Flat roof with cover and hold down devices

Claim 2

A hold-down device for use in connection with a flexible elastomeric membrane covering a flat roof deck, comprising, in combination: (a) a disc having a domed, downwardly concave, middle portion and a contiguous, surrounding, substantially flat, transverse peripheral portion, the width of said peripheral portion radially of said disc being equal to between about 25% and about 50% of the radius of said disc as a whole, and said middle portion on its underside concavity being adapted to receive a quantity of a sealant, and (b) a screw or bolt-like fastener of a length' sufficient, when said disc is laid onto a membrane on a roof deck, to extend from said middle portion of said disc grippingly into the roof deck.

Claim 3

A hold-down device as claimed in claim 1, wherein the height of said domed middle portion of said each disc .above the plane of said peripheral portion is, at the highest part of said middle portion, equal to between about 15% and about 25% of the radius of said middle portion in the plane of said peripheral portion.

Claim 4

A hold-down device as claimed in claim 1 or 2, wherein said disc is made of metal, or of plastics material.

Claim 5

A hold-down device as claimed in any one of the preceding claims wherein said disc is provided with an aperture in said middle portion adapted to accommodate the shank of said screw- or bolt-like fastener.

Claim 6

A hold-down device as claimed in any one of the preceding claims, wherein said peripheral portion has its outer edge located slightly lower, with respect to said middle portion, than its inner edge.

Claim 7

A flat roof installation wherein a water-impervious sheet or membrane of elastomeric material is loosely laid flat on a roof deck, and a plurality of hold-down devices secure the membrane to the roof deck, the said hold-down devices including membrane-pressing members disposed on the membrane and screw- or bolt-like fasteners extending through said members and the membrane down into the roof deck; characterised in that: (a) each of said membrane-pressing members comprises a disc having a domed, downwardly concave, middle portion and a contiguous, surrounding, substantially flat, transverse peripheral portion the width of which radially of said disc is equal to between about 25% and about 50% of the radius of said disc as a whole, (b) a respective screw- or bolt-like fastener extends through said middle portion of each disc down into the roof deck and is tightened thereto and grippingly engaged therewith for securing said discs and thereby said membrane to said roof deck, (c) the concave underside of said middle portion of each disc is filled with a sealant compatible with the elastomeric material of said membrane, said sealant under each disc being pressed against said membrane, the respective fastener and the surrounding inner edge of the peripheral portion of that disc, and (d) said discs are distributed over the expanse of said membrane on said roof deck at predetermined spacings between each two adjacent discs in accordance with the sizes of said discs and the amount of hold-down force to be provided.

Claim 8

A flat roof installation wherein a water-impervious sheet or membrane of elastomeric material is loosely laid flat on a roof deck, and a plurality of hold-down devices secure the membrane to the roof deck, the said hold-down devices including membrane-pressing members disposed on the membrane and screw- or bolt-like fasteners extending through said members and the membrane down into the roof deck; characterised in that: (a) each of said membrane-pressing members comprises a disc having a domed, downwardly concave, middle portion and a contiguous, surrounding, substantially flat, transverse peripheral portion the width of which radially of said disc is equal to between about 25% and about 50% of the radius of said disc as a whole, (b) a respective screw- or bolt-like fastener extends through said middle portion of each disc down into the roof deck and is tightened thereto and grippingly engaged therewith for securing said discs and thereby said membrane to said roof deck, (c) the concave underside of said middle portion of each disc is filled with a sealant compatible with the elastomeric material of said membrane, said sealant under each disc being pressed against said membrane, the respective fastener and the surrounding inner edge of the peripheral portion of that disc, and (d) said discs are distributed over the expanse of said membrane on said roof deck at predetermined spacings between each two adjacent discs in accordance with the sizes of said discs and the amount of hold-down force to be provided.

Claim 9

A flat roof installation as claimed in claim 6 wherein the height of said middle portion of each disc above the plane of the associated peripheral portion is, at the highest part of that middle portion, equal to between about 15% and about 25% of the radius of said middle portion in the plane of said peripheral portion.

Claim 10

A flat roof installation as claimed in claim 6 or 7, wherein each disc is made of metal or of plastics material. N

Claim 11

A flat roof installation as claimed in any one of claims 6 to 8, wherein said sheet or membrane is made of either a non-porous or a closed-cell expanded elastomeric material.

Claim 12

A flat roof installation as claimed in any one of claims 6 to 9, wherein a respective gasket of elastomeric material is interposed between said peripheral portion of each disc and the underlying region of said membrane.

Claim 13

A flat roof installation as claimed in claim 10, wherein the elastomeric material of said gaskets when the same are initially installed is either wholly or partially uncured and thereafter cures in situ to become bonded to said discs and said membrane.

Claim 14

A flat roof installation as claimed in any one of claims 6 to 11, wherein said sealant is a urethane-based sealant.

Claim 15

A flat roof installation as claimed in any one of claims 6 to 12, wherein each disc is provided with an aperture in said middle portion adapted to accommodate the shank of the associated screw- or bolt-like fastener.

Claim 16

A flat roof installation as claimed in any one of claims 6 to 13, wherein said peripheral portion of each disc has its outer edge located slightly lower, with respect to said middle portion of that disc, than said inner edge of the same disc.