Difference between revisions of "Stucco a House"
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== Steps == | == Steps == | ||
===Applying Stucco Over a Stud Wall=== | ===Applying Stucco Over a Stud Wall=== | ||
| − | #Check the weather forecast. The ideal weather conditions for applying stucco involve an overcast day with low wind, and temperatures of 50 to 60ºF (10–16ºC).<ref>http://www.askthebuilder.com/applying-stucco/</ref> Delay the job if the temperature is expected to drop below 40ºF (4ºC) or rise above 90ºF (32ºC) in the next week.<ref>http://www.cement.org/for-concrete-books-learning/materials-applications/stucco/stucco-frequently-asked-questions</ref> | + | #Check the weather forecast. The ideal weather conditions for applying stucco involve an overcast day with low wind, and temperatures of 50 to 60ºF (10–16ºC).<ref name="rf1">http://www.askthebuilder.com/applying-stucco/</ref> Delay the job if the temperature is expected to drop below 40ºF (4ºC) or rise above 90ºF (32ºC) in the next week.<ref name="rf2">http://www.cement.org/for-concrete-books-learning/materials-applications/stucco/stucco-frequently-asked-questions</ref> |
| − | #Put up sheathing materials. You may stucco over any rigid material attached to your support studs. The most common surfaces for stucco are plywood, oriented strand board (OSB), cement board, and exterior grade gypsum sheathing.<ref | + | #Put up sheathing materials. You may stucco over any rigid material attached to your support studs. The most common surfaces for stucco are plywood, oriented strand board (OSB), cement board, and exterior grade gypsum sheathing.<ref name="rf2" /> Make sure to follow local building codes while installing the sheathing material. |
| − | #*It is possible to stucco over an open frame, but this results in a less even and less structurally secure wall. If you plan to go this route, drive nails halfway into the studs, spaced out vertically in 5-6 inch (13-15 cm) intervals. String line wire horizontally along the protruding nails.<ref>http://www.free-ed.net/free-ed/Resources/Trades/carpentry/Building01/default.asp?iNum=1404</ref> | + | #*It is possible to stucco over an open frame, but this results in a less even and less structurally secure wall. If you plan to go this route, drive nails halfway into the studs, spaced out vertically in 5-6 inch (13-15 cm) intervals. String line wire horizontally along the protruding nails.<ref name="rf3">http://www.free-ed.net/free-ed/Resources/Trades/carpentry/Building01/default.asp?iNum=1404</ref> |
| − | #Cover the plywood with two layers of building paper. Most building codes require at least two layers of "Grade D" building paper or an equivalent water-resistant barrier.<ref>http://www.tsib.org/pdf/technical/60-216_Water-Resistive-Barrier-Physical-Properties.pdf</ref> You may use asphalt felt or some types of housewrap, but do not use a plastic housewrap not intended for stucco.<ref>http://www.greenbuildingadvisor.com/blogs/dept/musings/all-about-water-resistive-barriers</ref> Overlap the paper by at least 4 inches (10 cm) and fasten with roofing nails.<ref | + | #Cover the plywood with two layers of building paper. Most building codes require at least two layers of "Grade D" building paper or an equivalent water-resistant barrier.<ref name="rf4">http://www.tsib.org/pdf/technical/60-216_Water-Resistive-Barrier-Physical-Properties.pdf</ref> You may use asphalt felt or some types of housewrap, but do not use a plastic housewrap not intended for stucco.<ref name="rf5">http://www.greenbuildingadvisor.com/blogs/dept/musings/all-about-water-resistive-barriers</ref> Overlap the paper by at least 4 inches (10 cm) and fasten with roofing nails.<ref name="rf3" /> |
| − | #*While not required by most codes, an air gap between the two layers is highly recommended to prevent wall rot. A 3D plastic drainage mat between the two barriers is one way to accomplish this.<ref>http://www.greenbuildingadvisor.com/blogs/dept/musings/install-stucco-right-include-air-gap</ref> | + | #*While not required by most codes, an air gap between the two layers is highly recommended to prevent wall rot. A 3D plastic drainage mat between the two barriers is one way to accomplish this.<ref name="rf6">http://www.greenbuildingadvisor.com/blogs/dept/musings/install-stucco-right-include-air-gap</ref> |
