Local building officials should be consulted for further information about variations from the specified thickness. See www. In new construction, the structural system usually has more than enough strength to support installed plaster. In buildings that are being updated or retrofitted, however, stucco may be placed over existing construction. Concrete or masonry walls generally have sufficient structural strength to support the additional weight.
In wood frame construction, support members studs should be checked to ensure they can carry the extra load. A typical plaster mixture weighs about pounds per cubic foot, roughly the same as mortar, and this amount of material would cover about The metal lath may add a small additional amount of weight, so the end result is that three coat stucco weighs about For more information about the unit weight of plaster or installed weight, see Tables 1a and 1b on p.
The proper use of contraction joints in stucco systems will depend on a number of variables, including: the type of construction materials to which the stucco will be applied; the orientation of the construction—vertical walls or horizontal ceilings , and whether the surface is curved or angular.
Stucco may be direct applied to concrete or masonry substrates; however, if these materials are used together, as in the case of a concrete framework of beams and columns with masonry block infill, a joint may be required at the transition of one material to another.
Stucco that is direct applied to concrete or masonry requires contraction joints only where there is a change in material or where there are joints in the concrete or masonry structure. Metal lath may be used over concrete or masonry construction and should be used in sheathed frame and open frame construction. When stucco is applied to any construction using metal lath, joint spacing recommendations should be implemented. Applications that use metal lath require three layers of plaster: scratch, brown, and finish coats.
Currently, per the building code, a portland cement plaster is only required to have a weather resistant barrier WRB behind it, which is satisfied by the ICF; hence, building paper would not necessarily be required. Therefore, best practice indicates isolating the two materials from each other to allow independent movement and reduce stresses that might otherwise lead to cracking in the plaster layer. By using a permeable paper, the permeability of the wall system remains unchanged.
If it is desired to apply a finish directly to the foam form, an exterior insulation and finish system EIFS material may be considered. These finishes are thin, lightweight, and tough. Although the thinner exterior insulation and finish system materials can be direct-applied, moisture management then becomes even more critical. If an EIFS coating is chosen, openings windows, doors, etc. Stucco is known to be a weather resistant building finish, but it is part of a system.
In order for the wall to resist water penetration effectively, the system must be properly designed and detailed, then built according to plans.
The main purpose of building paper is to keep water from contacting the substrate and structural support members—very commonly sheathing like plywood or oriented strand board OSB and wood or metal studs—so that these materials stay dry. Metal can rust and wood can rot. Minimizing the changes in moisture minimizes the stresses that might be placed on plaster from behind.
In addition to structural considerations, excess moisture within a wall creates a potential for mold or mildew inside buildings. Building paper prevents moisture-related problems in stucco walls. During construction, paper can be damaged. Paper should be lapped like siding, meaning that upper layers are placed over lower layers. This facilitates drainage toward the outside.
Where the edges of paper-backed lath meet, connections should be lath-to-lath and paper-to-paper. This specification differentiates weather resistive Kraft papers by types, grades, and styles. Grade D is a water-vapor permeable paper. Grade D paper with a water resistance of 60 minutes or more works well for stucco applications, and is often preferred to Grade D paper having the minimum minute resistance required by UU-Ba. Some specifiers are turning to house wraps for stucco underlayment.
While these materials may be more rugged than paper—and therefore less prone to damage during installation—a single layer is still not adequate according to many industry professionals. At best, a hybrid system, with the house wrap closest to the sheathing and covered with the paper, seems to be an acceptable alternative.
For best performance, the temperature of newly applied stucco should be maintained at a minimum of 40 degrees Fahrenheit. In many cases, this can be achieved by heating the structure and covering the exterior surfaces. As temperatures drop lower, plaster ingredients can be heated before mixing the stucco. Both water and sand have enough mass to hold heat well, though it is often easiest to heat water.
However, either one, or both, materials can be heated to give plaster added protection in cold weather. To prevent problems like flash set of plaster, fresh mixtures should not be heated to temperatures exceeding degrees Fahrenheit. Most importantly, the stucco should not be allowed to freeze during the first 48 hours after placement.
