How a Renovation Set Shows Existing, New and Demolition

Why this matters

A new building is drawn once. A renovation is drawn twice for every trade: once to say what comes out, once to say what goes in, with everything that stays shown on both. A service shop bidding a remodel from only the new-work sheet misses the demolition labor; one working from only the demolition sheet removes things the new-work sheet needed kept. The costliest mistakes on remodels are rarely in the new work. They are in the line between "remove" and "remain", and that line is drawn in a grammar of screening, dashes and keyed notes that has to be read across two sheets at once.

Before anything drawn as "remove" comes out

Demolition drawings say what is to be removed. They do not say it is dead, empty or safe to cut.

• Electrical. Every circuit feeding an item to be removed is identified and de-energized at its source, then proved dead by a qualified person with a tester checked on a known live source before and after (NFPA 70E Article 120, 120.5 in the 2021 edition, renumbered in 2024; work practices under 29 CFR 1910.333(b)(2), or 1926.417 on construction work). In an occupied building, assume a circuit in the demolition area also serves somewhere outside it until you have traced it.
• Gas. A gas line shown for removal is shut off, capped and tested by a licensed gas fitter before anyone cuts near it. If you smell gas during demolition, everyone leaves the area at once without operating switches or tools, and the call goes to the gas utility from outside.
• Water and drains. Supply lines are isolated and drained, and the valve that isolates them is tagged so nobody reopens it onto an open pipe.
• The materials themselves. A demolition plan does not say what a wall, ceiling or floor is made of. Older finishes can contain lead paint or asbestos. Federal rules (the EPA asbestos NESHAP for regulated facilities, which excludes most houses of four or fewer units, and the EPA lead renovation rule, 40 CFR 745, for pre-1978 housing and child-occupied facilities) and state rules decide when a survey and certified workers are required. If the set or the GC cannot tell you a survey was done, ask before you disturb anything.

The three states, and how each is drawn

Every item on a renovation drawing is in one of three states. The convention most firms use, at least as a starting point:

Two more states show up often enough to know: existing to be relocated, commonly drawn as removed on the demolition plan and as new (or with a tag such as "ER" or "RL") at its new spot; and remove and reinstall, where the same item comes out and goes back in the same place, usually after work behind it. Both appear on both sheets. A firm may also put all three states on one sheet with tags like E, R and N instead of separate plans. The legend on the set governs; this table is a first guess.

Demolition sheets often carry their own number series, such as AD-101, MD-101 or ED-101, or a "D" in the sheet title. See Sheet Numbering and Discipline Letters on a Drawing Set.

Keyed demolition notes

Demolition plans rarely write instructions on the drawing. They put a numbered tag, commonly in a hexagon or a circle, next to the item, and the numbered list of keyed notes on the side of the sheet says what to do. "Remove receptacle and wiring back to nearest device to remain" is a very different job from "remove receptacle, abandon wiring in place." The tag on the drawing is meaningless until you have read the note it points to, and a note number used ten times on one sheet is ten instances of the same instruction.

The words in those notes carry scope. Phrases worth knowing, because each one prices differently:

• "Remove back to main and cap." Take out the branch duct, pipe or cable all the way to where it leaves the main or the source, and seal the opening there. More labor than it looks, and it can reach outside the room.
• "Cut and cap" or "cap at wall" or "cap below floor." Remove only to the stated point and seal it, leaving the rest in place.
• "Abandon in place." Disconnect it from service and leave it where it is. Whether abandoned wiring or piping is allowed to stay is a code question as adopted locally, so the note is the designer's call, not yours to extend.
• "Protect in place." It stays and must be shielded from the work, and who pays to repair it if it is damaged is set by your contract's protection clause, so read that before you start.

One room, two sheets

Room 104 is an office getting a closet folded into it. The electrical demolition plan and the matching new-work plan:

DEMOLITION PLAN, ROOM 104 (ED-101)
 dotted = existing to remain   - and : = remove

 . . . . . . . . . . . . . . : . . . . . . .
 .  rcpt                     :             .
 .                     rcpt- :  CLOSET     .
 .  fix      fix             :             .
 .                     rcpt- : <1>  <2>    .
 .  fix- -   fix- -          :             .
 .  <4>      <4>             :             .
 .        jbox . . . . . . . : . . . . . . . -> RM 105
 .         <3>               :             .
 . . . . . . . . . . . . . . : . . . . . . .

