How To Repair A Bubbled Stucco Wall

At beginning glance, the seamless coat of stucco on the East Boston house looked as bulletproof as a sidewalk, the perfect foil against the harsh wet weather of this coastal city. Yet below its lush cloak of ivy, the cement shell was a mess of cracks and buckling, signs that water had gotten in and damaged the underlying woods lath.

When properly installed, stucco (a cement- or lime-based plaster) is about every bit carefree and long-lived a cladding as anyone could wish—100 years is non uncommon. But when big cracks or blisters appear, the time to make repairs is correct away, earlier the damage grows.

Antonio DiSilva of MJM Masonry performed the remedial work on the E Boston house over ten days, ripping off loose cloth and patching information technology with three split up coats. Here'south how to make stucco repair that lasts.

Stucco Recipes

Stucco Recipes

First coat:

ane⁄2 bag (47 lbs.) Portland cement
6 shovels brick or masonʼs sand, slightly damp
ane shovel hydrated lime
1⁄two cup acrylic bonding agent

Second and finish coats:

ane⁄2 bag (47 lbs.) portland cement
8 shovels aggregate sand for concrete
1 shovel hydrated lime
1⁄ii cup acrylic bonding agent

Directions:

Shovel the dry ingredients into a wheelbarrow and blend them with a mortar hoe.
Add the acrylic bonding amanuensis, so stir in water, a trivial at a time, until the mix reaches the consistency of buttercream frosting.
Too much water will make it loose and unworkable.
Once water is added, the mix will stay usable for 30 to xc minutes before it starts to harden.

Watch The Weather condition

Freezing temperatures can ruin wet stucco. Wait for nighttime temperatures that stay above 40 degrees before tackling repairs. Hot, dry, windy atmospheric condition tin also interfere by sucking out moisture the mix needs to cure properly. Work in the shade and so the stucco doesn't dry too fast. Between coats, keep the patch moist past covering information technology with a plastic sheet.

Work Safely

The alkalis in wet cement tin can cause burns. So when working with fresh stucco, habiliment gloves or touch on the mix only with your tools, non your fingers. Go on a bucket of h2o nearby to wash any splashes off your pare.

Finish It Right

No patch, no matter how expertly textured, volition match the color of the old stucco around it. To do that, you need to utilise a pigmented blanket over the entire surface. The patch at this house was covered with a thick, sprayed-on acrylic elastomer that bridges and seals hairline cracks. Other acceptable coatings include concrete paints and stains, mineral paints, lime washes, and "fog coats" of pigmented cement. Whichever coating yous utilise, make sure it's alkaline tolerant and permeable to water vapor. Otherwise, it will be peeling off in no time.

Steps for Repairing Stucco

Step ane: Intermission Off Loose Stucco

Whack information technology with a hammer, or a hammer and a cold chisel, taking care non to impairment the underlying wood lath supports. Center protection is a must.

Pace 2: Chip Abroad At The Edges

Go on until you accomplish stucco that's firmly adhered to its lath. Cut any metal mesh with snips.

Stride three: Encompass The Exposed Lath

Using a utility knife, trim a slice of course-D architect'southward newspaper to fit tightly forth the boundary where the old stucco meets the exposed woods board. Fasten the paper to the board with roofing nails, and so put a second layer of paper on meridian of the first.

Step 4: Add together Mesh

Identify galvanized metal lath over the paper and trim it tight against the edge of the stucco. Snips with outset handles volition make this job easier. Bulldoze more roofing nails through the mesh and into the wood lath.

Footstep 5: Mix The Stucco

Following the first-coat recipe, stir upward a batch of stucco, using a wheelbarrow every bit a mixing bowl. The acrylic bonding amanuensis added to this mix improves the adhesion of the new stucco to the old.

Step 6: Sling It

Wet the edge of the one-time stucco so it won't suck moisture out of the patch and weaken the bond between old and new. Scoop fist-size wads of wet stucco onto a brick trowel and toss them against the wire board until information technology'south completely covered. Smoothen the mix with a finishing trowel, so pack it against the edge of the existing stucco with a brick trowel. Proceed adding more material until this layer is near 1/2 inch below the existing stucco surface.

Footstep 7: Scratch It

When the patch loses its moisture sheen, score its surface to improve the bond to the next coat. Tape a plastic canvass over the patch to keep information technology from drying out.

Pace 8: Apply 2nd Glaze

Wait 7 days, then remove the plastic and mist the patch with h2o. Mix upwardly a batch of stucco following the second-coat recipe, and trowel on a 3/8-inch-thick coat, working from the lesser upwards. Pack down the edges with a brick trowel. Wait for the wet sheen to disappear, then trowel the patch smooth, simply below the level of the existing stucco. Cover again with a plastic sheet.

Step nine: Put On The Finish Coat

After iii days, remove the plastic, mist the patch, and mix up a fresh batch of stucco, following the stop-coat recipe. Unlike textures require different techniques. To match this wall'due south original "dash" finish, DiSilva scooped modest globs of wet mix onto his brick trowel, so flicked them against the wall until they were flush with the old surface.

Step 10: Wait To Paint

Let the patch cure for a calendar week before painting it and the rest of the wall. Under a coat of heavy-bodied acrylic elastomer, the patch is invisible.

Tools: