Patent Application
20070130861
1. Field of the Invention
The present invention relates to building construction devices that provide drainage and reduce cracks within masonry coatings such as stucco. More specifically, the present invention relates to an improved movement control screed that is structured to operate as a control joint for absorbing movement in a masonry coating and also as a weep screed to provide drainage of water from within and behind the masonry coating.
2. Description of Related Art
Expansion control joints and foundation weep screeds are commonly known in the masonry construction arts.
The depicted foundation weep screed 70 is secured to the base of the plywood sheathing 56. The foundation weep screed 70 includes a flange 72, and a rib 75. The rib 75 defines an extending portion 74 for supporting an applied masonry coating and a returning portion 76. The extending portion of the rib 75 begins generally adjacent the foundation transition 61 and tapers downwardly as shown. A drip edge DE is defined between the extending and returning portions 74, 76 of the rib 75. Water resistant building paper 62 is typically positioned over the exterior wall 54 and the flange 72 for directing moisture from behind the masonry coating and over the foundation weep screed 70. Moisture can get behind the masonry coating at improperly sealed joints (e.g., at doors or windows) or because of cracks that may form in the masonry coating. If left unchecked, such moisture may cause rotting of wooden structures within the wall. Installation of foundation weep screeds 70 as described above create a moisture path extending down the building paper 62, along the flange 72, and over the extending portion 74 of the rib 75 to the drip edge DE as shown.
In the wake of severe storms such as hurricanes, many jurisdictions have modified their building codes to require significant reinforcement of first level exterior walls. Typically, this reinforcement is provided by constructing first level exterior walls from reinforced concrete or other similar materials. Such walls provide enhanced wind and impact resistance. However, building codes continue to allow upper floors and roof structures to be made from wood trusses that rest on top of the concrete reinforced exterior walls. In this regard, wall transitions are now defined between dissimilar wall materials (e.g., wood and concrete) used for upper and lower floors. Accordingly, it would be desirable to prevent moisture from entering such wall transitions. It would also be desirable to support masonry coatings applied above and below the wall transitions and to absorb movement of the masonry coatings such as might occur during curing or thermal expansion and contraction of the coatings.
The above needs and other advantages are met by a movement control screed that is structured for installation between first and second masonry coatings applied adjacent to a building wall and that functions both as an expansion control joint and as a weep screed. The movement control screed comprises first and second flanges and, in one embodiment, the first flange defines a planar substantially non-perforated surface for providing a moisture barrier and the second flange defines a substantially perforated surface that is adapted to more readily receive and support an applied masonry coating. At least two ribs defined between the flanges provide the ability for the flanges to move relative to each other and thus accommodate expansion, contraction, or other slight movements between adjoining wall sections. In addition, the ribs provide at least one drip edge to accommodate moisture drainage from behind a masonry coating and therefore the movement control screed also functions as a weep screed.
More specifically, a first rib defines a screed surface extending from the first flange adapted for positioning adjacent at least a portion of a first masonry coating and a second rib defines a screed surface extending from the second flange adapted for positioning adjacent at least a portion of a second masonry coating. In one embodiment, the first flange is deflectable from the second flange for supporting the first and second masonry coatings during relative movement. The screed surface of the first rib may also be deflectable relative to the screed surface of the second rib. Additionally, the screed surface of the first rib may be deflectable relative to the first flange and the screed surface of the second rib may be deflectable relative to the second flange. The above deflection capabilities operate to reduce cracking of the masonry coatings as will be apparent to one of ordinary skill in the art in view of the foregoing disclosure.
In another embodiment of the present invention, the first rib of the movement control screed defines a first screed depth that corresponds to a first masonry coating thickness and the second rib of the movement control screed defines a second screed depth that differs from the first screed depth and corresponds to a second masonry coating thickness. In one embodiment, the first screed depth is larger than the second screed depth. In this regard, first and second masonry coatings having differing thicknesses may be applied on either side of the movement control screed.
Another embodiment of the present invention is directed to a method of installing a movement control screed adjacent a building wall between first and second masonry coatings. The method includes attaching a movement control screed to the building wall wherein the movement control screed comprises a first flange, a second flange, a first rib defining a first screed depth disposed between the first and second flanges, and a second rib defining a second screed depth disposed between the first and second flanges. In one embodiment, the first screed depth is greater than the second screed depth. The method further includes a step of applying a first masonry coating to the building wall at a first masonry coating thickness that substantially corresponds to the first screed depth and applying a second masonry coating to the building wall at a second masonry coating thickness that substantially corresponds to the second screed depth.
The method may also include applying a water resistant layer over the first flange, before the step of applying the first masonry coating, in order to create a moisture path extending from the water resistant layer to the first flange and over the first rib. In addition, the method may include attaching a movement control screed having a first flange that is substantially non-perforated to encourage moisture to flow over and not behind the first flange. In yet another embodiment, the method may include attaching a movement control screed having a second flange that is substantially perforated to more readily receive and support the applied second masonry coating.
