Tools and Materials

Modern masonry is durable, flexible and attractive. Here's what you should know before starting work.

ANYONE CAN work successfully with masonry materials and have fun doing it. It's true that a good size job can involve considerable labor, but with good planning the job—and the labor --can be stretched out over a period of time. A large concrete slab can be gridded (designed with a pattern of headers) so that the concrete can be mixed and poured in comparatively small batches that won't tax your patience or your strength. With brick and block faying you can stop any time and pick up again when you're re­freshed.

The flexibility of masonry materials adds considerably to the fun of working with them; you can be imaginative and creative. A concrete slab does not have to be a hot prairie playground; the surface is not limited to "smooth" or "rough"; the color is not limited to cement gray. Brick and masonry units, thanks to new develop­ments, are no longer prosaic, uninspiring building materials.

The truth about an amateur project is that the results can be every bit as good as a job done by a professional. Both in appearance and structurally, the job you do can rate A-l on the building inspec­tor's card. There will be a difference in time due to the fact that the pro can work faster, but the amateur need not worry about .speed—the end result is more important than the time needed to accomplish it.

A lovely setting and a lovely home (left photo). Masonry units used in construction deserve much of the credit for appearance of beautiful house.

Mixing in wheelbarrow is good system for amateur mason. A good batch can be mixed this way. and deep barrow easily contains the wet ingredients.

The mixture for concrete, actually an artificial stone, consists of a blend of fine and coarse aggregates, each piece of which is completely surrounded and held to its mates by hardened Portland cement paste. A chemical reaction, which occurs ideally due to favorable temperatures and the presence of moisture while curing, causes the paste to harden.

The most important rule is to be ready when the ready-mix truck arrives (see right). Have grad­ing done, forms in and friends around to help you.

Concrete mix lacking in finer particles will be hard to handle and place. It will be rough to finish and deep pours will have honeycombed surfaces.

Light troweling fills all spaces between coarse aggregates with finer particles with correctly proportioned mix. Such a workable mix also pro­duces most concrete for a given amount of cement.

Excess moisture will do this. Such a mixture will be plastic, easy to work and will produce smooth surfaces, but end product will be less durable.

The water to cement ratio is probably the most important factor as far as the strength of mix is concerned. Too much water will result in a thin, diluted cement-paste that will be weak and porous when it hardens. It will not bond the aggregates nor will it be watertight. The correct water-cement paste, and this is important, pro­duces a mix with maximum strength. The amateur will often use more water than necessary because it makes a more fluid mix that flows easily into the forms. Such a project may look O.K. to begin with (although there will probably be finishing problems due to excess moisture), but it will eventually be discovered to lack strength and durability.

Actually, too little water is much better than too much. The less water you use (and still come up with a workable mix), the stronger the mix will be! Ideally, the proportions suggested should be exactly followed by measuring precise quantities of perfectly dry aggregates. Since this is difficult to do under normal conditions, a good procedure to adopt, after aggregates and cement have been thoroughly mixed, is to add a small amount of water at a time (mixing as you go) until the concrete is pliable and yet can be compacted in your hand and placed so it will stand without crumbling. When a more fluid mix is re­quired add more water and more cement to keep a correct proportion.

Pour the concrete where it's most needed. If there's room available, truck can move from spot to spot. Spread and tamp pour with hoe or rake.

A shovel is also useful for spreading the con­crete mix. Note boots worm by workman—a good idea since you'll probably have to walk in pour.

Aggregates can be fine or coarse. Fine aggregate is usually sand although other materials may be substituted. The ideal sand for concrete contains particles that vary uniformly in size from very fine grit up to 4in. The gradation from fine to coarse is important because the finer par­ticles fill the spaces between the larger pieces.

Gravel, crushed stone, pebbles and slag are coarse aggregates that are a minimum of ¼ in. in size. As you can see, therefore, there is a constant gradation in aggregate size ranging from the very finest aggregates in the sand to the coarsest in the gravel. Larger sizes in coarse aggregate can go up CONCRETE FACTS to 11/2in. The kind of work for which the concrete will be used is a determining fac­tor—large aggregates are O.K. in heavy footings and thick foundation walls. A few rules to follow when determining aggregate size are given below:

General purpose concrete mix for walls, paths, steps, stones:
*.......... Portland Cement   one part
Sand            two and a quarter parts
Gravel (I in. max.) three parts
** Water    two-thirds part
*      One bag of cement equals 94 lbs. I cu. ft. in volume
** Water should be clean, good enough to drink—generally, use 5 gals, water per bag of cement
The following materials will make up I cu. yd. of concrete:
Portland Cement    6¼ bags
Sand .. 14 cu.ft.
Gravel 19 cu. ft.
Water . 31 ½ gals.

Concrete forms do not have to be pretty but do have to be sturdy. Note tie boards across front edges of boards that will form risers for steps; these keep concrete from bowing out the boards.

Wheelbarrow of wet concrete is not a light load. Make moving it as easy as possible by building plank roads up as close as possible to the site.

