Mix Mortar

For your bricklaying project, learning to mix up the right amount of good mortar will save you time and money. You don't want to let your mortar dry out or mix at the wrong consistency. By learning the right proportions of ingredients and the proper steps for mixing and working your mortar, you'll be mixing up good batches of mortar in no time. Get that block project started.

Steps

Learning the Recipe

  1. Measure three parts sand to one part masonry cement. For a basic mortar mix, you'll want to mix essentially three parts of sand for every one part of cement you use. If you're mixing up a whole bag of cement, that'll mean you'll use three times that amount of sand, which will result in a big batch of mud. Only mix up as much as you'll need.[1]
    • The measurement doesn't need to be precise as a baking recipe. At most work sites, when mixing large amounts, the amount of sand is usually given in "shovels full" per bag of mortar mix, which usually works out to somewhere between 15 and 18, depending on how large the shovel scoops are. It's important to get close, but it's more of an eyeball measurement. You don't need to get out the teaspoons.
  2. Use the right amount of water. A bag of mortar should be mixed with about three gallons of clean water to achieve the right consistency. The amount of water used can vary drastically depending upon the weather, how wet the sand is, and the variety of mix you're using, so read the instructions carefully before adding water.
    • Ambient conditions ( temperature and humidity) will affect the mix and need to be considered.
    • A drier mix will yield a stronger bond. A wetter mix might be easier to work. That's where experience comes in.
  3. Use the correct sand and mortar. Using a fine-grade, sharp masonry sand for the job is more appropriate than other varieties, and using fresh unopened bags of masonry cement will be more effective than using older bags. Masonry cement mixes, like Quikrete, Sakrete, and other brands are all appropriate for the job.[2]
    • Some brands come pre-mixed specially for mortar, which means you don't need to add sand. These are somewhat more expensive than regular Portland cement, but are much better for smaller projects. Read the label and find out what you're getting. If you don't need to add sand, the mixing process is still the same.
      1. Portland cement is not a brand of cement. It is the name of the most common type of ingredient used to mix mortars, concrete and other bonding mixes.
    • Keep the sand and dry cement covered to keep them as dry as possible. It's easy to ruin your materials if they get too humid and damp. Try to mix up only as much as you'll need, but also to use up what dry mix you have so that you can take advantage of your materials.
    • Check your cement bags for lumps. If there are lumps or hard chunks on the bag, it has been exposed to moisture and won't bond well, it needs to be discarded.
    • Different brands may recommend slightly different mixes. Read the label on the brand of mix you buy and follow the instructions. In general, however, a mix of 3-to-1 is usually appropriate and effective.
  4. Consider using lime as an additive. In some areas where the wall you're building will be exposed to especially high winds or the elements, lime is added to increase the bonding and strengthen the stonework you're building. If you do elect to add lime to your mix, you'll also need to add more sand to balance out the ratio somewhat, resulting in a stronger, more bonded mortar.
    • An appropriate ratio if you want to use lime would be six parts of sand to two parts of lime to one part of cement.
  5. Keep in mind that adding lime to your mixture will make the mortar set more quickly. This means that you need to work more quickly or mix a smaller batch.
  6. Match the recipe to the weather. In very wet, cold, or humid weather, the mortar will behave differently than if it's really hot and dry weather. You may find it more effective to use slightly less sand and slightly more water if that's the case. Experiment some to get the right consistency and mix.
    • In general, it's easiest to use mortar in moderate, dry weather than, cold and humid weather. While that's not always possible, you can learn to recognize the right consistency and add water appropriately.
  7. Mortar mixed to the right consistency should hold onto a trowel held at a 90 degree angle, but should also be wet enough to work easily and pour into and out of buckets.
  8. If working on cold, near freezing weather, try adding slightly more lime and hot/warm water to aid the hydration reaction of cement and help it set quickly. Keep in mind that the finished product must be kept from freezing until set.[3]

Mixing a Batch with a Mixer

  1. Wet the mixer, wheelbarrow, and/or buckets. Before you start adding dry ingredients, you need to wet all the things that you'll mix in, carry the mortar in, and use the mortar with so the mortar will slide off easily and reduce waste. Slosh about half the water necessary for the batch you're making into the mixer or the tray, and pour some water into the wheelbarrows or buckets you'll be carrying it in.
    • Depending on the size of your project, you be using a small mixing tray or you may want to use a gas-powered mortar mixer to mix large quantities of mortar. These feature several spinning blades that can hold up to three bags of 80 lb. mix, cutting down on the elbow-grease necessary to mix up a batch of mortar mud. Consider renting one for your job, especially if you'll be working over the period of several days.
  2. Add the dry ingredients and start mixing. If you're using a power mixer, turn it on to get the blades churning and gently add your dry ingredients. Be careful to not dump them and splatter the water out, or to lose too much of the cement by clouding it.
    • The order of ingredients isn't particularly important, but some mixers tend to add the cement first and the sand afterward if it isn't pre-mixed. It's generally just easier to break the bag on the mixer, dump it out, and shovel in the necessary amount of sand.
  3. Get your face out of the way, wear breathing protection, and don't breathe in any of the dust created, mortar mixes contain Silicates which can cause COPD, or other Cancers.
  4. Add extra water if necessary. As you mix, or as the mixer does its work, keep a close eye on the mortar. If it looks too dry, add small amounts of water as you go to keep it pliable and wet. Be careful about adding too much, and don't add too much right at the end, or you'll get a soupy, unintegrated, and useless mortar.

