Welded deck seam skin pontoon internal floating roof

A system, comprising:

• a girder comprising a first top channel extending in a first direction inward from a top surface of the girder and extending in a second direction along a first length of the girder;
• a first deck sheet disposed on the top surface of the girder and on a first side of the first top channel;
• a second deck sheet disposed on the top surface of the girder and on a second side of the first top channel;
• and
• a cap channel comprising:
• a first leg and a second leg, wherein the first and second legs define a bottom channel;
• a first foot configured to capture the first deck sheet against the top surface of the girder, wherein the first foot is welded to the first deck sheet;
• a second foot configured to capture the second deck sheet against the top surface of the girder, wherein the second foot is welded to the second deck sheet;
• and
• a first arm and a second arm, wherein the first and second arms define a first roller recess, a second roller recess, and a second top channel;
• wherein the first and second legs are configured to be inserted into the first top channel of the girder and to receive a fastener.

A method of assembling a floating internal roof, comprising:

• assembling a rim;
• installing a first plurality of girders extending across the rim in a first direction;
• installing a second plurality of girders, wherein the second plurality of girders extend in a second direction, cross-wise to the first direction, and wherein the second plurality of girders extend between the first plurality of girders;
• positioning a plurality of deck sheets on top of the first plurality of girders and the second plurality of girders;
• installing a plurality of cap channels, comprising coupling a first cap channel of the plurality of cap channels to a respective girder or the first plurality of girders or the second plurality of girders, wherein a first foot of the first cap channel is configured to capture a first deck sheet of the plurality of deck sheets against a top surface of the respective girder;
• and
• welding the first foot to the first deck sheet.