NEW WORK PLAN, ROOM 104 (E-101)
 dotted = existing   capitals = new

 . . . . . . . . . . . . . . . . . . . . . .
 .  rcpt                                   .
 .                                    RCPT .
 .  fix      fix                           .
 .                                    RCPT .
 .  A        A                             .
 .                                    RCPT .
 .        jbox . . . . . . . . . . . . . . . -> RM 105
 . . . . . . . . . . . . . . . . . . . . . .

Keyed notes on ED-101:

1. Remove receptacle and wiring back to the nearest device to remain.
2. Partition removed under architectural demolition, see AD-101. Remove all devices and wiring in it.
3. Existing junction box and circuit to remain. Circuit continues to Room 105; maintain service.
4. Remove light fixture; cap wiring at the junction box above.

A worked read: pricing Room 104 from both sheets

From the demolition plan alone: remove two receptacles on the partition (note 1), remove two light fixtures (note 4), remove all wiring in the partition (note 2). Remaining in place: one receptacle on the north wall, two light fixtures, and the junction box (note 3). That is four devices out.

From the new-work plan alone: three new receptacles on the closet's far wall, now the room's east wall, and two new type A fixtures where the removed fixtures were. The north-wall receptacle, two fixtures and junction box show dotted as existing, so they carry no new material. Five new devices.

From the two read together: look at the junction box line. On the demolition plan the circuit to Room 105 leaves the junction box and passes through the partition that note 2 says to strip of all wiring. On the new-work plan the same circuit still runs to Room 105. The two notes, read separately, conflict: note 2 clears the partition and note 3 keeps a circuit that runs through it.

The resolution is a task that appears on neither sheet as a drawn item: before the partition comes down, reroute the Room 105 circuit above the ceiling, clear of the wall, and confirm 105's devices still work afterward. It is real labor, and the only way to find it was to lay ED-101 next to E-101. Priced from either sheet alone, the bid misses it; built from the demolition sheet alone, the crew strips the partition per note 2 and the tenant in 105 loses power on a Tuesday morning.

The price for this room is therefore three parts: four devices out plus the partition wiring, five devices in, and one circuit rerouted, with the reroute written into the bid as its own line so nobody wonders later why it took longer.

What would change it. If note 3 had said "existing circuit to Room 105 abandoned, Room 105 refed under separate scope", the reroute would vanish and the crew could strip the partition clean. That is exactly why the note numbers, not the line types, decide the work.

The "existing to remain" item that crews remove by mistake

It is rarely a device you can see. Fixtures, receptacles and diffusers drawn to remain are obvious, and crews leave them alone. The item that gets cut is the one drawn as a screened line passing through the demolition area on its way somewhere else: a circuit, a water line, a duct, a condensate drain, a low-voltage cable, serving a space that is not part of the job. On the demolition plan it is gray and easy to read past. In the wall it is a cable or pipe tangled with everything that is coming out. The tell on the drawing is a screened line that crosses the demolition boundary and does not end inside it. Trace every one of those before demolition starts, mark it in the field, and check with the GC who it serves.

Verifying the read before the first cut

• Every dashed item on the demolition plan has a keyed note read and a matching absence on the new-work plan, or a relocation shown there.
• Every screened line that crosses the demolition boundary is traced to what it serves and marked in the field.
• Every item on the new-work plan drawn as existing is confirmed in the field to actually exist in the condition the set assumes. See How to Field-Verify Existing Conditions Before You Order.
• The safety items above are done and recorded for every system in the demolition area.

Acceptance is all four, with any conflict between a demolition note and the new-work plan written up as an RFI before demolition, not discovered during it.

References

• NFPA 70E, Standard for Electrical Safety in the Workplace, Article 120 (current edition), and 29 CFR 1910.333(b)(2) and 1926.417 for de-energizing and verifying circuits
• EPA asbestos NESHAP (40 CFR Part 61 Subpart M) and EPA Renovation, Repair and Painting Rule (40 CFR Part 745), plus your state's equivalents
• See related: As-Builts and What Happens When Nobody Updates Them; How to Field-Verify Existing Conditions Before You Order
• See related: Line Types and Line Weights on a Construction Drawing; How to Check Your Scope Against By-Others and NIC Notes