Don't know and can't think of a better term, but that's basically what it is, in principle, a/c to Dicobat:

RELEVÉ n.m.
1/ ARCHIT.: lever* d'un plan. Plan détaillé levé* sur un édifice ou un ouvrage existant.

Dicobat proposes "as-built drawing" for this, but I see this rather as the drawing of a recently built building, whereas I take the "relevé" to be that of an OLDER existing building, one for which interior revamping is required for instance.

No need to call it "architecture".

"No calculations or record drawings of the existing structure, including the new steel frame were available on site. We therefore have been unable to review ..."
194.201.98.213/WAM/.../Correspondence-429587.pdf?

"All applications for such development must be accompanied by detailed drawings of both the existing structure and the proposed development. ..."
www.tynedale.gov.uk/business/planquery.asp?id=450

"plans clearly showing the location of the structure to be demolished; photographs and/or elevational drawings of the existing structure. Internal works ..."
www.brent.gov.uk/tps.nsf/Pages/LBB-15






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Note added at 2 hrs (2009-06-29 14:31:30 GMT)
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Or, even briefer, "existing drawings", but that is more of a verbal shorthand term and can be confusing unless the context makes it clear what is meant, e.g.
"Existing and proposed drawings should be submitted. Again, they may be drawn separately or the new work may be indicated by shading etc. ..."
www.east-northamptonshire.gov.uk/ppimageupload/image12746.p... -

or plans layout. That is to say, how everything - the buildings and everything else that composes these structures is planed, structured or laid out.