Does stucco need an air gap?

Stucco and thin stone with continuous rigid insulation should take cues from EIFS—having an air gap to drain behind the rigid insulation is important, as moisture could potentially migrate there from the interior (as vapor) or from the exterior (in liquid or vapor form).

Is stucco an air barrier?

When detailed correctly at penetrations and transitions, stucco can function as an effective exterior air barrier.

Is stucco vapor permeable?

Because modern Portland-based stucco is not vapor-permeable and it traps moisture. Natural plasters, such as clay and lime, are much more permeable.

Does stucco need a drainage layer?

One-coat (synthetic) stucco over a cementitious backer board can work well, but it must have intentional drainage behind it. For traditional three-coat stucco, building codes often require two-layers of building paper behind the stucco.

Is stucco a weather barrier?

Three-coat stucco is the most common exterior cladding here in Southern California; properly installed, it's tough, durable, and attractive. But it's not waterproof. No matter how skilled the plasterer is, rain will get behind stucco.

WHAT is this, and WHY do you want it under your STUCCO?

What do you put behind stucco?

Because stucco is porous, the base—typically plywood or oriented-strand board sheathing—must have at least one layer of weather-resistant, vapor-permeable asphalt-impregnated building paper (“felt”) or plastic-based building wraps or stucco wraps. This barrier must reject weather and water but allow vapor to escape.

Should stucco touch the ground?

When installing stucco, you should ensure that it never touches the ground, or in other words, is below-grade. There needs to be a minimum of two inches of space between the concrete and the stucco for houses that rest on concrete foundations.

How does water get behind stucco?

Water may be getting behind the stucco through windows or other areas (possibly through improperly installed flashing). Some homeowners will deal with the mold at the surface and think that knocks the problem out.

How can you tell if water is behind stucco?

Stucco Siding and Water Leakage

You'll likely see staining around the corners of windows or doors, possibly dark spots where at the roofline, and even hairline cracks. All of these are indicators of possible water damage and are signs of where water runs on or behind the stucco.

Can you water seal stucco?

Any imperfection in the stucco or crack will allow water to seep in and start causing damage through the freezing cycle, mold, mildew and other moisture related problems. A great way to protect the look of your stucco and prolong the life of your exterior stucco is to apply a Stucco Sealer by Rainguard®.

What kind of paper goes behind stucco?

Under stucco, you can use asphalt felt or two layers of Grade-D building paper, commonly used on the West Coast. Both asphalt felt and Grade D paper will block liquid water but allow water vapor to pass through.

Are there different types of stucco?

There are two main types of stucco: traditional and synthetic.

• Traditional Stucco. Traditional stucco is comprised of sand, lime, and water. ...
• Synthetic Stucco. Unlike traditional stucco, synthetics does not use cement and lime. ...
• Float or Sand. ...
• Dash. ...
• Lace and Skip. ...
• English. ...
• Santa Barbara. ...
• Cat Face.

Can you stucco over plastic?

The best bond break between building paper and stucco, is, you guessed it, another layer of building paper (Figure 1). Similarly, a building paper bond break should be used between plastic building papers and stucco.

Can you put stucco on OSB?

Today's equivalent to that is cement block construction. But more often than not, stucco is applied today to homes which are made of standard wood construction, covered with plywood sheathing. Either softwood construction-grade exterior plywood can be used or OSB .

How often should stucco be sealed?

If new, stucco can be sealed with a clear concrete/ masonry sealer, which will penetrate into the stucco and stop moisture entrance. These are typically silicone type sealers. While effective, these finishes will usually need to be redone every 4-5 years.

What causes stucco to buckle?

Some of the most common causes for buckling stucco include: Water penetration due to poor installation. Thin spots in the stucco. Stucco isn't above grade.

What causes stucco to fall off?

When moisture does accumulate behind the stucco, it will soften any material it touches, which will cause the stucco to start breaking and falling off, sometimes in small quantities and other times in larger sheets.

What material is under stucco?

Sheathing is basically the “backing material” that can be found underneath the various layers of stucco that form the backing of residential and commercial buildings. They can be made out of wood, cement, gypsum, fiberglass and other materials.

How do you fix moisture in stucco?

If you believe the stucco requires a minor repair, you can remove the damaged section of stucco, much like you would with damaged drywall or rotted wood. Patch the area with a stucco mix that matches your current exterior. Apply three coats of the stucco and allow for drying time between applications.

Can water leak through stucco cracks?

Now stucco cracks don't always mean that there is damage, but it is usually a common sign of stucco moisture problems. Cracks and bubbles along the bottom edge of the wall — You may notice water leaking through the stucco walls and showing up along the bottom edge due to poor drainage systems.

How do you fill the gap between stucco and foundation?

Apply an elastomeric sealant or caulk between the foundation and the lower edge of the stucco. Completely fill the space between, making sure that the bottom of the backing board is covered as well. Use a caulk gun if necessary, although some sealants come in a tube that can be hand squeezed instead.

What is stucco weep screed?

Weep screed is a special piece of metal flashing that runs along the bottom of walls that wicks moisture out of holes that are located at the bottom of the flashing. It hangs below the lower sill plate to ensure that the water wicks past any material that could become damaged by excessive amounts of water.

Can you pour concrete up against stucco?

None. The concrete should slope away from home. If you have the option to go an inch down then fine so you don't mess up the stucco while pouring.