How To Repair Flaking Stucco

Stuccoing a whole business firm requires skills that take years to larn, but stucco repairs are well inside the capabilities of a diligent novice. If you lot spend a few hours watching a stucco job in your neighborhood, you lot'll pick up useful pointers.

A Basic DESCRIPTION

Stucco is a cementitious mix applied in several layers to a wire-board base over forest-frame structure or to a masonry surface such as brick, block, or structural tile. Similar plaster, stucco is usually practical in three coats: (1) a base of operations (or scratch) coat approximately iii⁄8 in. thick, scored horizontally to help the adjacent coat adhere; (ii) a brownish coat about 3⁄8 in. thick; and (3) a terminate coat (called a dash glaze by old-timers) 1⁄8 in. thick. For repair piece of work and masonry-substrate piece of work, two-glaze stucco is mutual.

Stucco Details

The mix. The mix always contains portland cement and sand, but it varies according to the amount of lime, pigment, bonders, and other agents. Meet "Stucco Mixes", for standard mixes. The consistency of a mix is easy to recognize just difficult to describe. When you cut it with a shovel or a trowel, it should be stiff enough to retain the cutting mark yet loose enough so it slumps into a loose patty when dropped from a height of 1 ft. It should never exist runny.

Stucco Mixes

Stucco Mixes

The perfect stucco mix is strong enough to retain a trowel mark yet loose enough to slump into a loose patty when dropped from a meridian of 1 ft. This mason is using his trowel to load stucco mix onto his militarist, which he'll deport to the wall. With a trowel, he'll utilise the mix in sweeping motions.

Building paper. Stucco is non waterproof. In fact, unpainted stucco will absorb moisture and wick information technology to the building newspaper or sheathing underneath. E'er presume that moisture will be present under stucco, and apply your building paper accordingly.

Basically, you desire to cover the underlying capsule with two layers of building paper before attaching the metal lath. Two layers of Grade D building paper will satisfy nigh codes, simply you lot're better off with two layers of a fiberglass-reinforced newspaper such as Super Jumbo Tex lx Infinitesimal. Although 60-minute paper costs more, it's far more than durable. Typically, the stucco sticks to the first layer of paper, exposing it to repeated soakings until information technology largely disintegrates; the 2d layer is really the only water-resistant one, so yous desire it to be as durable equally possible.

Take intendance not to tear the existing paper around the edges of a patch. Constrict the new paper under the sometime at the top of the patch, overlapping one-time paper at the sides and bottom of the patch. If the one-time paper is non intact or the shape of the patch precludes an easy fit, use pieces of polymer-reinforced flashing strips equally "shingles," slipping them upward and under the existing stucco and paper and over the new. Caulk new paper to onetime at the edges to help keep h2o out.

Lath. Metal board reinforces stucco so information technology's less probable to crevice, and it also mechanically ties the stucco to the edifice. Board is a general term; information technology encompasses wire mesh or stucco netting (which looks like chicken wire) and expanded metal lath (heavy, wavy-textured sheets). When nailing upwardly wire mesh, utilize galvanized furring nails with a furring "button" that goes under the mesh. When you drive these nails in, yous pinch the wire mesh between the nail head and the button, creating a infinite behind the mesh into which the scratch coat oozes, hardens, and keys. Don't utilize aluminum nails because cement corrodes them. Utilize about 20 nails or staples per square thou of lath, spacing nails at least every 6 in. Overlap mesh at least two in. on vertical joints, and extend it around corners at to the lowest degree six in.

Expanded metallic lath is a thicker, stronger board used in situations requiring greater strength—for example, to cover soffits, where you're fighting gravity while applying stucco. That is, expanded metallic lath won't sag. Information technology typically comes in ii-ft. by 8-ft. sheets, is somewhat more work to install, and costs more than. Expanded metallic lath is stapled or nailed up; at that place'due south no need for furring nails because it's cocky-furring.

