Measured Building Surveys for Architects — What You Need to Know

Why Architects Commission Measured Surveys

For most architects working on existing buildings — extensions, refurbishments, conversions, change of use — a measured building survey is the essential first step. Before you can design anything, you need to know precisely what's there. Working from the vendor's floor plans, old building regulations drawings or a client's rough sketch is a recipe for costly surprises on site.

A good measured survey gives you a clean, accurate set of as-existing drawings in DWG format that you can open immediately in AutoCAD or Revit and start working over. No redrawing, no guessing, no checking dimensions against a tape measure on site.

What to Specify When Commissioning a Survey

The more clearly you specify the scope at the outset, the more useful the survey will be. Key things to confirm before the surveyor visits site:

Drawing Types Required

Be explicit about which drawings you need. For most planning applications you'll need:

• Floor plans at all levels — typically 1:50 scale
• Elevations of all external faces — typically 1:100 scale
• Sections — at least one cross section, sometimes more depending on the complexity of the building
• Roof plan — usually required for planning where the roof is being altered

If you need internal elevations, reflected ceiling plans or any other additional drawing types, specify these upfront — they require specific measurement on site and can't always be added later from the existing data.

Drawing Scale

The industry standard for measured building surveys is 1:50 for floor plans and sections and 1:100 for elevations. If your planning authority or project requirements specify a different scale, state this clearly at the quote stage. Drawings produced at the wrong scale for a planning application will need to be reissued — which takes time you may not have.

Level of Detail

Standard measured building surveys show wall positions, door and window openings, ceiling heights, floor levels, sanitary ware, stairs, structural columns and key built-in features. Specify if you need additional detail — socket and switch positions, radiators, exposed structural elements, service runs — as these require additional time on site.

Coordinate System and Datum

For most projects, survey drawings are set to a local datum — typically ground floor finished floor level as zero, with heights referenced from there. If you need OS National Grid coordinates — for example, to tie in with a topographical survey or for a planning application requiring a geo-referenced location plan — specify this at the outset so the surveyor can establish the necessary control on site.

File Format and CAD Standards

Confirm the DWG version required (AutoCAD 2018 is the most compatible), your layer naming convention preferences, and whether you need the drawings in a specific template format. Providing your office drawing template or layer schedule to the surveyor before the job means the drawings arrive in your workflow with minimal setup time.

What You'll Receive

A well-structured survey delivery from SurveyX includes:

• DWG files — one file per drawing or set, layered with standard layer names, set up with the title block in paper space at the correct plot scale. Open and plot without any setup.
• PDF files — print-ready at the specified scale on A1 or A3 sheets, ready to attach to a planning application or share with the wider project team.
• Point cloud (where laser scanning is used) — RCP file for use in ReCap, AutoCAD or Revit as a three-dimensional reference dataset.

How to Use the Survey Data

In AutoCAD

DWG survey drawings from SurveyX are structured for direct use as an underlay or working file. If you're working in AutoCAD, you can either work directly in the survey file (add your proposed drawings on new layers) or xref the survey DWGs into your own drawing setup. Layer names follow industry conventions so they're immediately recognisable and can be frozen or isolated without any setup.

In Revit

If you're working in Revit, you have two options: link the DWG survey drawings into Revit as CAD underlays, or commission an as-built Revit model from us directly. The latter — built from the laser scan point cloud — gives you a three-dimensionally consistent Revit model that you can design over immediately, with accurate wall positions, floor-to-ceiling heights and structural geometry already modelled.

Loading the Point Cloud

If a laser scanning survey was carried out, the RCP point cloud file loads directly into Revit via the Insert → Point Cloud workflow. This gives you a three-dimensional reference of the entire building that you can slice at any level, view from any angle and snap to when placing model elements. Architects working on complex refurbishments find this invaluable for checking design decisions against the actual building geometry before issuing for construction.

Common Issues and How to Avoid Them

Survey doesn't cover the area needed for planning. Always confirm the extent of the survey at the outset — internal and external. If the planning authority requires the survey to show the neighbouring buildings or site context, state this when commissioning.

Drawing scale isn't right for the planning application. Check your local authority's validation checklist before commissioning — some require specific scales for specific drawing types. Get this right at the start rather than requesting amendments later.

Levels don't match between survey and topographical. If you're using a separate surveyor for the topographical survey, confirm both are using the same datum before either survey takes place. Mismatched datums between the building and site surveys create problems at planning stage.

Point cloud doesn't open in your version of Revit. RCP files are Autodesk format and load into any version of Revit from 2015 onwards. E57 files are the alternative for non-Autodesk applications.