BACKGROUND OF INVENTION
- SUMMARY OF INVENTION
A common problem in wood frame structures is the accumulation of moisture within exterior walls and roofs due to migration of ambient moisture through the surface composition (e.g., stucco or shingles) or from inside the structure by condensation from interior air, where it can be absorbed by wooden structural members and other construction elements. The absorbed moisture can then lead to degradation of wall strength, odors inside the structure, and organism infestation that may be very expensive to correct. The present invention provides an inexpensive system and method of exterior wall construction that allows water to drain from the wall or roof before it is absorbed into the wood. It also provides a tool and method for providing drainage and drying means within a wall or under a roof.
BRIEF DESCRIPTION OF DRAWINGS
An object of the present invention is to provide an inexpensive system and method of wall construction that allows water to drain from inside a wall or from under a roof instead of being absorbed into the wood. Another object of the invention is to provide a tool and method for providing drainage and drying means in these locations.
FIG. 1 depicts a perspective cutaway view of a typical current system of exterior wall construction.
FIG. 2 is a perspective cutaway view of the preferred embodiment of the invention.
FIG. 3 is a perspective cutaway view of a typical insulated system of exterior wall construction.
FIG. 4 is an enlargement of the bottom of the wall in FIG. 2, showing a first means of preventing water from staining the exterior surface of the wall.
FIG. 5 is an enlargement of the bottom of the wall in FIG. 2, showing a second means of preventing water from staining the exterior surface of the wall.
FIG. 6 is a perspective cutaway view of a second embodiment of the invention.
FIG. 7 is a perspective view of the inner face and bottom edge of a portion of an insulating board shaped in accordance with the second embodiment of the invention.
FIG. 8 is a perspective view of a tool to be used to create a drainage layer in accordance with a third embodiment of the invention.
FIG. 9 is a perspective close-up view of the bit end of the tool of FIG. 8.
There are structural similarities between roofs and exterior walls in conventional wood frame dwellings. In walls, as explained below, the construction outward from the studs typically consists at least of wood (chip board or plywood) panels overlain with tar paper, which in turn is overlain with a surface composition such as lath-supported stucco. Roofs in their simplest form differ from this only in that they are not vertical, studs are called rafters, and the surface composition is shingles. For simplicity's sake, the descriptions that follow should be construed as applicable to roofs as well as walls in accordance with the above-noted similarities. The invention herein described is therefore not limited to walls. Referring now to the Figures, in which like numerals are used to depict like elements in all drawings, the present invention is described as follows:
FIG. 1 depicts a side cutaway view of a typical current system of exterior stucco wall construction. It comprises a layer of typically vertical and horizontal load bearing members represented in this figure by a vertical wooden stud 1 having an inner face 2 and an outer face 3. Inward of face 2 of the stud, and typically affixed thereto, are panels of gypsum wallboard 4. Affixed to face 3 is a panel 5, typically of chip board or plywood, covered by a sheet of felt paper 6. (Plastic “house wrap” sheeting is often substituted for the felt paper.) Affixed to the paper 6, in turn, by an fastening means 7, is a mortar support lath 8, typically made of expanded metal or plastic grid having holes 9. Applied in turn to the support lath 8 and into the holes 9 is a layer of stucco 10. Because the stucco and felt paper layers are never airtight, and because the stucco is typically exposed to the elements, moisture may collect between the panel 5 and the felt paper 6. Also, because of seams in the wallboard 4, the air inside the structure comes in contact with the wooden studs 1 and panels 5. During cold weather, these wooden parts may often be at a temperature below the dew point of the air inside the structure and thus may condense moisture from inside the structure onto their surfaces. Once inside the wall in liquid form, air circulation within the wall is so slight as to prevent the water from re-evaporating.
FIG. 2 depicts a side cutaway view of the preferred embodiment of the wall drainage system of the present invention as applied in stucco construction. It is comprises all the features of FIG. 1, and additionally comprises a substantially rigid and hydrophobic drainage layer 20 interposed between the paper 6 and the lath 8, a baffle 21 at the bottom of the wall, and weep holes 22 communicating between the layer 20 and the outside air. In the preferred embodiment, the layer 20 is comprised of shredded or chipped recycled tires. Any water 10 that penetrates the stucco will flow downward through the layer 20 under the influence of gravity until it reaches the baffle 21, where is it diverted to the outside through the weep holes 22.
FIG. 3 depicts a side cutaway view of a second typical current system of exterior stucco wall construction incorporating a layer of insulation. It comprises the typical layers represented, as in FIG. 1, by a vertical wooden stud 1, a chip board panel 5, and a sheet of felt paper 6. However in the insulated case, affixed to the paper 6, by fastening means 7, is an insulating board 30, typically polyisocyanurate foam. Attached to the insulating board 30 by a second fastening means 31, in turn, is the mortar support lath 8 having grid holes 9. Applied in turn to the support lath 8 and into the holes 9 is the stucco layer 10. With the insulating board 30 present, moisture is somewhat less likely to collect on the studs and panels from inside the structure than in the un-insulated case. This is because the insulating board prevents the studs and panels from getting quite as cold in winter and therefore they will not as often be below the dew point of the interior air. Nevertheless, appreciable moisture can get in over time. In addition, moisture is just as likely as in the un-insulated case to migrate to the outer surface of the insulating board through cracks in the stucco, and some of the moisture will inevitably find its way through seams in the insulation to the wooden parts. The insulation layer makes it even more difficult for collected water to re-evaporate and leave the wall.