Base coat. Here's how to apply the base (scratch) coat:

Comprehend the capsule with building newspaper and attach the lath.
Found screed strips, which are guides for the stucco's final surface thickness. Screeds can be existing window edges, corner boards, or strips manufactured for this purpose.
Mix and trowel on a thick first coat, pressing it to the lath.
When the mud has fix somewhat, screed it (meaning get it to a relatively uniform thickness) using screed strips as thickness guides.
Fifty-fifty out the surface further with a wood- or rubber-surfaced float.
Press your fingertips lightly against the surface; when it is dry enough that your fingers no longer sink in, steel-trowel the surface. Steel troweling compacts the fabric, setting it well in the board and driving out air pockets.
Scratch the surface horizontally.

Brown coat. Installing the brown (second) coat requires the most skill, care, and time because this stage flattens the surface and builds up the stucco to within 1⁄8 in. of its last thickness.

Applying the brown (second) coat — Applying the dark-brown (second) coat takes a lot of skill. The mason starts with an irregular scratch glaze and builds it upwards until the surface is flat and within ane⁄viii in. of its concluding thickness.

To apply the brown glaze, trowel on the stucco, screed it to a relatively compatible thickness, float the surface further, and steel-trowel to amend the uniformity. And then roughen the surface slightly with a woods or rubber float. As the stucco sets upward, you lot will be able to work it more vigorously to accomplish an even, sanded texture that will allow the finish texture coat to grab and bail. Practise non get out the brown coat with a shine, hard-troweled surface. Otherwise, the finish coat won't stick well.

steel-trowel the surface — Later applying the rough, brown coat with a hand trowel, the mason steel-trowels the surface to make the thickness uniform and the surface relatively apartment. After the mortar sets, he'll rough upwardly the surface slightly with a woods- or safety-faced float.

Finish coat. The finish glaze is virtually ane⁄8 in. thick and textured to lucifer the rest of the building. When attempting to lucifer an existing texture, y'all may need to experiment. If at offset yous don't achieve a expert match, scrape off the mud and effort again until yous find a technique that works. Textures are discussed at the end of this stuccoing department.

Stucco trim. If doors or windows in stucco walls are cased with wood trim, flash head casings with flashing tape. Metal windows in stucco normally have no casing to dam up water and need no head flashing; metal windows commonly have an integral nailing flange that serves as flashing after being caulked. If y'all need to cut back stucco siding to repair rot or install a new window, install flashing record over the caput casing, and install polymer-reinforced flashing strips along the sides and under the sill.

Cut back stucco to replace and correctly flash windows. Hither, the roof leaked considering the corner of the window was too close to the roof, where a lazy roofer simply stopped the step-flashing. The replacement window won't be every bit tall, so its sill will be at least iv in. above the roof.

HELPFUL MATERIALS

The following materials are particularly useful for repair piece of work and are available from whatever masonry supplier.

Weep screed is a metal strip nailed to the base of outside walls, providing a directly edge to which you lot can screed stucco. Considering information technology is perforated, it allows moisture to "weep" or migrate free from the masonry surface, thus allowing it to dry out thoroughly afterward a rain. Cry screeds are an easy way to brand the lesser edge of stucco await crisp and make clean. And because the weight of the stucco flattens the screed down against the top of a foundation, the screed provides a positive seal confronting termites and other pests. Cry screed is also a expert solution for the oft rotted intersection of stucco walls and porch floors. Cry screed isn't hard to retrofit, but you'll need to cut away the base of operations of walls 6 in. to 9 in. high to flash the upper border of the screed strip properly.
Wire corners are preformed corners (also called corner aids) that tin can be fastened loosely over the wire lath with 6d galvanized nails. Set the corner to the finished border, taking intendance to proceed the line direct and either plumb or level.
Latex bonders resemble white wood glue. They are either painted into areas to be patched or mixed into batches of stucco and troweled onto walls. To ensure that the mixture is uniform, stir the bonder into h2o before mixing the liquid with the dry ingredients. To assist a patch adhere well, brush bonder full strength all around the edges of the hole or crack you'll fill with new stucco. Merely applying patch stucco without bonder creates a "cold joint," which is more likely to fracture.
Prepackaged stucco mix is helpful because it eliminates worry virtually correct proportions amidst sand, cement, and plasticizing agents. Yet, you need to add bonder to the mix.
Elastomeric finish coats for stucco are acrylic-based and then, unlike paints, they are more flexible, less likely to crack, and their porosity allows moisture to escape. They come in a bucket, premixed—typically with sand added to match stucco texture—and are available in a broad range of rich colors. Acrylic finish coats are somewhat more than expensive than a regular cementitious coat, but because they come up precolored, you won't have to hire a painter after the finish coat of stucco has been applied—so you can actually save some money.