Having thus described the invention in general terms, reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and wherein:
The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all embodiments of the inventions are shown. Indeed, this invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Like numbers refer to like elements throughout.
For purposes of the foregoing specification and appended claims the term “masonry coating” refers to a surface covering for walls comprised of plaster, stucco, Portland cement, or other similar materials that are applied wet and then dry into a protective and/or aesthetically pleasing surface.
In the depicted embodiment, the first flange 132 of the movement control screed 120 is a substantially planar member that is arranged vertically against a building wall (not shown). The first flange 132 includes an attachment portion 133 and a substantially non-perforated portion 131. The depicted attachment portion 133 defines an aperture 136 for receiving an attaching fastener (not shown) or keying the position of the movement control screed 120 relative to an adjacent movement control screed (not shown) as will be apparent to one of ordinary skill in the art. One or more apertures 136 may be created within the attachment portion 133 during installation of the movement control screed 120 as one or more nails, screws, or other fasteners are used to secure the first flange to the building wall. The substantially non-perforated portion 131 of the first flange 132 operates as a moisture barrier as will be discussed in greater detail below.
The first rib 122 extends from the base of the first flange 132 as shown. In one embodiment, the first rib 122 comprises an extending member 121, a transition member R1, and a returning member 123. The extending member 121 defines a screed or engagement surface 121E that is structured to at least partially contact and support a masonry coating (not shown) when the masonry coating is applied. The first rib 122 can act as a screed to guide the application of the masonry coating when it is wet so that the resultant coating has the desired depth or thickness. After drying, the lower edge of the masonry coating may separate from the engagement surface 121E or the first rib 122 slightly, especially if there is significant contraction of the masonry coating, which can allow water to more readily weep from behind the masonry coating and over the first rib 122.
A drip angle θ is defined between the first flange 132 and the engagement surface 121E of the extending member 121. The drip angle θ is preferably greater than 90 degrees for encouraging moisture to run downwardly along the first flange 132 and on a descending path over the engagement surface 121E and transition member R1 of the first rib 122. In various embodiments, the drip angle θ is between 91 and 145 degrees, preferably between 92 and 120 degrees, and more preferably between 93 and 115 degrees. As will be apparent to one of ordinary skill in the art, providing such drip angles allows water behind the masonry coating to be drawn away from the building wall and to drip harmlessly over the transition member R1 of the first rib 122.
In the depicted embodiment, the second rib 126 is positioned immediately below the first rib 122 and above the second flange 134 as shown. The second rib includes an extending member 125, a transition member R2, and a returning member 127. Although the depicted transitions members R1, R2 define radii between the extending members 121, 125 and the returning members 123, 127 of the first and second ribs 122, 126 other non-radiused transitions are possible. For example, a chamfered, cornered, or pointed transition may be used especially in movement control screeds formed from polymeric materials.
A rib transition 128 is defined between the first rib 122 and the second rib 126. In the depicted embodiment, the rib transition 128 is a simply defined radius however, in additional embodiments, the rib transition 128 may include one or more flat or planar portions (not shown) for expanding a channel 150 defined between the first and second ribs 122, 126.
In various embodiments of the present invention, the returning portion 127 of the second rib defines an engagement surface 127E that is structured to at least partially contact and support a masonry coating (not shown). In the depicted embodiment, one or more anchor tabs 130 extend from the engagement surface 127E for further anchoring an adjacent masonry coating.
The depicted second flange 134 extends from the base of the returning portion 127 of the second rib 126 as shown. In one embodiment, the second flange 134 is at least partially perforated by apertures 138, 139. One or more of the apertures 139 may be structured to receive fasteners (not shown) for securing the second flange 134 to the wall. Other apertures 138 may be provided simply to define a non-continuous surface that is better adapted to support adhesion with an adjacent masonry coating. In other embodiments, various additional known techniques (e.g., etching, roughing, etc.) may be used to encourage adhesion between the second flange 134 and an adjacent masonry coating.
In various embodiments of the present invention, the first rib 122 defines a first screed depth A and the second rib 126 defines a second screed depth B. In the depicted embodiment, the first screed depth A is larger than the second screed depth B. In this regard, moisture running along the engagement surface 121E and over the transition portion R1 of the first rib 122 may be allowed to drip freely from the first rib 122 without impacting the second rib 126. Providing first and second ribs 122, 126 of differing screed depths may also provide additional benefits with regard to the application of masonry coatings having differing thicknesses as will be described in greater detail below.