Excess water in the fresh stucco mixture expands as it freezes, thereby compromising the strength and durability of the finished product. Sand can be heated over fire in a pipe, and water can be heated in metal drums.
Portland cement-based plaster, commonly called stucco, has long been and continues to be a popular choice for finishes on buildings. It allows for a wide expression of aesthetics, is a cost effective finish, is durable in all types of climates especially wet ones , and offers fire resistance. Fire resistance is typically classified by a fire rating, but what kind of fire rating does plaster provide? The type of member—wall, partition, ceiling, or other, and member classification load bearing LB or non-load bearing NLB also influences the rating.
Designers, specifiers, building code officials, contractors, and general public are the intended audience. For example, a typical residential application might be a three-coat system of plaster over 2-byinch wood studs using metal lath attached to the studs, either with or without a layer of sheathing, like plywood.
On the interior side would be a layer of gypsum board. The detail for a system made with these components is assigned a one-hour fire rating based on Uniform Building Code information. Association of the Wall and Ceiling Industry. Its mission is to be an active, unbiased source of information and education to support the wall and ceiling industry. The association is is located at W. Stucco can be painted. Portland cement-based paints are very compatible with stucco because they are made of the same material.
These paints should be scrubbed into the surface and fully cured. Alternatively, you could consider a colored stucco finish. These finish coats are often made with white cement and pigments, providing the widest range of colors.
Premixed materials are color matched from batch to batch and are most consistent. It is possible to paint with other types of paint, though these are usually not as long lasting as cement-based paint. Acrylic paints are long lasting and durable but change the permeability of the stucco make it non-breathable which in some climates may have adverse effects on the long-term performance of the system.
It is typically sprayed or rolled onto the surface, similar to painting with a cement-based paint. Fog coating improves the look of stucco without changing its ability to transmit moisture vapor. Stucco finishes are popular across North America. They lend themselves to nearly every type of architectural style.
Certain styles can be enhanced with built-out shapes, such as cornices, quoins, or decorative tiles. An expanded polystyrene foam section is bonded to the basecoat with a material made specifically for that purpose. Some people use an EIFS basecoat material as the glue.
This is attached to a portland cement plaster base, typically the brown and scratch coats, before final finishing. The shape is then finished like EIFS: covered with a basecoat and mesh, then a finish coat. The shapes must be securely attached to the wall. The basecoat material acts like a glue to hold the backside, then also embeds the mesh that goes over the top of the shape. As the foam itself has no structural strength, the mesh and basecoat together provide an impact-resistant surface to the shape, protecting it in service.
The Stucco Resource Guide from the Northwest Wall and Ceiling Bureau is one source of design and installation information for ornamental plaster shapes. It provides sample details of walls sections for creating architectural details on stucco walls. Whether you have some type of atmospheric contamination, biological growth, or staining from another construction process, stucco can be cleaned effectively.
Because it is important to choose an appropriate cleaning method based on what actually created the stain, there is no single best process for cleaning stucco surfaces. To clean a dirt-contaminated surface, the following advice is useful.
Stucco can be cleaned with a garden hose. Like concrete and masonry, stucco is porous. Cleaning methods are similar. It is recommended to wet the substrate starting from the bottom and working toward the top. Prewetting the surface helps the wall shed water, preventing dirty water from being drawn into dry pores. It also begins to loosen soil so that it can be rinsed away. A garden hose may be effective. Special fan-type sprayers are available for increased cleaning power. Whenever using water on a cement-based material like stucco, the substrate should have set and hardened.
Water under pressure can etch the surface and at higher pressures can even cut through hardened stucco. To prevent this, the water spray should be moved over the surface uniformly.
Most dirt is removed fairly easily. Cleaning power is increased by doing one or more of the following: increasing water temperature, scrubbing with a brush, or using some type of chemical detergent.
To clean stains other than simple soiled surfaces refer to the reference documents for additional recommendations. The Technical Service Information Bureau TSIB is a trade group in southern California serving the needs of the wall and ceiling industry regarding lath, plaster, and drywall. They have an excellent online resource depicting plaster textures.