PRO TIP: Two ways to reduce stucco shrinkage cracks: (one) Add nylon fiber to the scratch glaze. (2) After the top stucco coat has cured at least three weeks, paint it with an elastomeric paint, which flexes equally materials aggrandize and contract.

Color-coat pigment (likewise known equally LaHabra color or permanent color topcoat), is a cementitious finish coat available in a limited range of colors. Withal, precolored topcoats commonly aren't of much utilize to renovators because their limited colors aren't likely to match older colors on a house.
Masonry pigment and primer, which is brine-resistant, can be used on whatsoever new masonry surface. You should still wait at least two to three weeks for the stucco to "cool off" earlier painting it. (Follow the manufacturer'southward recommended expect times.) Use two coats of primer and two coats of finish pigment.

THE REPAIR

Before repairing damaged areas, first diagnose why the stucco failed. Then determine the extent of the damage past pressing your palms firmly on both sides of the pigsty or fissure. Springy areas should exist removed. Continue pressing until yous feel stucco that'southward solidly attached. When removing damaged areas, be deliberate and avoid disturbing surrounding intact stucco. Avoid damaging existing lath then you lot can adhere new lath to information technology. Too avert ripping the quondam building paper if possible. Safety note: Whether removing old stucco or mixing new, wear center protection, heavy leather gloves, and at least a paper dust mask.

Diagnosing Stucco Problems

Here are some common symptoms of stucco bug and their probable causes.

DIAGONAL CRACKS from the corners of door or window trim indicate a shifting foundation; phone call a structural engineer.

Crumbling STUCCO along the base of a wall suggests standing water and likely deterioration of the capsule. Cutting back the damaged surface area and install a cry screed so water can go out.

Big PATCHES FALLING OFF suggest faulty flashing, rotted sheathing, or lath that's insufficiently fastened. Note: If you lot run across a shiny surface beneath a section of stucco that roughshod off, the installer likely waited too long to utilise that coat, mistakenly letting the bounder dry out. In this case, roughen the surface with a chisel before applying new bonder and a stucco patch.

You tin use a hammer and a cold chisel to remove a small section of damaged stucco. Simply for larger jobs, rent an electric chipping hammer with a chisel flake. Important: The bit should only fracture the stucco, not cut through it. Ideally, the underlying wire mesh and building newspaper volition remain undamaged.

PRO TIP: A ragged border is easier to disguise than a direct line when applying repair stucco. So when using a hand chisel or a chipping hammer, make your fracture lines meander. A rough edge besides helps agree the patch in. For this reason, don't use a diamond blade in a circular-saw blade is too likely to cut through the wire mesh and the waterproofing membrane.

Allow's say you're removing stucco to expose a rotted mudsill. Using a chipping hammer, fracture the stucco surface in two roughly parallel lines. On the beginning pass, delineate the meridian of the stucco to be removed. So make a second laissez passer 6 in. lower. Basically, yous'll eventually demolish all the stucco below the top cutline and restucco it afterwards you supervene upon the mudsill. But if you carefully remove the top 6 in. of the damaged stucco, you'll preserve the wire mesh in that section, giving you something to tie the new mesh and stucco to.

Cut through the wire mesh exposed by the second pass, insert a pry bar under the stucco, and pry up to detach the stucco from the sheathing. Because the first laissez passer of the chipping hammer separates damaged stucco from intact stucco, prying up this 6-in. corridor of stucco will not disturb the solid areas above it.

Now the strenuous piece of work begins. Using a bricklayer's hammer or a beat-up framing hammer, carefully pulverize the corridor of pried-up stucco. Stucco is hard stuff, so whacking it in identify with a hammer is more likely to drive it into the wood sheathing than to pulverize it. Notwithstanding, if you pry up the stucco slightly, you tin can slide a hand sledge under information technology to serve as an anvil. So, betwixt a hammer and a hard identify, the stucco will shatter nicely.

