As-Built Survey for Factory Buildings, Plant and Services

Why do factories need an as-built survey?

Because most plants have changed many times since the drawings were made, and the next change will be planned on whichever drawing is to hand. A shed was extended, a press line moved, an effluent drain rerouted round a new foundation, each by a different contractor. Few of them updated the master drawing. The survey draws the plant as it is, so the next expansion, approval or maintenance job starts from fact.

Four triggers are common: a planned expansion, an approval that asks for current drawings, or a sale, lease or loan valuation. The fourth is a near miss with an excavator.

The three layers of a factory as-built

A useful factory drawing covers the buildings, the plant inside and around them, and what is under the ground, each on its own layer.

• Buildings and site: Boundary, sheds, offices, cabins, roads, parking, gates, walls, ramps, yards and green areas, with floor and road levels.
• Structure and plant: Column grids and actual column positions, crane rail levels where needed, machine foundations, pits, trenches, pipe racks, tanks, chimneys, transformers and DG sets.
• Underground: Hydrant mains, water and process lines, effluent and storm drains, sewers, power and control cables, earth pits and abandoned lines still in the ground.

Not every job needs all three. A plant planning a new shed at one end may need the first layer in full, a check of the adjacent bays and the underground only where new foundations go. We scope it with you before quoting.

How we survey a working plant

Around production, not in spite of it: bays and timings are planned with your maintenance or EHS team under your permit rules. The crew attends the safety induction, wears the PPE you specify and stays out of restricted zones. Inside sheds, a total station traverse fixes columns, walls and foundations, because gps signals do not reach under a roof. Outside, DGPS from a base station ties everything to real coordinates, with total station detail between buildings and an auto level for spot levels on roads, floors and drains.

Busy aisles, forklift routes and crane bays are surveyed during shift changes, weekly offs or shutdowns. Where a line cannot stop, we measure from the nearest safe position and note it. Buried cables and metal pipes are traced with locators, and the rest is scanned with ground penetrating radar. Dense floor reinforcement limits radar depth, so chamber covers and trench lids are opened, with permission, to confirm the readings.

Approvals and records that lean on current drawings

Several routine processes ask for drawings that match the premises, and old drawings are the usual reason for delay. Plans of a new or extended factory are submitted under the state factory rules framed under the Factories Act, 1948. Consent to operate from the State Pollution Control Board ties effluent and emission details to the site layout. Fire safety certificates rely on hydrant, exit and storage layouts. Each authority has its own forms, signed by your architect or consultant; our part is accurate measured data to sign from.

Boundary questions sometimes surface here, on older estate plots above all. If the wall line is in doubt, see what you receive from land survey services for a demarcation against the allotment plan and its property boundaries.

What you receive

One coordinated drawing set with separate layers, so each department can use only what it needs.

We draw in your plant's layer names and title block if you send them. The same control marks then serve the construction layouts of the next expansion.

Rates, an example and timing

Factory as-builts are priced by site area, with the underground scan added only where you want it. Exclusive of GST:

• As-built survey: from ₹20,000 per site up to 5,000 sq m, then ₹3 per sq m beyond.
• Underground scan with GPR and locators: ₹24 per metre of scan line, minimum ₹50,000 in Delhi NCR and ₹1,00,000 elsewhere.
• Structural audit with NDT, if the as-built is part of a building health check: ₹5 per sq ft of built-up area, minimum ₹50,000.

Example: a 20,000 sq m plant costs ₹20,000 for the first 5,000 sq m and 15,000 × ₹3 = ₹45,000 for the rest, so ₹65,000 above ground. Field work takes three to five days, with drawings within a week or to an agreed programme for large plants. Our service page shows what an as built survey costs for other building types. Crews reach NCR plants, from Faridabad and Manesar to Bawal and Greater Noida, the same day or within 1 working day. Plants in other states get a locally based team member immediately or within 1 working day, and any mobilisation or travel cost, if applicable, is shown in the quote.

How do you keep the drawing current?

Make every contractor who changes the plant hand back measured mark-ups, and update the master drawing once or twice a year. The survey is a snapshot; within a year, new cable runs, a moved compressor or a fresh drain will change it. Write one rule into every work order: no final bill until the contractor returns a dimensioned sketch tied to the control marks we left. At a planned shutdown, a short visit folds those mark-ups into the master set and checks doubtful ones. Plants that follow this rule rarely need a full resurvey.

Before your next excavation

Use the drawing, but still register and scan the dig. Even a fresh as-built cannot show a cable laid last week by the electrical contractor. Our call before you dig in India guide explains the alert step outside the fence, and a short GPR scan of the exact excavation area inside it closes the gap. Send us the plant address, rough site area and any old drawings to talk to our project team.

Frequently asked questions

Can you survey without stopping production?

In most plants, yes. We work bay by bay around shifts and weekly offs, and only ask for short stoppages where a measurement cannot be taken safely otherwise.

Will you use our old drawings?

Yes, as a starting point and for layer names. The new drawing is measured independently, and the comparison note lists where the old one was wrong.

How accurate is the as-built?

Building and structural points by total station are typically within a centimetre or two; buried services carry the depth and position confidence stated in the report.

Can you measure crane rails and machine levels?

Yes, by total station survey and auto level. Precision alignment of machines is a specialist task we can support with data but do not replace.

Do you sign the drawings for approval submissions?

We certify our measurements. Statutory drawings for approvals are signed by your architect or consultant, using our data.

What does the underground report contain?

Each line with its type, depth and quality level, plus photos of opened chambers; see the Mezux guide: GPR survey deliverables for a full description.

Written by Saniya Parveen · Technically reviewed by Rahul Rai · Updated 8 November 2026