Insulated Roof Structure

Abstract

A roof structure includes a plurality of parallel spaced elongated purlins, and metal roof panels are secured to the upper surfaces of the purlins. Elastically flexible insulation panels are installed after the roof panels are secured to the purlins and are supported adjacent the underneath surfaces of the roof panels by longitudinally extending cap members mounted on the purlins. The insulation panels may also be supported by insulation strips positioned adjacent the sides of the purlins.

Parent Case Text

RELATED APPLICATIONS

This application is a division of copending application Ser. No. 796,038, filed Feb. 3, 1969, now patent No. 3,513,614.

Description

BACKGROUND OF THE INVENTION

In the construction of a roof for a metal building, usually a plurality of laterally extending roof or wedge beams are supported at longitudinally spaced intervals defining a plurality of laterally extending bays each having a predetermined width, as for example, 18, 20 or 24 feet. A plurality of longitudinally extending purlins are mounted on the wedge beams and are spaced laterally at predetermined intervals, as for example, 5 feet. Usually, the purlins have a C-shaped or a Z-shaped cross-sectional configuration, and the ends of the lower flange of each purlin are rigidly secured to the adjacent wedge beams by suitable screws or rivets.

After the purlins are secured to the wedge beams, strips of insulation material are unrolled laterally across the purlins after which a plurality of overlapping ribbed metal roof panels are secured to the upper flanges of the purlins thereby compressing the insulation material between the underneath surfaces of the roof panels and the top surfaces of the purlins. If the day selected for installing the roof happens to be windy or gusty, there is considerable difficulty in positioning and retaining each strip of insulation material while the overlying metal roof panels are positioned and secured to the adjacent purlins by either screws or rivets. Moreover, it is necessary to handle alternately both metal roof panels and rolls of insulation material, usually resulting in considerable labor inefficiency in the assembly of the roof. Furthermore, it is not uncommon for the insulation material to sag between the purlins thereby presenting an undesirable appearance from within the building and also creating air spaces between the roof panels and the insulation material where humid air can collect and condense on the underneath surfaces of the metal roof panels.

SUMMARY OF THE INVENTION

The present invention is directed to an improved roof structure especially suited for metal buildings and which significantly increases the labor efficiency for assembling a roof by enabling the insulation panels to be installed after the roof panels are installed. Thus on days when the weather is clear and favorable for working outside, the metal roof panels can be installed, and the installation of the insulation panels can be delayed till a day when the weather is unfavorable for working outside. The roof structure of the invention also provides for retaining the insulation panels adjacent the underneath surface of the overlying roof panels so that there are no air spaces whereby moisture can condense on the underneath surfaces of the roof panels.

In accordance with one embodiment of the invention, an elongated channel-shaped cap member constructed of either metal or plastic is mounted on the upper flange of each purlin. Each cap member includes outwardly projecting and longitudinally extending coplanar flanges which provide support surfaces spaced under the roof panels by a predetermined distance. A strip of insulation material is attached to the upper surface of each cam member and is compressed when the metal roof panels are secured to the purlins by either screws or rivets.

After the roof panels are installed, a plurality of elastically flexible insulation panels are positioned between the purlins, and each insulation panel is flexed while opposite edge portions are inserted onto the support surfaces provided by the flanges of the adjacent cap members. Preferably, each insulation panel comprises a pad of fiberglass having one side covered by a sheet of decorative vinyl material which also serves as a vapor barrier. In accordance with another embodiment of the invention, the support surfaces for the insulation panels are provided by strips of insulation material which are positioned adjacent the sides of each purlin and are supported by a longitudinally extending trim member attached to the lower surface of the purlin.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a somewhat schematic vertical section of a building having a roof constructed in accordance with the invention;

FIG. 2 is an enlarged fragmentary section of the porttion of the roof indicated in FIG. 1;

FIG. 3 is a fragmentary perspective view of the roof portion shown in FIG. 2; and

FIG. 4 is a fragmentary section of a roof constructed in accordance with another embodiment of the invention;

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows a metal building which includes a series of laterally extending inverted U-shaped frames 10 each consisting of a pair of tapered wall columns 12 which are rigidly connected by tapered roof or wedge beams 14. The frames 10 are spaced at longitudinal intervals, as for example, 18 feet, 20 feet or 24 feet corresponding to the bay length desired. Horizontally extending girts 15 each having a Z-shaped cross-sectional configuration, are mounted on the columns 12 in vertically spaced relation and are preferably formed with prepunched holes for attaching vertical metal wall panels 16.