FIG. 4 is an enlargement of the bottom of the wall in FIG. 2, showing a first means of preventing water from staining the exterior surface of the wall; the weep holes 22 may optionally be lined with non-porous tubes 40 that extend beyond the external face of the stucco 10 so as to isolate the water from the materials of the wall if desired and keep it from flowing down the face and staining it.
FIG. 5 is an enlargement of the bottom of the wall in FIG. 2, showing a second means of preventing water from staining the exterior surface of the wall; the baffle 21 may optionally be extended through the bottom of the weep holes 22 so as to form a lip 50 for the purpose of keeping water from flowing down the face and staining it.
FIG. 6 is a side cutaway view of a second embodiment of the present invention, similar to that shown in FIG. 2, in which hydrophobic layer 20 comprises insulating board having a notched face 60 and a notched bottom edge 61. The face 60 faces the outer surface of panel 5. The board would be typically sheets of dosed-cell expanded polymeric foam in which vertical notches and horizontal notches (see FIG. 7) are formed into face 60 and edge 61 respectively. This embodiment of the invention combines the water removal capabilities of the first embodiment with insulating properties.
FIG. 7 is a perspective view of the inner face and bottom edge of a portion of a hydrophobic layer 20 comprising insulating board shaped in accordance with the second embodiment of the invention. The vertical notches 62 provide the hydrophobic path for condensed water to flow under the influence of gravity to the baffle (not shown) and the horizontal notches 63 create weep holes 22 through this layer as described in FIG. 2.
FIG. 8 is a perspective view of a tool to be used to create a drainage layer between the panel and lath of the wall depicted in FIGS. 1 and 3 in accordance with a third embodiment of the invention. It comprises a flexible hollow snake 70 with a hand grip 71. Through the snake runs a tough wire 72 sized to rotate freely within the snake 70. At a first end 76 of the wire 72 a drive 73 is rigidly attached for insertion into the chuck of a suitable driver (not shown). At the second end 74 of the wire 72 is rigidly attached a shaped bit 75. A vacuum chamber 77 surrounds the wire 72 and pulls air in from second end 74 through annular passage 90. Any solids and liquids removed by bit 75 move through passage 90 into vacuum chamber 77 where they are filtered out of the air stream, which exits through outlet 78. A flexible boot 79 surrounds wire 72 near drive 73 to limit air in-leakage at that point. A cable 80 is attached to and runs the length of snake 70 carrying actuating cables for the steering mechanism and/or conductors for the moisture probe (both shown in the next figure). Other items (not shown) may be added to the side or top of the chamber 77 such as a sight glass to show the operator whether a significant amount of condensed water has been collected; a moisture probe readout; and/or control knobs for the steering mechanism.
FIG. 9 is a perspective view of the second end 74 of the tool of FIG. 8 while in use. With the driver attached to the first end (not shown) of wire 72 and running clockwise as viewed from the first end, bit 75 is rotating in the direction indicated by arrow C. The bit 75 is inserted through a pre-drilled diagonal hole between the stucco layer (not shown) and the panel 5. Due to the shape of the bit 75 and the direction of insertion into the wall, the bit preferentially seeks less resistive paths such as through the felt paper 6 in the interstice between the panel 5 and board 30 of FIG. 3. Due to its helical shape and due to manual pressure into the wall, the bit 75 will move forward and establish a drainage channel 81. Aiming of the bit 75 is accomplished by moving steering collar 86 on flexible struts 100 which are fixedly connected to both the collar 86 and the end of snake 70. This may be effected by the electronic or mechanical differential shortening of steering wires 82 and 83. By way of example and not limitation, if steering wire 82 comprises an electromechanical muscle wire that is shortened by the application of voltage, and voltage is applied to it, steering collar 86 will be pulled in the direction indicated by arrow I (into the page). Similarly, if steering wire 83 is shortened, steering collar 86 will be pulled in the direction indicated by arrow O (out of the page). The second end 74 may also comprise a moisture sensing probe 84 connected by cable 85 containing steering wire conductors 93 and 94 and moisture sensor conductors (not shown) to an operator's readout mounted near the first end of the tool (e.g., on the side of the vacuum chamber, not shown) to aid in directing the bit 75 toward high-moisture areas within the wall.
As the bit rotates and advances, it dislodges particles 91. The vacuum applied through annulus 90 by the vacuum chamber (not shown) pulls air into the wall along channel 81, where it picks up particles 91 and draws them into annulus 90 where they are removed from the wall. The relatively dry air entering the wall will also pick up moisture from the wall, so the vacuum may be left running for as long as necessary to dry the wall to a satisfactory level as detected by probe 84.