| − | #Install weep screeds and casing bead. Install casing bead as a plaster stop at the corners of doors and windows.<ref>http://amico-lath.com/lath/casing_bead.htm</ref> Install weep screed at the base of the wall for better drainage.<ref>http://www.hometips.com/buying-guides/walls-siding-stucco.html</ref> | + | #Install weep screeds and casing bead. Install casing bead as a plaster stop at the corners of doors and windows.<ref name="rf7">http://amico-lath.com/lath/casing_bead.htm</ref> Install weep screed at the base of the wall for better drainage.<ref name="rf8">http://www.hometips.com/buying-guides/walls-siding-stucco.html</ref> |
| − | #*For this project, these two materials are not interchangeable.<ref>http://www.titanamerica.com/uploads/Common%20Errors%20in%20Lath%20and%20Accessories%202013-09-25.pdf</ref> | + | #*For this project, these two materials are not interchangeable.<ref name="rf9">http://www.titanamerica.com/uploads/Common%20Errors%20in%20Lath%20and%20Accessories%202013-09-25.pdf</ref> |
| − | #Attach metal lath. Selecting the correct lath and installing it properly is one of the more difficult parts of this project. Consulting a local contractor is recommended. In most cases, you should nail or staple the lath to the studs (not the sheathing) at no less than 7 inch (18 cm) intervals. Overlap the lath by at least ½" (1.25 cm) along the long side and 1 inch (2.5 cm) at the end, but not much more.<ref>http://www.awci.org/cd/pdfs/9612_c.pdf</ref> | + | #Attach metal lath. Selecting the correct lath and installing it properly is one of the more difficult parts of this project. Consulting a local contractor is recommended. In most cases, you should nail or staple the lath to the studs (not the sheathing) at no less than 7 inch (18 cm) intervals. Overlap the lath by at least ½" (1.25 cm) along the long side and 1 inch (2.5 cm) at the end, but not much more.<ref name="rf10">http://www.awci.org/cd/pdfs/9612_c.pdf</ref> |
| − | #*In all exterior stucco applications, you must use G-60 hot-dipped galvanized lath.<ref | + | #*In all exterior stucco applications, you must use G-60 hot-dipped galvanized lath.<ref name="rf10" /> |
| − | #*Choose lath with at least ¼" (6mm) furring, or make up for non-furred lath using furring strips or furring nails.<ref | + | #*Choose lath with at least ¼" (6mm) furring, or make up for non-furred lath using furring strips or furring nails.<ref name="rf9" /> Without this furring, the stucco will not adhere properly to the lath. |
| − | #Install control joints. To reduce cracking, divide the wall into rectangular panels using control joints, spacing them no more than 18 ft (5.5 m) apart. Also install control joints wherever two dissimilar walls meet.<ref>http://www.homedepot.com/catalog/pdfImages/0a/0afff321-4174-47da-96bc-768e2f52d66d.pdf</ref> If the lath is expanded metal (rather than stucco mesh), cut it behind each control joint to fully separate this rigid material into panels.<ref>http://www.stuccoguru.com/resources/article.cfm?articleID=B-04010&resourceID=4</ref> | + | #Install control joints. To reduce cracking, divide the wall into rectangular panels using control joints, spacing them no more than 18 ft (5.5 m) apart. Also install control joints wherever two dissimilar walls meet.<ref name="rf11">http://www.homedepot.com/catalog/pdfImages/0a/0afff321-4174-47da-96bc-768e2f52d66d.pdf</ref> If the lath is expanded metal (rather than stucco mesh), cut it behind each control joint to fully separate this rigid material into panels.<ref name="rf12">http://www.stuccoguru.com/resources/article.cfm?articleID=B-04010&resourceID=4</ref> |
| − | #*Make the panels as close to square as possible, and no larger than 144 ft<sup>2</sup> (13 m<sup>2</sup>).<ref>https://www.quikrete.com/AtHome/Video-Building-a-Stucco-Wall.asp</ref> | + | #*Make the panels as close to square as possible, and no larger than 144 ft<sup>2</sup> (13 m<sup>2</sup>).<ref name="rf13">https://www.quikrete.com/AtHome/Video-Building-a-Stucco-Wall.asp</ref> |
| − | #[[Mix-Cement|Mix the scratch coat]]. Mix the scratch coat from 1 part cement material and 2¼ to 4 parts plaster sand. If you are using Type I Portland cement instead of plastic cement, you'll need to add your own hydrated lime; count the final cement and lime mixture as the "1 part cement."<ref | + | #[[Mix-Cement|Mix the scratch coat]]. Mix the scratch coat from 1 part cement material and 2¼ to 4 parts plaster sand. If you are using Type I Portland cement instead of plastic cement, you'll need to add your own hydrated lime; count the final cement and lime mixture as the "1 part cement."<ref name="rf3" /><ref name="rf2" /> Mix with just enough potable water that you can trowel the stucco; any more, and it is likely to sage. |
