A hem used in a metal panel seam to reduce the potential for water migration
Tag: joints
Apron Flashing
a term used for a flashing located at the juncture of the top of a sloped roof and a vertical wall, chimney or steeper-sloped roof
Batten Seam
A metal panel profile attached to and formed around a beveled wood or metal batten.
Channel Flashing
In steep-slope roof construction, a type of flashing used at roof-to-wall junctures and other roof-to-vertical plane intersections where an internal gutter is needed to handle runoff. Commonly used with profile tile.
Combing Ridge
An installation of finishing slate or wood at the ridge of a roof whereby the slates on one side project beyond to the apex of the ridge.
Construction Joint
(1) a joint where two successive placements of concrete meet; (2) a separation provided in a building which allows its component parts to move with respect to each other.
Control Joint
A groove which is formed, sawed, or tooled in a concrete or masonry structure to regulate the location and amount of cracking and separation resulting from the dimensional change of different parts of the structure, thereby avoiding the development of high stresses.
Counterflashing
Formed metal or elastomeric sheeting secured on or into a wall, curb, pipe, rooftop unit or other surface, to cover and protect the upper edge of a base flashing and its associated fasteners.
Diaphragm
A floor slab, metal wall panel, roof panel, or the like, having a sufficiently large in-plane shear stiffness and sufficient strength to transmit horizontal forces to resisting systems.
Double Lock Standing Seam
In a metal roof panel or metal cap, a standing seam that uses a double overlapping interlock between two metal panels. (see Standing Seam.)
Envelope
A continuous membrane edge seal formed at the perimeter and at penetrations by folding the base sheet or ply over the plies above and securing it to the top of the membrane. The envelope prevents bitumen seepage from the edge of the membrane.
Expansion Joint
A structural separation between two building elements that allows free movement between the elements without damage to the roofing or waterproofing system.
Factory Seam
A splice/seam made by the manufacturer during the assembly of sections of materials into larger sheets/panels.
Field Seam
A splice or seam made in the field (not factory) where overlapping sheets are joined together using an adhesive, splicing tape, or heat- or solvent-welding.
Flashing
Components used to weatherproof or seal roof system edges at perimeters, penetrations, walls, expansion joints, valley, drains and other places where the roof covering is interrupted or terminated. For example, membrane base flashing covers the edge of the field membrane, and cap flashings or counterflashings shield the upper edges of the base flashing.
Flat Lock
A method of interlocking metal panels in which one panel edge is folded back on top of itself and the other panel is folded under, after which the two panels are hooked together.
Lap Seam
Occurs where overlapping materials are seamed, sealed or otherwise bonded.
Miter Joint
a joint between two members at an angle to each other; each member is cut at an angle equal to half the angle of the junction; usually the members are at right angles to each other.
Pittsburgh Lock Seam
A method of interlocking metal, usually at a slope change.
Seam
A joint formed by mating two separate sections of material. Seams can be made or sealed in a variety of ways, including adhesive bonding, hot-air welding, solvent welding, using adhesive tape, sealant, etc.
Seam Sample
In single-ply and sometimes modified bitumen membrane roofing, a sample from the membrane that extends through the side lap of adjacent rolls of membrane, taken for the purpose of assessing the quality of the seam.
Single-Lock Standing Seam
A standing seam that uses one overlapping interlock between two seam panels, in contrast with the double interlocking used in a double standing seam.
T-Joint
The condition created by the overlapping intersection of three or four sheets in the membrane.
Tie-In
In roofing and waterproofing, the transitional seal used to terminate a roofing or waterproofing application at the top or bottom of flashings or by forming a watertight seal with the substrate, membrane, or adjacent roofing or waterproofing system.
Transverse Seam
The joint between the top of one metal roof panel and the bottom of the next panel, which runs perpendicular to the roof slope.
Valley
The internal angle formed by the intersection of two sloping roof planes.