot of inquiries about how ot make masonry mortar?! from whom? DIYers,hacks,illegals who are clueless?

This just doesnt make sense to me mainly because what you described is described in detail on the back of any bag you buy.

I think dom-mas provided more info with his 20 sentences than you with first post.

Please dont take offence.

and I agree with dom-mas,unless you are laying 50-100 sq ft using any sort of premixed stuff is terrible...

Have you personally tried using any pre-mix? I have usex Spec-Mix type S and Spec-Mix Stone Veneer Mortar on several occassions...

It runs at about 12$ a bag after taxes,spread is terrible,I scan parge about 40 sq ft with it up to 60 sq ft is lucky.

At the same time with one bag of Lafarge MCS I can probably get 200-250 sq ft.

So in a long run I am losing 45$ every 200 sq ft and thats just scratch(not mentioning the lay itself).

I think you might have to review what you inform public about.
 
#70 ·
I've also never heard of this method of machine mixing where you put the cement in before any sand. If you add the cement first 2 things will happen. You'll weaken the mix quickly by having the cement go off because of the overabundance of water, and also there will be a lot of cement on the inside surface of the mixer which doesn't get into the mix.

The way I do it and the only way I've seen done (and I've worked with guys who've worked coast to coast and it's always the same) is to add 2/3 or so of the water, 1/2 the sand, then the dry goods, then the rest of the sand with a fe secs between each step and each unit of sand. Allow to mix a few minutes. If time allows shut the mixer off and allow the mix to slake a bit then mix again for a further couple minutes.
 
#71 ·
The way I do it and the only way I've seen done (and I've worked with guys who've worked coast to coast and it's always the same) is to add 2/3 or so of the water, 1/2 the sand, then the dry goods, then the rest of the sand with a fe secs between each step and each unit of sand. Allow to mix a few minutes. If time allows shut the mixer off and allow the mix to slake a bit then mix again for a further couple minutes.
Pretty much same here...I add all 2/3 of water with my additives,1/4 of my sand,then bag of cement,then my lime,then i put my buckets of sand then I add rest of my water to get mix to right consistency...
 
#77 ·
Just don't too wrapped up in the use of high strength mortar for masonry (block and brick).

Read Appendix 1 of ASTM C270 (Standard Specifications for Masonry Mortar) since it clearly advises about the folly of high strengths and the value of workability to get good workmanship and other properties. The subject did not fit into the specifications for mortar, but it was justified to include it as an informative item for good construction. No all engineers get hung up on numbers and higher strengths.

Mortar really has very little effect on the compressive strength of a wall (even 20 stories of load-bearing partially grouted block) and other properties can be much more important.

Just a similar repeat of TS's comments from someone that writes the specs.
 
#78 ·
HeatStop 50. Mixes with Portland don't handle the 'cycling', or cooling down well. And as I recall, mixes with fireclay don't generally qualify as 'refractory', at least, not to satisfy current codes. This may be a perfectly good mix for some things, but for a true refractory mix......HeatStop 50 is the stuff.
 
#84 ·
A normal weight (or heavyweight) CMU is almost 2 hours unless the core design and slightly thicker (1-5/8") face shell give it more fire resistance for a 2 hour rating. Many manufacturers make a 2 hour heavyweight unit.
 
#92 · (Edited)
Tell him to glue some 5/8ths drywall to the wall. Refractory parging sounds EXPENSIVE

I just looked at some charts. If you grout every core solid in an 8" wall then you should have your 6 hr rating. You could also fill the cores with roxul or an approved aggregate but I think grouting would be cheaper and faster. Not cheap but cheaper
 
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