Stucco for Block Walls in Washington, UT | Washington Elite Stucco

What We Do

Block Walls We Finish

A block wall is stacked and mortared from CMU block, the concrete masonry units most people call cinder block, and concrete block stucco is the plaster finish laid straight onto that masonry. Four kinds of block wall turn up on properties around Washington, from the perimeter wall around a yard to the walls of the house itself, and each is bought for a different reason. All four take a finish. Which one you have changes how we prepare it, how many surfaces we cover and how easily we can reach them.

Perimeter and Privacy Walls

A perimeter wall rings a yard and carries nothing but itself, and built tall enough to block sight lines the same wall is a privacy wall. Freestanding means two faces, and both are usually finished. The top is a third exposed surface. Block is hollow, so a flat or open top lets rain run into the cells, while a wall cap or coping sheds that water and a drip edge throws it clear of the finished face.

We finish the gate posts too, along with the pilasters, which are the thicker columns built into the run, and the short returns where the wall turns a corner. Taller walls take longer to reach, so height changes the scaffolding we bring and the time on site. Most of these walls go up in raw gray fence block or split-face block, which looks unfinished beside a stuccoed house, and around a new build the wall itself is often there because the homeowners association required it.

Garden, Planter and Courtyard Walls

A garden wall or planter wall is low, and it holds soil against one face. That face stays damp, which changes what we do to the block before any plaster goes on, and drip emitters and irrigation lines usually run right against it. A courtyard wall or entry wall is the same work seen close up, where the float finish, the texture left by the trowel on the last coat, matters more than it does on a boundary run. We can also run cornices and other molded profiles along the top, and a short wall takes the same full coat build-up as a tall one.

Retaining Walls

A retaining wall holds a bank of earth back, so soil and water press against its hidden face year round. Stucco over cinder block does not drain a wall and does not waterproof one, so the weep holes through the face, the small drainage openings near its base, and the gravel behind it have to be working already; we check them, along with the top row of block and its cap, before quoting.

Only the exposed face is finished. One kind of wall we turn down: the dry-stacked interlocking blocks sold as segmental retaining systems. They are built to shift slightly and to shed water between the units, so plaster laid over them cracks along every joint. We will say so at the measurement.

Block Homes and Detached Structures

Many houses here are built of block rather than framed, a good number of them from the 1970s, and detached garages, shops and casitas are commonly block as well. Most of this work starts with an owner wanting a yard wall to match the block home behind it, or wanting both finished together in one color. What decides the method is what your wall is made of, not what it looks like from the street. A framed wall gets sheathing and lath before any plaster, which is a different job, and our stucco installation page covers it. Where an elevation is part block house and part framed, both methods go on the same building.

Preparing Block So Stucco Stays On It

On a framed wall, a crew builds the surface that holds the plaster. On a block wall that surface is already standing, so we condition the masonry instead of adding to it. How we prepare that masonry therefore decides how long the stucco lasts, more than anything we do afterwards.

Three questions settle the surface preparation for stucco over a block wall: what the block is made of and how it was laid, how much water it will pull out of fresh plaster, and whether anything on its face will stop the bond forming. The answers tell us whether the wall needs washing, dampening, a bonding agent brushed over it, or metal lath, and all of that is settled before the first batch is mixed.

Reading the Block You Have

Masonry does not all take plaster the same way, so we read the wall before we touch it. Gray CMU, older cinder block, split-face block with its broken stone-like front, slump block with its soft sagging courses, and the molded shapes sold as architectural block all differ in how rough and how dense their faces are, and that governs how firmly plaster keys into them. Split-face and other textured block offer more surface and grip well; dense block with a polished face is smoother and holds the bond less readily.

The mortar joints count too, because joints raked back leave a shallow ledge along every row of block for plaster to lock into, while joints finished flush with the face leave none.

Then there is whatever is on the face already: form oil left from casting the block, old paint, sealer, dust and any white salt bloom already on the face all sit between plaster and block, and pressure washing removes most of them.

One check you can make yourself settles most of what follows. Throw a cup of water at the wall and watch what the water does. Water that soaks straight into the face means bare, absorbent block: the straightforward case, and one we dampen before plastering. Water that beads and runs off means a coating is sealing the surface, and that wall gets lath instead. Water that sits there without soaking in means a dense face that needs roughening or a bonding agent first.

Controlling Suction in Desert Heat

Suction is the pull that dry masonry exerts on the water in fresh plaster. Cement needs that water to harden properly, and a block wall that draws it away too early leaves the coat weakest exactly where it meets the wall. Washington's desert climate makes that the main scheduling problem on a block wall. The stretch of days above 100F opens in the middle of June and runs into the first days of September, the humidity is low, and a dry wind takes moisture out of a fresh coat faster than sun alone. The trade counts a day as hot weather above 100F, or above 90F with wind over 8 miles an hour, and both are ordinary here.