Wood floats are 12. 15 or 18 in. long and 3½ or 4½ in. wide. Hand float is used to prepare con­crete for troweling for smooth finish; the float alone is often enough for a good traction surface.

For walls—largest pieces should not exceed one fifth the thickness of a finished wall section.

For slabs—largest pieces should not exceed one third the slab thickness.

When pouring in confined space (foundation walls, for example)— largest pieces should not exceed three fourths of the width of the narrowest space through which the concrete must pass. This is figured on the basis of the average distance be­tween reinforcement steel or between the steel and the forms.

The reasoning behind the gradation of particle size in both fine and coarse aggre­gates is as follows: If all particles were large, a cross section of the pour would resemble a wall of Ping-pong balls. If, on the other hand, the cross section included marbles, beads, buckshot and BBs in ad­dition to Ping-pong balls, the smaller items would fill the spaces between the larger The cement paste, in addition to coating all the particles, would fill the most minute openings and the result would be a solid, dense mass with maximum strength.

After being taken from a natural source of supply, aggregates are screened, graded and mixed in proper proportion. Fine or coarse, all must be clean and free of all other matter. Any strange material in the mix (clay, loam, vegetable matter) will keep the cement paste from doing its job. If impurities are present the mix will be porous after hardening and have lower than standard strength values. The aggre­gates must be hard and durable if the concrete is to be likewise. If they are soft, flaky or at all soluble, they won't do a good job. The only exception is in lightweight con­crete mixes where porous aggregates are used to minimize weight.

Steel hand trowels range from 10 to 20 in. long and from 3 to 43/4 in. wide. Pro uses wide, long trowel for initial finishing, then switches to a shorter, narrower one for the last touches on a smooth surface.

Edger is used to produce radius along slab edges (left). This is done for appearance, to compact edge, reduce chances of damage. Tool comes in various sizes to produce radii from 1/8 to l½ in.

Below is a jointer or groover used to cut, finish joint. It can be used to improve appearance of contraction joints cut into a slab with a trowel.
 
All the ingredients described may be purchased separately or already mixed. Buying separately in bulk may be a good idea when you have a variety of projects that require different types of mixes, but where the projects are general—small walls, patio slabs, walks, etc.—it's a better idea to buy a "concrete mix", specifying the largest size aggregate you wish to have. This will be delivered dry (probably a 1 yd. minimum load) but with the proper pro­portions of fine and coarse aggregates thoroughly mixed. You add the cement and water.

For small jobs you can buy ready-mix products in sack containers. Some of these are 90-pounders (a cubic foot), others 60-pounders. Mortar mixes, concrete mixes, grout, pointing mortar, sand, gravel, stone -all may be purchased this way. But this is not the easiest or the most economical way to buy large quantities. Where you have a big slab to pour or a long walk, it's best to consider calling in a ready-mix truck. With this setup you get not only the aggregates, but the cement and water all thoroughly mixed and ready to pour when the truck arrives at the project site.

A level is an essential tool for checking, among other things, the height of form boards on op­posite sides of a pour—done here for a sidewalk.

Short-handled sledge is useful for pounding brac­ing stakes into ground. Those here are higher than forms, but will be cut off before the pour.

When the truck comes it will contain a lot of ready-to-pour concrete and the driver won't be happy about standing around for hours while you pick at the job. The ready-mix man is not going to dump a big oozy mass of concrete on your front door step and be on his way, but he will expect that you will be ready to receive the concrete, that you will have given thought to where you want the concrete placed and that you will have enough help on hand to efficiently unload the amount of concrete you have ordered in a reasonable amount of time.

Among other things, be sure the truck can get in close to the project site. If this is impossible, you'll have to use wheel­barrows. If you plan for the truck to travel over a driveway, be sure that the driveway will take the truck's weight. Sometimes it's possible to route a truck over a lawn, but be sure the ground is dry and that you plank the "road" with 2 x l2s at least.

Strike board is usually just straight piece of 2x4 long enough to span across pour so it can be zigzagged back and forth to level the concrete.

This may all sound a bit disturbing, but it shouldn't be. Just be sure you have a clear picture of what must be done and that you impose on a few friends to lend a hand. Once the pour is started you must see it through to the end, even if it means bring­ing out the floodlights. On big jobs, try to get an early start and be sure the truck gets there soon enough to give you plenty of time to go through all the necessary operations.

When mixing by hand you can make small batches in a wheelbarrow, larger amounts in a trough built for the purpose. You can also mix directly on the ground— in a driveway or on a level area of firm soil, for example. Building paper can be spread to protect the area and contain the mix.

The mix should be able to stand without sagging flat and without being slushy. Even the individual pieces of aggregate that may be on the surface of the mix should stay in place and should be thoroughly coated with the water-cement paste. This con­dition is the result of proper mixing as well as correct proportions.

That old evil of "too much water" can cause trouble here because it's quite likely that the bulk dry-mix materials you have contain a percentage of moisture. So, as we stated before, use less water than called for, mixing as you go and adding the maximum amount only if needed to produce a plastic, workable mix.