Movement control screeds of various embodiments of the present invention may be manufactured from a variety of materials. For example, all or part of a movement control screed may be produced from metals such as aluminum, zinc, stainless steel, and galvanized steel, molded or extruded polymers and plastics, composites, and other similar materials. Factors influencing material selection are cost, corrosion resistance, regional or geographic environmental factors (e.g., expected humidity, environmental salinity, temperature, etc.), ease of forming, rigidity, and elasticity. The movement control screed depicted in
Movement control screeds 220 structured in accordance with various embodiments of the present invention may be installed adjacent a building wall 205 proximate the wall transition 215 defined between the masonry and non-masonry portions 210, 211. In the depicted embodiment, the movement control screed 220 comprises a first flange 232, a first rib 222, a second rib 226, and a second flange 234. The depicted first and second flanges 232, 234 are planar members positioned substantially flush against the non-masonry 211 and masonry 210 portions of the building wall 205, respectively. More particularly, the first flange 232 is secured to the plywood sheathing 216 of the non-masonry portion 211 of the building wall 205 by fasteners 260 such as nails, screws and the like. In one embodiment, the fasteners 260 are disposed generally through an attachment portion 233 of the first flange 232 thereby defining a substantially non-perforated portion 231 below the attachment portion 233 as shown.
One or more layers of water resistant building paper 212 may be provided over the building wall 205, the attachment portion 233 of the first flange 232, and at least a part of the substantially non-perforated portion 231 of the first flange 232 such that any water or moisture running down the building wall 205 drains over and not behind the first flange 232 of the movement control screed 220. In various embodiments, the movement control screed 220 is mounted such that at least part of the substantially non-perforated portion 231 of the first flange 232 extends a transition distance T below the wall transition 215 defined between the masonry and non-masonry portions 210, 211 of the building wall 205. In this regard, the non-perforated portion 231 of the first flange 232 provides a barrier that prevents moisture from entering the wall transition 215 and decaying or otherwise degrading the building wall 205.
The embodiment depicted in
A first masonry coating 245 is applied to the building wall 205 above the movement control screed 220. In one embodiment, a metal or plastic lath 213 may be applied over the relatively smooth surfaces of the building paper 212 and first flange 232 to support the first masonry coating 245. A second masonry coating 255 is applied to the building wall 205 below the movement control screed 220 as shown, and this coating may or may not be applied over lath (not shown) depending on the application. The second rib 226 includes an extending portion 225, a transition member R2, and a returning portion 227. The returning portion 227 of the second rib 226 includes a screed or engagement surface 227E that is structured to contact and support at least part of the second masonry coating 255 as shown. In the depicted embodiment, an anchor tab 230 extends from the engagement surface 227E of the returning portion 227 for anchoring the second masonry coating 255.
In various embodiments of the present invention, the screed depth of the first rib 222 operates as a guide or screed to define a thickness C for the first masonry coating 245. The screed depth of the second rib 226 operates as a guide for defining a thickness D for the second masonry coating 255. In one embodiment, for example, the first and second masonry coatings may be applied at thicknesses sufficient to define first and second outer masonry surfaces that align generally with the outermost points of the transitions members R1, R2 of the first and second ribs 222, 226 as shown. In other embodiments, the masonry coating may be applied at thicknesses sufficient to define first and second outer masonry surfaces that align generally with guide features defined by or disposed on the first and second ribs (not shown). Such guide features may include reference marks, protuberances, ribs, indentions, bends, or any other visible feature. Accordingly, the “screed depths” referred to in the present application and appending claims would be defined between the first and second flanges and such guide features rather than the first and second flanges and the outermost points of the first and second transition members as shown in
Conventional building codes allow masonry coatings applied adjacent walls of differing composition (e.g., wood reinforced portions vs. concrete reinforced portions) to have differing acceptable thicknesses. For example, the requisite coating thickness for masonry coatings applied to a reinforced cement wall or wall portion is less than the masonry coating thickness required for masonry coatings applied to wood framed walls or wall portions. Accordingly, in the depicted embodiment, the movement control screed 220 is structured to define a first masonry coating thickness C adjacent the non-masonry portion 211 of the building wall 205 that is greater than the second masonry coating thickness D defined adjacent the masonry portion 210 of the building wall 205.
As will be apparent to one of ordinary skill in the art, masonry coatings such as stucco or plaster have a measurable coefficient of thermal expansion. If such coatings are applied and rigidly confined, the resulting stresses may produce unsightly cracking. In addition, other factors might cause relative movement between the two sections of masonry coating, such as settling of the building or wind or temperature induced movements between dissimilar (e.g., cement reinforced vs. wood framed, etc.) wall portions. Accordingly, the first flange 232 of the movement control screed 220 may be deflectable from the second flange 234. The screed or engagement surface 221E of the first rib 222 may also be deflectable relative to the screed or engagement surface 227E of the second rib 226. Additionally, the engagement surface 221E of the first rib 222 may be deflectable relative to the first flange 232 and the engagement surface 227E of the second rib 226 may be deflectable from the second flange 234. The above deflections relieve slight relative movement (whether in the plane at the wall or otherwise) and the resulting masonry coating stresses occurring adjacent the wall transition 215.
Many modifications and other embodiments of the invention set forth herein will come to mind to one skilled in the art to which these inventions pertain having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the invention is not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.