The 30 textures shown on the site are accompanied by suggested application procedures. This gives material ingredient advice, where appropriate, and methods of applying or finishing the plaster to achieve specific appearances. Remember that sand will weigh a lot more than cement and a good trick would be to weigh half of a five gallon bucket of sand and cement, using an old bathroom scale and see how much each weighs.
After you have figured out the weight of each material, start by adding about a third of the sand to the bucket of water and mix for a few seconds.
Then, add all of your cement and mix again. Finally, add the rest of the sand and water if need be to achieve a moderately thick consistency.
Mixers are best for medium to large sized jobs and can pump out some serious square footage in one day, if you have the plasterers to match it. It is quite a workout though and will take a lot out of a novice at the end of the day or end of the project. Be sure to exercise extreme caution around these and never stick anything in the mixer while it is operating. Turn the mixer off first kill engine if you have to access the inside of the machine. First add some water roughly four gallons to start off and figure out how much of each material to add using a 3 to 1 ratio of sand 3 and cement 1.
Remember that sand will weigh a lot more than cement and you will be adding shovels to the mixer, roughly full shovels mounded up. Take a large shovel full of sand and place it on a scale to see how much it weighs and multiply it until it is roughly lbs. Once you have about 4 gallons of water in the mixer, add about shovels of sand to it, be sure to add a little more water if the mix is getting stiff. Next, add the bag of cement 94lbs. Finally, add the remaining sand to the mixer and add water until a stiffer mix is achieved.
Let it mix for about minutes and add little amounts of water until a desired consistency is achieved. My name is Ryan and I have been in the construction trades for many years now and I feel that there is a huge "knowledge gap" when it comes to particular trades I hope you find the information here useful. Thanks for stopping by! Save my name, email, and website in this browser for the next time I comment.
How To. Three Mixing Methods:. A Mortar Mixer. A Mixer: There are two different types of mixers, one that spins typically for concrete and one that has paddles that mix the cement called a paddle or mortar mixer. Barrel Type Mixer. A Bucket And Drill: This method is better for smaller applications and uses a 5 gallon bucket and a variable drill with a mixing attachment. Water: There is no rule to the amount you should add, but add it slowly until the consistency of pudding is reached.
If your sand is wet when you mix, then much less water will be needed, so there is no specific amount to utilize. It spreads easier and is more forgiving on the muscles and will not require you to add any lime to it.
Job-site finish coat: 1 part white portland cement or regular portland cement , parts lime, 3 parts sand. Raw color pigments — ASTM C; natural or synthetic iron oxides; variation in uniformity of color will be normal.
Hereof, how many bags of stucco do I need? Lay about 40 standard 8" x 8" x 16" block. Require bags for square feet of mass stone wall laying at a depth of 24".
Likewise, how much does it cost to stucco a sq ft house? To determine how many bags of concrete you will need , divide the total cubic yards needed by the yield. Use the following yields per each bag size: 40 pound bag yields. Using a Concrete Calculator You'll also get the number of pound, pound, or pound bags of concrete are needed for the project.
Asked by: Alberto Saenz De Viteri business and finance construction industry How many bags of stucco do I need per square foot? Last Updated: 22nd July, In most cases, a single five-pound bag will cover 30 square feet. In order to determine how many bags you will need for the job, divide the square footage of the surface by the square footage each bag will cover. In our example, we will need 3. Gnima Paulisch Professional. How much does a bag of stucco cover? Souraya Sueiras Professional.
What do you use for stucco? A standard cement, sand and lime mixture that works well, much like the Quikrete mix above.
Greencore stucco mix 80 lbs. Tanvir Berdun Professional. How much water do I need for a 60 pound bag of quikrete? Pour dry mix into the hole until it is approximately 3" - 4" 76 - mm from the top. Pour water into the dry mix until the powder is saturated with water.
Depending on soil conditions, this will require about 1 gallon 3. Bidatz Pitaevsky Explainer. How much is a bag of cement? Prices vary of course. Hudaifa Hoste Explainer. How much does an 80lb bag of quikrete cover?
Quikrete's Concrete Mix yield's about. Serafim Ebbing Explainer. How many 80lb bags of concrete make a yard? How many 80 lb bags of concrete do I need for 1 yard?
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