So we dampen the block ahead of the crew until it is damp rather than running wet, keep the face being worked out of direct afternoon sun where the elevation allows it, and keep the applied coats moist, because curing needs water as much as mixing does. Heat also stretches the schedule between coats, and we let it.

From July into September we read the forecast before committing to a day, since a monsoon storm can wash fresh plaster off a wall, and at the cold end of the year we do not apply plaster below 40F ambient.

When Block Needs Lath Anyway

Some block cannot be plastered directly, and on those walls we fasten metal lath first. Painted or sealed block is the plainest case, because plaster applied over it holds the coating rather than the block, and the coating peels away in sheets and carries the finish with it. That failure is called delamination, and lath is what prevents it, giving the plaster a bond to steel rather than to paint. Block so smooth or dense that water beads on it raises the same problem in milder form, as do walls patched with block of a different density, where one area absorbs water and the next does not.

A wall that is part block and part framed gets lath across the whole face as well, so the two move as one plane instead of cracking along the line between them. ASTM C1063 is the preparation standard the code names for work of this kind, and it governs how the lath is fastened and held off the wall. Lath adds material and labor to a block wall, and we price a wall that needs it accordingly.

Prep, Scratch, Finish

Finishing a block wall runs from the first call to a wall that has fully hardened, and most of what decides how it looks in five years happens before any plaster touches the block. Washington Elite Stucco works through it in four steps.

1. We measure the wall. The visit costs you nothing, and the estimate that follows it is free. We measure both faces, then run the water test described above to read what the surface will do. We note the condition as we go: block that has crumbled or flaked at the surface, mortar joints that have failed, and any previous paint. We also look at how we reach the wall and where the crew can stand, since the height of the wall decides what staging we bring.
2. You get a written scope. Within 24 to 48 hours of the visit you have a written scope in hand. It names the plaster system going on your wall, how many coats it gets, which texture it is floated to and which color it is tinted, and it calls out metal lath anywhere the wall needs it, so that work is priced at the start rather than arriving later as a change to the bill.
3. Prep and damp down. On prep day we wash the wall down and take off loose material, old coatings and the white powdery bloom that comes out of masonry. Block that has flaked and mortar joints that have failed are repaired before anything is plastered, and lath goes on wherever the scope called for it. A bonding agent goes on where the surface needs extra grip. The block is dampened ahead of the crew. Your landscaping, drip lines and gates are covered and protected before the first bucket is mixed.
4. Scratch, finish and cure. The base coat goes on first and is scratched across while it is still soft, which is what gives the finish coat something to key into. The finish coat follows in the texture and color you approved, and gate posts and wall ends are finished at the same time so nothing is left half-done. Cement plaster hardens by staying wet rather than by drying out, so we keep the coats damp while they cure, and in summer heat that schedule stretches out. When the work is finished we clean the site and put your drip lines and landscaping back the way we found them.

To start with the measurement and the written scope, telephone (435) 319-6039 or describe the wall on the quote form.

What the Block Wall Underneath Decides

Stucco hardens onto the wall behind it and then follows that wall for the rest of its life, so the finish can only be as stable as what it is stuck to. A wall that shifts will carry the finish with it. Before we quote a block wall we look at two things: how the wall stands, and what condition its face is in.

Footing, Rebar and Movement

A block wall stands on a concrete footing poured in a trench below ground level, not on the soil itself. Vertical steel bars run up from that footing through hollow cells in the block, and the mason fills those cells with grout, a pourable concrete mix that locks the bars and the wall to the footing.

Where the footing is shallow or too narrow for the wall it carries, the soil under it swells and settles with the seasons and the wall moves a little each year. That movement concentrates at the weakest line through the masonry, which is usually the mortar between the blocks, and the finish over it opens on the same lines every year no matter how well it was applied.

So the survey covers how it stands: whether it leans, whether joints have opened, and whether cracks climb the wall in steps from block to block. We finish block walls, we do not build them, and if what we see is a wall that is coming apart underneath we tell you that and name what the wall needs first.

If the fix does call for digging, be aware that a trench alongside a wall in a finished yard routinely runs into gas, power, water and sprinkler lines, so we have the lines located and marked before anyone puts a shovel in.

Repairs That Come First

Whatever we find during that reading gets put right before any plaster goes on, because a repair made afterwards means cutting the new finish open again. We replace block that has crumbled or split at the face, or fill it back to a sound surface. A mortar joint that has gone soft is repointed, which means cutting the old mortar back and packing fresh mortar in, so the wall is solid across its whole face. Old paint and sealer come off, or, where they cannot be taken back to bare masonry, we specify lath over them instead.

Patched areas matter beyond their own strength: masonry that is denser or thirstier than the block around it pulls differently on the wet plaster and shows as a shadow through a thin finish, so the patching is brought to a consistent surface rather than merely filled. Restoring an existing stucco wall that has failed is a different job from finishing a bare block one, and our stucco repair page covers it. All of this condition work is priced as its own line, so you can see what is repair and what is finish.