#*The aggregate in the cement should be clean and well graded. | #*The aggregate in the cement should be clean and well graded. | ||
| − | #Trowel the scratch coat into the lath. Apply the scratch coat with a square trowel at a 45º angle, firmly pushing it into the lath. This layer should be ⅜" (9.5 mm) thick.<ref | + | #Trowel the scratch coat into the lath. Apply the scratch coat with a square trowel at a 45º angle, firmly pushing it into the lath. This layer should be ⅜" (9.5 mm) thick.<ref name="rf13" /> |
#*You may find it easier to use a hawk for some portions of the application. | #*You may find it easier to use a hawk for some portions of the application. | ||
#Score the scratch coat lightly. The first coat is called the "scratch coat" because of the shallow, horizontal lines scored into it by a notched trowel. This will ensure a good bond with the next coat. | #Score the scratch coat lightly. The first coat is called the "scratch coat" because of the shallow, horizontal lines scored into it by a notched trowel. This will ensure a good bond with the next coat. | ||
#Wet cure the scratch coat. When stuccoing over stud construction, the thick scratch coat must be allowed to cure for 48 hours. During this time, it is critical to protect the stucco from drying out. Mist or fog the stucco twice daily unless the relative humidity is above 70%. Protect the wall with a windscreen or sunshade if necessary. | #Wet cure the scratch coat. When stuccoing over stud construction, the thick scratch coat must be allowed to cure for 48 hours. During this time, it is critical to protect the stucco from drying out. Mist or fog the stucco twice daily unless the relative humidity is above 70%. Protect the wall with a windscreen or sunshade if necessary. | ||
| − | #Mix and apply the brown coat. Mix another batch using 1 part cement and 3 to 5 parts sand. Apply another ⅜" (9.5 mm) layer of stucco and screed to an even thickness, for a total thickness so far of ¾" (19 mm).<ref | + | #Mix and apply the brown coat. Mix another batch using 1 part cement and 3 to 5 parts sand. Apply another ⅜" (9.5 mm) layer of stucco and screed to an even thickness, for a total thickness so far of ¾" (19 mm).<ref name="rf3" /> Once the brown coat loses its sheen, float it smooth. |
#Wet cure for at least seven days. Wet cure as you did the scratch coat, but this time allow at least seven days. The first 48 hours are the most important, but you should continue to mist or fog it for this whole period, whenever it looks like it's about to dry. | #Wet cure for at least seven days. Wet cure as you did the scratch coat, but this time allow at least seven days. The first 48 hours are the most important, but you should continue to mist or fog it for this whole period, whenever it looks like it's about to dry. | ||
| − | #Cover with the finish coat. This final ⅛" (3 mm) layer determines the texture of your stucco wall.<ref | + | #Cover with the finish coat. This final ⅛" (3 mm) layer determines the texture of your stucco wall.<ref name="rf3" /> Apply and float it as you did the brown coat, but this time use 1 part cement to 1½ to 3 parts sand. You may purchase a finish which already contains pigment, or trowel on a plain finish and paint over it once it has had at least a week to cure. |
| − | #*Colored stucco finishes work best in pastel shades.<ref>http://www.tsib.org/pdf/plaster-assemblies-chapter-03-three-coat-plaster-stucco.pdf</ref> | + | #*Colored stucco finishes work best in pastel shades.<ref name="rf14">http://www.tsib.org/pdf/plaster-assemblies-chapter-03-three-coat-plaster-stucco.pdf</ref> |
#*If the finish is colored, wetting the surface during floating may cause mottling. A fog coat may make the color more even. | #*If the finish is colored, wetting the surface during floating may cause mottling. A fog coat may make the color more even. | ||
