US2872882A - Vapor resisting roof structure - Google Patents

Description

Feb. 10, 1959 R; E. PAUL I ,87 ,8

VAPOR RESISTING ROOF STRUCTURE Filed May 13, 1954 INVENTOR. ROBERT E. PAUL BY J'' United States Patent VAPOR RESISTING ROOF STRUCTURE Robert E. Paul, Minneapolis, Minn., assignor to Minnesota and Ontario Paper Company, Minneapolis, Minn.

Application May 13, 1954, Serial No. 429,561

' 2 Claims. ('Cl. 108-6) This invention relates generally to thermo-insulation and resisters to the flow of water vapors and in particular to thermo-insulated water vapor resistant roof decks that provide a ceiling for the interior and a surface for receiving the roof structure. 7

The problem of heat insulation between atmospheric air volumes of different temperature is complicated by water vapor in the air and by the property of water vapor in air to condense at a precise temperature dependent. upon the water vapor content. It is important to prevent resulting damage to the roof insulating slab which furnishes the structural element of the roof and the decorative surface for the interior.

An important object of the invention is to provide a structural insulating unit adapted to take the place of roof boards now commonly in use and at the same time provide a ceiling for the interior of the structure and a roof receiving surface which may be safely used in an area where the average January isotherm is below 45 F.

A further object of the invention is to produce a specific type of structural insulating member which provides water vapor resisters on all edges, which vapor barriers cooperate with vapor barriers on adjacent units and which is shown and disclosed hereinafter.

For the purpose of this invention there has been elected to set forth certain particular structures but it is to be understood that they are here presented for illustrative purposes only and are not to be accorded any interpretation such as might have the efiect of limiting what is claimed as the invention short of its true and comprehensive scope in the art.

Other and further objects of the invention and the advantages of the same will be pointed out hereinafter and indicated in the appended claims or will be obvious to one skilled in the art upon understanding of the present disclosure.

The drawing forming a part of the specification where:

Figure 1 is a view in side elevation of two slabs in nonassembled position,

Figure 2 is a side elevational view of the two slabs shown in Figure 1 is assembled relationship,

Figure 3 is a side elevation view of the two slabs showing the longitudinal edge with the vapor barrier associated with the joint,

Figure 4 is a view similar to Figure 2 with a modified form of vapor barrier on the abutting edges, and

Figure 5 is a perspective view with parts broken away showing the vapor barrier along the edge and the end of the slabs.

An important feature of a roof slab made in accordance with this invention is that the roof goes up quickly and thus cuts the cost of construction. A roof made in accordance with this invention from the standpoint of comfort is effective in reducing heat transmission in either direction. A building employing a roof deck made in accordance with this invention will store up less heat in the summer which means cooler interiors during the day,

2 and a quicker cooling of the house at night. During cold winters it will result in the conservation of heat and thus reduce fuel costs. Before this invention a roof slab used to give a ceiling on one side and a roof receiving surface on the other could be used only in climates where the average January isotherm was not below about.

45 F. This was. due to the transmission of vapor into the roof structure. It was found that in climates experiencing freezing weather that vapor in heated houses migrated into the insulation and below the roof structure and as it acquired a lower temperature, due to the vapor condensing, it resulted in roofing difiiculties. Theoretically, condensation of vapors occurs at the dew point and at this point water is deposited such as causes difficulty particularly in built up roofs.

In the layer of a roof structure the longitudinal edges are fitted snugly together and the combination of the vapor resister along the edge in combination with the vapor barrier or resister placed adjacent the one side of the roof slab provides a substantially tight joint. Due to-the necessity of spacing the end joints of each unit about /s" apart, a vapor resister must be furnished at these joints. Although such joints occur over beams, sufficient vapor will leak through the joint to cause difficulty particularly in built up roofs. I Referring to the drawings in detail the roof slab indicated generally at 10 is composed of rigid fiber insulation board 12. Such board may consist of two or more laminations. To the rigid fiber board 12 is secured a ceiling layer 14. This layer furnishes the finished interior surface of the house. Between the board 12 and the layer 14 is vapor barrier 16. A suitable barrier is an asphalt saturated and coated paper, for example a 30-60-30 paper. To provide a suitable vapor barrier at the end of the unit which occurs over beams the vapor barrier 16 extends from the end not less than A" and preferably about 1 in. or more to provide free ends. Each roof slab is provided along the longitudinal edge with a tongue 22 and on the opposed edge with a groove 24. It is to be understood, of course, that various types of joints may be employed but regardless of the type of joint employed the grooves should be provided adjacent the tongue.

A suitable elastic gasket is preferred and a sponge rubber gasket by /2" has proven highly satisfactory. It is important that the gasket 26 in the assembled slab contact the barrier 16 of the slab in which it is positioned and the barrier in the adjacent slab. It is important that when the slabs are assembled that the gasket be tightly compressed. Generally, each roof slab is considerably longer than it is wide and it has been found that about 2 feet in width and about 8 feet in length gives very satisfactory results. In place of extending the vapor barrier 16 beyond the ends of the slab as shown in Figures 1 and 2, the ends may be formed together in overlapping joints as shown in Figure 4. If this type of joint is used, it is preferred that vapor barrier material be place in the joint as shown in Figure 4 at 28.

It is preferred that the ceiling portion of the slab be prefinished as by coating so that when applied a finished ceiling is provided. It is to be understood that the ceiling facing portion 14 may be of the same or of diiferent material to the portion 12.

The roof slab may be applied as follows: start the application at the lower edge of the roof and work up the slope; applying the units with the long dimensions at right angles to the framing members, leaving the tongue edge exposed; stagger the butt joint so that the adjacent piece does not end on the same framing member. It is necessary to bring the long edges together to a snug fit. To accomplish this it may be necessary to use a driving Patented Feb. 10, 1959 block against the upper shoulder of the joint above the tongue. It is important that the gasket 26 in the long joint be tightly compressed before the unit is secured in place. To insurethis result, each unit. should be placed. in position andbrought to a snugfit along the gasket edge and then immediately fasten the unit in place. The ends of the unit should be placed 4;" apart and when the adjacent units are in position a vapor barrier is provided at the ends as shown in Figure 2. It is not essential that calking material be used in the end joints but this joint may be calked after the slabs are in position as shown in Figure 2. It is to be understood that the built up roofs as well as other types may be used in connection with the present invention.

What is claimed:

1.. The roof deck assembly comprising the combination of exposed beams and a series of substantially rectangular insulating units secured thereto, each unit comprising a series of laminated fiberboard with a face board providing a finish ceiling surface, a vapor barrier membrane interposed between two layers of the fiberboard, saidmembrane having free-ends extending beyond the end edges and contacting the ends of spaced adjacent units and an elastic vapor barrier material positioned in a groove in the longitudinal edge of each unit and contacting the vapor barrier in adjacent units in the roof deck assembly.

. 2. A roof deck assembly comprising the combination of exposed beams and a series of substantially rectangular insulating units secured thereto, each unit comprising a plurality of laminated fiberboard with a face board providing a finish ceiling surface, a vapor barrier membrane interposed between the board providing the ceiling surface and the adjacent board, said vapor membrane having free-ends extending beyond the end edges and contacting the ends spaced adjacent units and a vapor barrier material positioned in a groove in the longitudinal edge of each unit and contacting the vapor barrier in adjacent units and the assembly roof deck.

References Qited in the file of this patent UN lTED STATES PATENTS OTHER REFERENCES Architectural Record, May 1954, pages 216-217.

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