Concrete roof deck ventilation ducts

Abstract

A roof construction method using expanded metal lath laid on top of corrugated metal roof deck for the purpose of creating ventilation ducts in the valleys of the corrugated metal deck. The ventilation ducts created are vented to the building space below through vent slots in the valleys of the metal roof deck. A concrete slab with finished rubber roof poured in top of this roof deck with ventilation ducts will have enhanced ability to release moisture trapped from the concrete curing process.

Claims

1. In a roof construction, in combination, a plurality of substantially rigid rectangular corrugated metal backing sheets, said sheets having a series of apertures formed therein, a plurality of expanded metal lath sheets layered on top of said backing sheets, said metal lath sheets having a series of apertures formed therein, said backing sheets and expanded metal lath joined together with self tapping screws at regular intervals, a layer of settable cementitious material on top of said sheets, said cementitious material bonding onto said expanded metal lath sheets and a waterproof finishing roof system covering said cementitious material.

2. The roof construction of claim 1 wherein the apertures formed in said backing sheets constitute approximately 1.5% of the surface area of the sheet.

3. The roof construction of claim 1 wherein the apertures in the corrugated metal backing sheets are v notches manually cut with a grinding wheel.

4. The roof construction of claim 1 wherein a plurality of twisted metal mesh sheets is substituted for a plurality of expanded metal lath sheets.

5. The roof construction of claim 1 wherein the finishing roof system is a continuous rubber roof over rigid insulation adhered to said cementitious material.

6. A method of constructing a roof comprising the steps of securing a plurality of substantially rigid corrugated sheets to horizontal roof joists, said sheets having a series of apertures formed in said backing sheets thereof and a plurality of expanded metal lath sheets covering and fastened to said backing sheets in substantially full contact therewith, pouring a layer of settable cementitious material on top of said sheets and said cementitious material bonding said metal lath sheets, allowing said cementitious material to set and harden, and covering said cementitious material with a waterproof finished roof system.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a plan view of corrugated metal roof deck layered with expanded metal lath to create mini ducts in the corrugations of the roof deck;

(2) FIG. 2 is a isometric sectional view showing a step-wise construction of the present invention according to an exemplary embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

(3) The following detailed description is of the best currently contemplated modes of carrying out exemplary embodiments of the invention. The description is not to be taken in a limiting sense, but is made merely for the purpose of illustrating the general principles of the invention, since the scope of the invention is best defined by the appended claims.

(4) Broadly, an embodiment of the present invention provides enhanced ventilation for removing excess moisture trapped in a concrete roof slab enclosed by rubber roofing above and corrugated roof deck below. Drying of the concrete slab is enhanced by increasing the area on the bottom of the concrete slab exposed directly to air flow to the building space below. This is accomplished by preventing the concrete slab from filling the valleys of corrugated metal roof deck and thus creating mini ducts between the concrete slab and the corrugated roof deck. The top of the mini ducts are formed with expanded metal lath. The lath has 70% or more of its area consisting of openings. The openings are small enough so that the concrete can penetrate into the openings but can not flow through the openings. Air flow enters the mini ducts through venting slots in the bottom of the corrugated roof deck or through vent holes manually cut into the valleys of the corrugated roof deck with an electric grinding wheel.

(5) Corrugated metal roof deck spans between and is attached to structural support members spaced apart in regular intervals. The corrugated metal roof deck comes manufactured with vent slots spaced evenly along the bottom of the valleys of the corrugated metal roof deck.

(6) Alternately, if the corrugated metal roof deck does not have vent slots, v shape notch vent holes can be manually cut into the sides of the valleys of the corrugated metal roof deck at regular spacing.

(7) Expanded metal lath is laid on top of the corrugated metal roof deck ribs for the entire length of the roof area. The expanded metal lath is fastened down to the corrugated metal roof deck at predetermined spacing with self tapping tek screws through the lath and into the corrugated metal roof.

(8) The concrete roof slab is poured on top of the corrugated metal roof deck with mini ducts formed in combination with the metal lath. Reinforcing steel is also placed as required by the designer.

(9) After the concrete slab partially cures, rigid insulation is adhered to the top of the concrete slab and the rubber roof is applied to the top of the rigid insulation. Moisture trapped in the concrete slab as it cures can dissipate into the building below through the venting system created as described above.

(10) Referring now to FIG. 1, roof deck 10, typically manufactured from galvanized gauge metal steel is rolled into a continuous sheet and is bent into a shape with regularly spaced valleys 11 and ribs 12. Expanded metal lath 20 is laid on top of the roof deck 10 resting on top of the ribs 12. The deck valleys 11 and lath 20 form mini air ducts 30 providing a space for ventilation.

(11) Referring now to FIG. 2, structural support members 80 are spaced at regular intervals. Multiple sheets of corrugated roof deck 10 manufactured with vent slots 15 at regular intervals along the bottom of the deck valleys 11 span between and are attached to structural support members 80.

(12) Multiple sheets of expanded metal lath 20 are laid on top of the ribs 12 of the corrugated roof deck 10 to form multiple mini air ducts 30. Expanded metal lath 20 is fastened to corrugated roof deck 10 with self tapping tek screws 50 at regular intervals as required to prevent movement as a concrete slab is poured on top of the assembly.

(13) Concrete slab 40 is poured in placed to a thickness as required by the designer. After the concrete slab 40 has cured long enough to accept adhesive of the rigid insulation 60 the roof assembly is completed with the addition of the rigid insulation 60 and the rubber roof 70.

(14) Alternatively, if the corrugated roof deck 10 is not manufactured with vent slots 15, vent holes 16 can be manually cut into deck 10 at regular intervals with a standard electric grinding wheel in a v shape notch by cutting a slot at 45 degrees perpendicular to the rib 12 then rotating the grinding wheel 90 degrees to cut a second slot that joins the first slot at the bottom of the valley 11.