A plurality of longitudinally extending purlins 20 are mounted on the wedge beams 14 in parallel spaced relation and between longitudinally extending eave struts 21. Each purlin 20 extends the length of one bay and preferably has a Z-shaped cross-sectional configuration formed by a longitudinally extending upper flange 22 connected to a lower flange 23 by a web portion 24. The end portions of the lower flange 23 of each purlin 20 are secured to the supporting wedge beams 14 by either rivets or screws (not shown). A longitudinally extending rib portion 26 projects from each flange 22 and 23 in parallel spaced relation to the web portion 24. Each eave strut 21 has a C-shaped cross-sectional configuration and a height equal to that of the purlins 20.

An elongated cap member 35 is mounted on each purlin 20 and includes an inverted channel portion 36 and outwardly projecting longitudinally extending flanges 38 forming coplanar support surfaces 40. Preferably, the channel portion 36 of each cap member 35 includes a series of prepunched holes 41 which align with corresponding prepunched holes 42 formed within the upper flange portion 22 of the adjacent purlin 20. Similar cap members with only one flange 38 are mounted on the eave struts 21.

An elongated strip 45 of insulation material is secured to the upper surface of each cap member 35 by a suitable cement. Preferably, each strip 45 of insulation material is formed of fiberglass and has a minimum thickness of approximately 1 inch. A plurality of ribbed metal roof panels 50 are mounted on the purlins 20, and the edge portions of adjacent panels are overlapped to form a water tight seal therebetween. Preferably, each roof panel 50 has prepunched holes which align with the holes 41 and 42, and a series of rivets 52 secure the roof panels 50 to the purlins 20 compressing the insulation strips 45 between the underneath surfaces of the roof panels and the top surfaces of the purlin cap members 35. The metal roof panels 50 may also be secured to the purlins 20 by screws which are usually either of the self-drilling type or the self-tapping type.

A plurality of insulation panels 55 are positioned between the purlins 20 and opposite edge portions of each insulation panel 55 are supported by the surfaces 40 of the opposing adjacent flanges 38 which are spaced from the underneath surfaces of the roof panels 50 by a distance slightly less than the thickness of the insulation panels 55. Thus each insulation panel 55 is supported in firm contact with the underneath surface of the overlying roof panels 50 to avoid dead air spaces between the insulation panels 55 and the roof panels 50.

Each insulation panel 55 is formed by laminating a sheet of decorative vinyl 58 to a fiberglass pad 59 thereby producing a semi-rigid panel which is elastically flexible so that when the panel is folded and released, it will snap back to its original planar condition. One such insulation panel which provides satisfactory performance is produced by Johns-Manville and includes tongue and groove edge portions for forming the laterally extending unsupported joints between adjacent purlins 20 within each bay.

The elastic flexibility of each insulation panel 55 enables the panels to be installed after the roof panels 50 are secured to the purlins 20. That is, each roof insulation panel 55 is partially folded in the center while the opposite edge portions are inserted into the spaces defined between the flanges 38 of the adjacent purlin cap members 35 and the overlying roof panels 50. When the insulation panel 55 is released, it snaps into a position in firm contact with the underneath surface of the overlying roof panels.