To remove stubborn chunks of old stucco from the wire mesh, pry upward the mesh plenty to slide the head of a hand sledge underneath so it can serve as an anvil. Hammered stucco will then pulverize. Article of clothing center protection and a newspaper respirator mask.

After you've removed all onetime chunks of stucco, you'll have a 6-in.-wide section of unencumbered wire mesh and, ideally, a layer of largely intact building newspaper under that. Once you lot've replaced the rotted framing (and sheathing), insert new newspaper, necktie new mesh to the old—just twist the wire ends together—and nail both to the sheathing. At present yous're ready to apply the new scratch coat.

If only the cease coat is cracked, wire-brush and wet the chocolate-brown coat, use fresh bonding liquid, and trowel in a new end coat. But if the cracks are deeper, the techniques for repair are much the same every bit those for patches, except that you need to undercut the cracks. That is, apply a cold chisel to widen the bottom of each crack. This helps key in (hold) the new stucco. Chip away no more than than you must for a good mechanical attachment. So castor the prepared scissure well with bonding liquid.

TEXTURING AND FINISHING

To disguise new stucco patches, it'southward frequently necessary to friction match the texture of the surrounding wall. Before texturing the finish coat, steel-trowel it shine and let information technology set about a half hr—although the waiting fourth dimension depends on temperature and humidity. Cooler and more humid atmospheric condition delay drying. Stucco immune to cure slowly is far stronger than fast-cured stucco. So, afterward applying the finish coat, apply a hose set on a fine spray to go along the stucco damp for iii days. Here are descriptions of the four mutual textures:

Stippled. For this effect, yous'll demand condom gloves, an open up-jail cell sponge float like those used to spread grout in tiling, a five-gal. bucket, and lots of clean water. After dampening the sponge float, press it into the partially set finish coat and chop-chop elevator the float straight back from the wall. Every bit you lift the float, it will elevator a bit of the stucco textile and create a stippled texture looking some-where between pebbly and pointy. Repeat this procedure over the unabridged surface of the patch, feathering it onto surrounding (erstwhile) areas also to blend the patch in. Rinse the float often. Otherwise, its cells volition pack with stucco, and the float won't heighten the desired little points when you lot lift it. Equally important, the sponge should exist damp and not wet. If you lot desire a grosser texture than the float provides, utilize a big open-jail cell natural sponge. If you notice that the new finish is pointier than the former surrounding stucco, that's probably because the old terminate has been softened by many layers of paint. To ameliorate the match, knock the new texture down a little by lightly skimming information technology with a steel trowel.

After completing repairs, texture the wall to alloy the patch to the surrounding stucco. Here, plastering cement, LaHabra color, and water were mixed repeatedly, poured into a hopper, then sprayed onto the wall to create a stippled effect. (This wait is also known as "spray dash.")

Swirled. Screed (level) the patch's finish coat to the surrounding areas, and plumage it in. After yous've made the patch fairly flat, comb it gently with a moisture, stiff-bristled brush. For best results, use a light touch and rinse oft; otherwise, you lot'll elevate globs of stucco out of the hole. By varying the pressure on the brush, you lot can change the texture.
Spanish stucco or skip troweled. This texture looks rather like flocks of amoebas or clouds. To reach this look, screed off the patch so it'southward but i⁄sixteen in. below the level of surrounding areas. Then, using a steel trowel, scoop small amounts of stucco off a mortarboard and, with a flick of the wrist, throw flecks at the wall. Skim the flecks with a swimming puddle trowel because its rounded edges are less likely to gouge the stucco equally y'all flatten the flecks slightly. As the trowel spreads the material, it skips over the sand particles, leaving flattened patches of texture and gaps.
Sand float is achieved by rubbing the concluding coat with a safety float. This creates an fifty-fifty, sandy texture that looks rather like suede—even from twenty ft. abroad. It'south a very popular texture.

Renovation 5th Edition