Patent Application
20170342709
The invention relates generally to exterior stucco wall constructions, for residential and business applications. More specifically, the invention pertains to an improved moisture drainage system that prevents waterproofing failure, mold, mildew, and wood rot, associated with conventional exterior stucco wall constructions.
In U.S. Pat. No. 6,355,333, granted to Waggoner et al., a Construction Membrane is taught. The membrane is described as resisting liquid and air penetration, being moisture vapor permeable, and being provided with integral drainage channels. The disclosed exterior wall construction which incorporates this membrane may be faced with stucco, siding, brick, or stone.
An Exterior Building Cladding Having Rigid Foam Layer With Drain Channels is shown in U.S. Pat. No. 6,886,301, granted to Schilger. Both the inside and the outside faces of the rigid foam insulation layer are provided with vertical channels 21 to remove moisture by way of thin channels 22. (See, FIGS. 3 and 4). Exterior water penetration drains to the bottom of channels 22, and exits the wall construction by means of a drain wick 28 and flashing 25.
In Published Patent Application No. US 2011/0296781, owned by McCary, an Insulating Finishable Panel is illustrated. This construction employs a rigid faced foam cored panel, which in one embodiment includes foam air spacers 15 adhered to the panel's radiant reflective surface 14. As in shown in FIG. 2, an air space 18 is thereby provided. In another arrangement, attached foam air spacers 32 create an air space 33 between the insulation 34 and the radiant reflective surface 14.
In Published Patent Application No. US 2008/0034690, owned by Gartz et al., an Underlayment With Improved Drainage is disclosed. The underlayment may include a plurality of vertical channels, 215 and 235, and funnels 370 and 371, at respective top and bottom edges. The funnels are provided to compensate for misalignment of vertically stacked underlayment panels.
Notwithstanding coats of paint and moisture sealant applied to the exterior layer of a stucco wall, moisture still manages to penetrate the stucco over time, and collect on layers of material within the wall. Known prior art construction methods provide moisture barriers and attempt to allow the drainage of accumulated moisture. However, these methods have proven inadequate, and stucco walls continue to fail from moisture intrusion and accumulation, allowing mold to form and causing wood to rot. The exterior stucco wall construction disclosed herein, provides improved drainage of the moisture which has penetrated the wall and collects therein on materials and structures. Improved longevity and integrity of the stucco wall system is thereby provided.
The exterior stucco wall construction disclosed herein comprises a wall frame, typically including a horizontal sill plate and a plurality of upstanding wall studs. A layer of sheathing is attached to the outer side of the wall frame. The sheathing includes a lower margin extending past the sill plate and over an upper outer edge portion of the supporting slab foundation.
An elongated moisture collection channel is provided. The moisture collection channel has an inner flange attached to the sheathing along its lower margin. The channel also includes an outer flange and a support floor extending between the inner flange and the outer flange. The support floor includes a plurality of apertures extending therethrough, with the apertures being arranged in spaced relation adjacent and along the inner flange of the channel. Preferably, the apertures are elongated, having coincident axes parallel to the inner flange.
A vapor barrier is attached to the outer surface of the sheathing to prevent moisture intrusion. The vapor barrier has a lower portion extending over at least a part of the inner flange, so that any moisture collected on or flowing downwardly on the moisture barrier will be directed into the channel.
A moisture impervious board, preferably manufactured from foam, has an inner side, an outer side, and a lower edge. The inner side of the board comprises a plurality of vertical channels for the downward drainage of moisture. These vertical channels may be defined by undulations in the surface of the inner side. The thickness of the board is defined by the distance between the inner side and the outer side of the board. This thickness is selected to be less than the distance between the inner flange and the outer flange of the collection channel, so that the lower edge of the board can be inserted and located within the collection channel.
Lath wire or its equivalent, is secured over the outer side of the moisture impervious board. At least one coat of stucco is applied over the lath wire and board. Preferably, a first inner coat is applied, known as a brown coat. The brown coat extends into the collection channel, effectively filling the volume between the outer side of the board and the outer flange of the collection channel. Then, a second outer coat is applied over the brown coat. This outer coat is commonly termed the finish coat, and it extends over the entire brown coat and the outer flange of the collection channel.
Turning now to the drawings, and in particular
A layer of sheathing 17 is attached to an outer side 18 of wall frame 12. Sheathing 17 has a lower margin 19, the lowermost edge thereof typically overlaps a small portion of foundation 16. Sheathing 17 is preferably made from sheets of plywood or OSB (Oriented Strand Board), but could also be comprised of individual pieces of lumber, with tongue and groove, shiplap, or abutting edges.
An elongated moisture collection channel 21 includes an inner flange 22, an outer flange 23, and a support floor 24 extending between inner flange 22 and outer flange 23. Inner flange 22 is attached to sheathing 17 along its lower margin 19 by means of conventional fasteners. Support floor 24 includes a plurality of apertures 26 extending therethrough, to allow the passage of moisture downwardly, through floor 24. Apertures 26 are strategically located, and arranged in spaced relation adjacent and along inner flange 22. Preferably, apertures 26 are elongated to maximize their efficiency in passing moisture, as will be explained below. The axes of apertures 26 are coincident, and parallel to inner flange 22, as shown in
A vapor barrier 28 is attached to the outer surface of the sheathing 17, as shown in
A moisture impervious board 31 is also provided. As shown in
By means of an upper tongue 36 located at the top of board 31, and a lower groove 37 located within lower edge 34, two or more boards 31 may be vertically stacked for additional height in the wall construction 11. This interlocking feature is illustrated in
The inner side 32 of board 31 comprises a plurality of vertical channels 38 for the downward drainage of moisture which has collected on inner side 32. Vertical channels 38 are defined by corresponding crests or undulations 39 on either side thereof. Channels 38 may also be straight walled cuts or recesses, but the curved channels are preferred as they are less likely to form stress cracks or break under stress. As is evident from
Between the inner side 32 and the outer side 33, a thickness for board 31 is defined. This thickness is less than the distance between the inner flange 22 and the outer flange 23 of the collection channel 21. This permits the lower edge 34 of board 31 to be located within the collection channel 21 during assembly of the wall construction 11. When board 31 is inserted within collection channel 21, the inner side 32 of board 31 is placed in contingent relation with vapor barrier 28 or with inner flange 22, in the event vapor barrier 28 does not extend to support floor 24. This ensures that the channels 38 will closely align with respective apertures 26 in support floor 24. (See,
This alignment feature between the channels 38 and the apertures 26 provides the maximum discharge of moisture and condensation, and the maximum flow of air to enhance evaporation of moisture and condensation, through apertures 26. As a final feature of this arrangement, the burrs 27 formed in the floor 24, effectively raise the lower edge 34 of board 31 slightly off the floor 24. This slightly spaced relation between the edge 34 and the floor 24, further enhances drainage and air flow in this region. It is apparent that spacing nubs or protrusions could be placed on the lower portions of edge 34, to provide the same effect. Or, discrete spacers could be placed on or formed into the floor 24 as an equivalent structure.
A lath wire 42 is secured over the outer side 33 of board 31, as shown in
It will be appreciated, then, that I have disclosed the features and structural details of an exterior stucco wall construction with improved moisture drainage.