| − | #*Many decorative textures are possible when applying this final layer. Judge the appearance from at least 30 feet (9m) back before settling on a look.<ref | + | #*Many decorative textures are possible when applying this final layer. Judge the appearance from at least 30 feet (9m) back before settling on a look.<ref name="rf1" /> |
===Applying Stucco Over Concrete or Masonry=== | ===Applying Stucco Over Concrete or Masonry=== | ||
| − | #Prepare the wall's surface. You may apply stucco directly over these rigid, solid surfaces, but only if the surface is roughly textured and absorbent. If the wall does not absorb a sprinkle of water, or if there's obvious surface contamination, wash the surface thoroughly. If the wall is coated in paint or sealer, or if it's too smooth to support stucco, try one of the following treatments:<ref>http://www.cement.org/for-concrete-books-learning/materials-applications/stucco/stucco-installation-standards</ref> | + | #Prepare the wall's surface. You may apply stucco directly over these rigid, solid surfaces, but only if the surface is roughly textured and absorbent. If the wall does not absorb a sprinkle of water, or if there's obvious surface contamination, wash the surface thoroughly. If the wall is coated in paint or sealer, or if it's too smooth to support stucco, try one of the following treatments:<ref name="rf15">http://www.cement.org/for-concrete-books-learning/materials-applications/stucco/stucco-installation-standards</ref> |
#*[[Acid-Etch-Concrete|Acid etching]] | #*[[Acid-Etch-Concrete|Acid etching]] | ||
#*Sandblasting | #*Sandblasting | ||
| − | #*Bush hammer or roughing machine (for unpainted, smooth surfaces)<ref | + | #*Bush hammer or roughing machine (for unpainted, smooth surfaces)<ref name="rf3" /> |
| − | #*Applying a bonding agent, referring to specific product instructions. Do not use over water-soluble paint.<ref>http://www.awci.org/cd/pdfs/9310_a.pdf</ref> | + | #*Applying a bonding agent, referring to specific product instructions. Do not use over water-soluble paint.<ref name="rf16">http://www.awci.org/cd/pdfs/9310_a.pdf</ref> |
#*If there is any doubt that the wall can support the stucco, follow the instructions in the stud wall section above, attaching metal lath and plastering over it. | #*If there is any doubt that the wall can support the stucco, follow the instructions in the stud wall section above, attaching metal lath and plastering over it. | ||
| − | #Wet the surface. Wet the wall right before you apply the first coat of plaster, preferably with a fog spray. This improves the suction bond and reduces the amount of water the wall absorbs from the plaster, preventing premature drying. The surface should be damp, but not soaked.<ref | + | #Wet the surface. Wet the wall right before you apply the first coat of plaster, preferably with a fog spray. This improves the suction bond and reduces the amount of water the wall absorbs from the plaster, preventing premature drying. The surface should be damp, but not soaked.<ref name="rf3" /> |
#*Delay the job if the next week of weather involves freezing temperature, hot weather (above 90ºF / 32ºC), or high wind. These conditions will interfere with the curing process. | #*Delay the job if the next week of weather involves freezing temperature, hot weather (above 90ºF / 32ºC), or high wind. These conditions will interfere with the curing process. | ||
| − | #[[Mix-Cement|Mix the scratch coat]]. This coat should be 1 part cement material (including lime) and 2¼ to 4 parts sand.<ref | + | #[[Mix-Cement|Mix the scratch coat]]. This coat should be 1 part cement material (including lime) and 2¼ to 4 parts sand.<ref name="rf2" /> Plastic cement, which has been pre-mixed with lime, is usually the easiest to mix and work with. Combine this with plaster sand from a dry material yard.<ref name="rf17">http://www.stuccoguru.com/resources/article.cfm?articleID=A-01050&resourceID=3</ref> |
#*Only add enough water to allow you to trowel the plaster, or it may sag or fail to stick to the wall. | #*Only add enough water to allow you to trowel the plaster, or it may sag or fail to stick to the wall. | ||