Referring to FIG. 4 which shows another embodiment of the invention, the metal roof panels 50 are secured directly to the upper flanges 22 of the purlins 20 such as by the rivets 41 shown in FIG. 2. A plurality of insulation panels 55' are supported adjacent the underneath surfaces of the roof panels 50 by the edge support surfaces 40' of a pair of strips 65 of insulation material positioned adjacent opposite sides of each purlin 20. Preferably, each insulation panel 55' has a vinyl covering 58', and each strip 65 of insulation material has a similar vinyl covering 68 to provide a decorative appearance for the underneath side of the roof.

The insulation strips 65 are supported adjacent the sides of each purlin 20 by a decorative trim strip 70 having generally an inverted T-shaped cross-sectional configuration. Each trim strip 70 includes one flange portion 72 which extends adjacent the underneath surface of the lower flange 23 of the corresponding purlin 20 which supports one of the insulation strips 65. Another flange portion 72 of each trim strip 70 forms a support for the other insulation strip 65. A longitudinally extending rib or flange 74 projects upwardly from each flange portion 72 of each trim strip 70 and serves to retain the adjacent insulation strip 65. The trim strips 70 may be formed as either a plastic or a metal extrusion and are secured to the purlins 20 by longitudinally spaced rivets 75 or suitable screws.

From the drawing and the above description, it is apparent that a roof structure constructed in accordance with the present invention provides desirable features and advantages. As a primary advantage, the roof structure of the invention provides for installing the insulation panels 55 or 55' after the roof panels 50 are installed. Thus it is unnecessary to handle insulation panels and roof panels alternately or simultaneously while installing the roof, which is especially undesirable when the roof of the building is being installed on a windy or gusty day. Thus, the roof panels 50 can be efficiently installed on a day when the weather is favorable for working outside and the installation of the insulation panels 55 or 55' can be postponed until a day when the weather is not favorable such as a rainy, windy or snowy day.

The combination of the purlin cap members 35 and the elastically flexible insulation panels 55 also enables each insulation panel 55 to be installed in position adjacent the underneath surfaces of the overlying roof panels so that there is no air space where humid air can collect and condense on the underneath surface of the roof panels. The insulation strip 45 on each purlin cap member 35 has been found helpful in avoiding the condensation of moisture on the underneath surface of the flange 22 of each purlin 20.

In the embodiment shown in FIG. 4, each insulation panel 55' may be placed in position adjacent the underneath surfaces of the overlying roof panels 50 after which the supporting insulation strips 65 are placed in position adjacent the sides of the corresponding purlins 20. In addition, the vinyl coverings 58' on the insulation panels 55' cooperate with the vinyl coverings 68 on the insulation strips 65 and the trim strips 70 to provide the roof with a decorative inside appearance with the insulated purlins providing a beam-like effect.

While the forms of apparatus herein described constitute preferred embodiments of the invention, it is to be understood that the invention is not limited to these precise forms of apparatus, and that changes may be made therein without departing from the scope and spirit of the invention.

Claims

What is claimed is:

1. An improved roof structure for a building comprising a plurality of parallel spaced elongated purlins each having an upper surface, an elongated cap member mounted on said upper surface of each purlin and having longitudinally extending and outwardly projecting flanges, a plurality of substantially rigid roof panels extending over said purlins, fastener means securing said roof panels to said purlins, a plurality of semi-rigid insulation panels extending between said purlins, each of said panels including a pad of fiberglass insulation material and a flexible sheet of plastics material secured to the underneath surface of said pad, the opposite edge portions of each said insulation panel resting on said flanges of an adjacent pair of said purlins, the spacing between each said flanges and the overlying said roof panel being substantially the same as the thickness of the adjacent said insulation panel causing each said insulation panel to contact the underneath surface of the overlying said roof panel thereby avoiding a dead air space therebetween, each said insulation panel being elastically flexible to provide for partially folding each said insulation panel for inserting said opposite edge portions into the spaces defined between said flanges and the overlying said roof panel to facilitate assembly of said insulation panels from below said purlins after said roof panels are secured to said purlins, and a longitudinally extending strip of insulation material secured to the upper surface of each said cap member and engaging the overlying said roof panel.