Mixing a Batch by Hand

  1. Make a pile of sand and place the appropriate number of cement bags on or right next to the pile. The pile should look like a small mountain.
  2. Cut open one side of the bag staving it with the blade of the shovel. Roll and pull the bag to empty the cement.
  3. Use a small shovel or hoe to work the mix around vigorously, making sure that the mix is distributed uniformly and even colored. If the mix is not evenly distributed the mortar won't have the right consistency.
  4. Form a crater with the shovel and pour the water inside. The water will begin to sink and soak through the mix.
  5. Use the shovel or hoe to pick the dry mix from the edges and throw it to the water in the center. Keep adding extra water as necessary to make sure it stays nice and wet. Mix thoroughly to distribute all the ingredients evenly.
  6. Let it mix for 3-5 minutes and let it sit another minute. Some brands like Quikrete call for a resting period to let the particulate get moist, making the mortar more effective. Transporting the mix into a wheelbarrow or buckets tends to take care of this resting period for you, though. It's important to not let it sit around too long or it will become stiff. Likewise, over-mixing tends to dry out the mix and decrease its working life.
    • A good way of checking the consistency is to "snap" the trowel. Scoop up some mortar on your laying trowel and flick your wrist downward to flatten it against the flat side of the trowel, then turn the trowel 90 degrees. If it stays without sliding off, you've got good mud.

Working with Mortar

  1. Start laying your block. Check for the right consistency and empty the mortar into a wheelbarrow or into individual buckets to lay out on a board and start using. Make sure everything is pre-wet, or you'll have some trouble with the mortar sticking to it. It should slide out easily, if you've done everything correctly.
  2. Always wear the proper safety gear when handling mortar. Getting dry concrete in your eyes, lungs, or on your hands can be very painful and dangerous. It's very important to wear gloves any time you're handling mortar, as well as safety glasses, and a face-mask when you're mixing up the dry cement. It can have a tendency to cloud up and get in your face, and is very hazardous to the lungs. Use caution and always equip yourself safely.
  3. Add a small amount of water periodically. Mortar dries quickly, which is partially why it's effective and so good to work with. You can lay courses as fast as you can keep up with it. Eventually, the mortar on your board will start to dry out some, so it's helpful to keep a small cup of water with you to drip a little on and mix up with your trowel to keep that good consistency.
    • Using overly-dry mortar will result in weak walls, which can especially be a problem if you're laying a foundation. It's important to keep the mix wet enough and workable enough to be effective.
  4. Never make more than you'll use in 2 hours. After an hour and a half or two hours, mortar tends to start to become too dry and unworkable, even if you add a tiny amount of water to what you're using. Plan out your work project carefully and only mix as much as you'll need for the job at hand. You won't be able to use it later.
    • When using lime and you are not as fast or it is your first time laying brick, try mixing smaller batches. Mix just enough mud to use within 45 - 60 minutes.
    • If you are able to get help, have someone mix and carry the mortar for you.
  5. Clean the mixer and all tools at the end of the day. At the end of a hard day of block-laying, you've still got an important job to do: knocking all the hard and dried mortar off the mixer, your boards, your wheelbarrows, and other tools. There are all sorts of different methods for doing this, but the most effective is also the most simple. Use a hammer to bang on your tools and collect the dry mortar to dispose of it properly.
    • Don't neglect cleaning your tools. Electric mixers especially can become bogged down if you haven't done a good job cleaning off the dried-up cement. There shouldn't be too much of it if you've been mixing properly, but there'll be some.
  6. It is always better to mix less and have to mix another small batch than having excess material harden on your tools or a big hard lump to pick up and dispose of.



Tips

  • When it is salty looking, it is often because it is "flash drying", which means that it is drying too fast. This weakens your work. Cover with wet sheets, rags and a tarp for a day or two to slow the process and increase the strength and the longevity of your work.

Warnings

  • Watch your eyes when dealing with sand, lime and cement as the dust from the dry cement and lime is extremely hazardous and the mixer can also spit out some of the mix when turning. Goggles are recommended.

Things You'll Need

  • Sand
  • Lime (hydraulic)
  • Cement
  • Water
  • Bucket
  • Cement Mixer

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Sources and Citations