If you’ve ordered a curb adapter design from Curbco (or anybody else, for the most part), then you’re already familiar with the submittal drawing, the drawing we create that shows precisely how the new curb adapter will fit in relation to the old or existing curb dimensions. This plan view diagram displays the outside diameter of the old or existing curb along the top and left sides, with a solid line outlining the adapter bottom and a slashed double line representing the new adapter top. Toward the right of the drawing you’ll see profiles showing how air will transition through the new RTU down through the curb adapter and the original curb. It will also show any degree over overhang that might extend beyond the original perimeter.
The submittal drawing shows exactly how the new adapter should work in conjunction with the curb and the RTU. Nothing is left to chance — except by the contractor who fails to check the submittal drawing against the real-life circumstances up on the actual roof. The problem is that no roof conforms to its perfect-perfect representation on the original blueprint. Anomalies develop. Holes get patched. Years of little modifications can manifest themselves as unanticipated projections or devices. The old part numbers may be unreadable or incorrectly listed. All these variables can cause unexpected problems at installation time — and that means lots of extra time, labor and expense.
Urge your contractor, in no uncertain terms, to take that submittal drawing up to the roof and compare the two with a fine-tooth comb, then report any variation, no matter how tiny. If you can factor those changes into account now, you can save everyone a lot of grief later. Making a new drawing is easy — making a new curb adapter isn’t!