| − | #Apply and score the scratch coat. Trowel on a layer ¼ inch (6.4 mm) thick.<ref>http://www.awci.org/cd/pdfs/9010_e.pdf</ref> Score this with shallow, horizontal lines using a notched trowel, keeping the tool perpendicular to the wall.<ref>http://www.stuccoguru.com/resources/article.cfm?articleID=A-01300&resourceID=3</ref> These grooves will help the next coat bond onto the surface. | + | #Apply and score the scratch coat. Trowel on a layer ¼ inch (6.4 mm) thick.<ref name="rf18">http://www.awci.org/cd/pdfs/9010_e.pdf</ref> Score this with shallow, horizontal lines using a notched trowel, keeping the tool perpendicular to the wall.<ref name="rf19">http://www.stuccoguru.com/resources/article.cfm?articleID=A-01300&resourceID=3</ref> These grooves will help the next coat bond onto the surface. |
| − | #*Acid-etched surfaces (among others) may not be quite rough enough for a strong bond with this method. Instead, dash on the scratch coat using a cement gun, or by whipping it on with a fiber brush or whisk broom. This forces out air to create a stronger bond.<ref | + | #*Acid-etched surfaces (among others) may not be quite rough enough for a strong bond with this method. Instead, dash on the scratch coat using a cement gun, or by whipping it on with a fiber brush or whisk broom. This forces out air to create a stronger bond.<ref name="rf3" /> |
| − | #*Some builders combine the scratch coat and brown coat into one base coat. If you choose to do this, plan on a total stucco thickness of about ⅜" (9.5 mm) for cast concrete, and ½" (12.7 mm) for unit masonry.<ref | + | #*Some builders combine the scratch coat and brown coat into one base coat. If you choose to do this, plan on a total stucco thickness of about ⅜" (9.5 mm) for cast concrete, and ½" (12.7 mm) for unit masonry.<ref name="rf2" /> Allow about ¼" (6.4 mm) of this thickness for the finish coat.<ref name="rf3" /> |
| − | #Apply the brown coat after a few hours. With modern cement on a rigid surface, there is no need to wait for the scratch coat to cure completely. For a stronger bond, trowel on the second, "brown" coat as soon as the scratch coat is rigid enough to resist cracking, usually after four or five hours.<ref | + | #Apply the brown coat after a few hours. With modern cement on a rigid surface, there is no need to wait for the scratch coat to cure completely. For a stronger bond, trowel on the second, "brown" coat as soon as the scratch coat is rigid enough to resist cracking, usually after four or five hours.<ref name="rf3" /><ref name="rf20">http://www.titanamerica.com/uploads/Double-back%20method%202013-09-20.pdf</ref> Rod and float this surface until it is level and ¼" (6.4 mm) thick.<ref name="rf18" /> |
| − | #*The brown coat mix should contain 1 part cement materials and 3 to 5 parts sand.<ref | + | #*The brown coat mix should contain 1 part cement materials and 3 to 5 parts sand.<ref name="rf2" /> |
#*It may help to compact this layer with a shingle float. | #*It may help to compact this layer with a shingle float. | ||
| − | #Keep the brown coat moist while it cures. Over the next 48 hours, it is critical to keep the stucco moist. If the [[Calculate-Humidity|relative humidity]] of the air is below 70%, you will need to mist or fog the surface once or twice a day.<ref | + | #Keep the brown coat moist while it cures. Over the next 48 hours, it is critical to keep the stucco moist. If the [[Calculate-Humidity|relative humidity]] of the air is below 70%, you will need to mist or fog the surface once or twice a day.<ref name="rf2" /> Wait at least seven days for the brown coat to cure, wetting periodically if it begins to dry prematurely. Some organizations recommend 10 or even up to 21 days of drying for even more crack resistance.<ref name="rf21">http://www.stuccoguru.com/resources/article.cfm?articleID=B-03055&resourceID=1</ref> |
#*In extremely hot or windy conditions, put up a windbreak and sun shade. You may even need to cover the moistened surface with polyethylene. | #*In extremely hot or windy conditions, put up a windbreak and sun shade. You may even need to cover the moistened surface with polyethylene. | ||
| − | #Put on the finish coat. The decorative finish coat contains 1 part cement materials and 1½ to 3 parts sand.<ref | + | #Put on the finish coat. The decorative finish coat contains 1 part cement materials and 1½ to 3 parts sand.<ref name="rf2" /> Optionally, it may include pigment as well to add color. Trowel and float this on in a thin layer, about ⅛" (3 mm) thick.<ref name="rf18" /> Allow it to cure completely before painting (if desired), following the same moist curing instructions above if the weather is hot. |
== Video == | == Video == | ||