You can get a pretty good idea of how much moisture sand contains by picking up a handful and squeezing it tightly. If the sand falls easily between your fingers when you open your hand you can be pretty sure it is dry. If it holds its shape, you can be sure that it contains enough moisture to affect the amount of water needed for the mix. It never hurts to make a small trial mix, being especially careful to keep an accurate record of the amount of water used. You can judge from this how best to proceed.

A 10 gal. bucket, marked off to indicate quarts and gallons, can be used to measure water. A "bottomless" box with 12x12x12-in. inside dimensions can be used to meas­ure dry ingredients. Such a box will hold 1 cu. ft. of materials. Remember, too, that a sack of cement (weighing 94 lbs.) contains 1 cu. ft.—figure aggregates in like terms.

For many jobs, it is perfectly feasible to mix concrete by hand. This requires more labor than any other aspect of the job but it is a very important part of it. Mix in a wheelbarrow if the batch is small enough or work on a flat surface. A large sheet of waterproof plywood makes a good mixing platform but be sure to place it on a level surface; you don't want water running off since it will carry cement along with it. To make a permanent mixing trough add 2x6 or 2x8 sides and ends to the plywood, creat­ing a long, shallow box. This plus a metal lining is what they used to use in the "old days" but it's still a good tool to have around the house if you plan to mix con­crete for more than one small project.

Place the dry, measured materials onto the platform and mix them thoroughly. An amateur neglects this phase of the job; a professional doesn't. Mix until the whole batch assumes a uniform color. This will indicate that sand, gravel and cement have been blended together to the point where you can add water. Next, spread the materials to form a hole in the center into which you can pour water. Mix with a shovel or, better still, with a hoe. Be care­ful not to break the walls of the dam you created or you will lose water and, with it, precious cement. Stay with the mixing un­til all the aggregate is fully coated with the cement paste.

To lessen the chore of mixing for me­dium-size jobs, you can rent a small elec­tric mixer. These are available in a half-cement-bag size which will mix a large enough batch of concrete to satisfy any amateur. Some are hand-powered— you mix by turning a crank after you've put the materials in the barrel—but it's still less work to use one than hand mixing with hoe or shovel.

Be sure the job is fully prepared before you rent a mixer. There's no point in having it stand around while you work on forms or subbases. Be sure all materials are on land, forms complete, grading done. The same rules apply as for hand-mixing. Put dry materials in first and mix thoroughly, add water and let the machine run until you're satisfied that all aggregates are fully coated. The machine doesn't take too long to accomplish this—usually less than a minute. Sometimes you'll have to dump the mixer's load into a wheelbarrow and haul it to the site. When possible, situate the mixer so you can dump directly, sans the wheelbarrow labor detail.

Useful tools you can make yourself include a bot­tomless box with l2xl2xl2-in. inside dimensions for measuring dry concrete ingredients. Use ¾-in. plywood as shown in the drawing above. You can also make a simple, satisfactory wood float.

Pointing tools for block and brick are quite simi­lar. Many times, the amateur can do without by substituting a suitably shaped piece of hardwood or a length of small copper pipe bent up at one end (see right, above). Mason's hammer has one square face and one chisel prong. It's used to set the brick in place, cut it to fit if this is necessary.

Concrete should be placed as soon after mixing as possible. A short delay won't hurt much, but you're taking a chance if you wait more than 15 or 20 minutes. Spread the concrete just enough with a hoe or rake to work it into corners and angles. Tamp vertically with the rake to eliminate air bubbles and assure a dense mass. While some of this moving around is necessary, you should try to minimize it since excess working of the concrete will cause too much of the coarse aggregate to settle to the bottom. A gradation of aggre­gates should be uniformly spread through­out the pour in area as well as thickness.

Brick mortar (see photograph above) should be worked until it is very plastic and easily handled. Amateur should start by mixing in small batches.

Five-block lintel constructed with new Thread-line Mortar supports over 1,500 lbs. load with test setup (r.).· data in concrete block chapter.

When transporting concrete in a wheel­barrow, do it over a smooth surface even if you must place planks as a roadway. Ex­cessive bumping and knocking will cause the large aggregates to separate and settle. Pour where the material is most needed; overlap successive pourings. If you are fill­ing a high form, work around so you will be placing the concrete in layers from 6 to 12 in. thick. Don't fill in one place and then move to an adjacent area. High forms can be tapped with a hammer to settle the material inside. This usually guarantees a smooth wall when the forms are removed. A 2x4 used in a vertical motion will help settle and compact concrete in deep forms.

Concrete does not dry immediately; it sets because of a chemical reaction be­tween cement and water. Some authorities say that concrete will be strongest if, after setting, it is cured under water. This is not practical, but you can do much to increase strength by keeping the concrete wet for a number of days. Sprinkle it frequently with a garden hose. You can lessen this chore if you cover the pour with a layer of paper or burlap and wet the covering occa­sionally. Damp-cured concrete is stronger, by as much as 50 per cent, than concrete which is neglected after it is finished. Don't put a covering over it until it has set suffi­ciently, however. Otherwise you might mar the surface.

More facts on materials, tools, concrete and other masonry materials are covered in the following chapters.

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