For a home addition in New Jersey your architect almost always needs a topographic survey: a boundary survey of the lot with the existing house, driveway and improvements located, plus spot elevations and contours, delivered as a CAD file. It's what the site plan, grading plan and setback dimensions on the permit drawings are built from. A small one-story addition on a flat lot can sometimes get by with a boundary survey and a marked-up site plan — ask the architect and the zoning office.
Why a survey comes before the drawings
An architect designing an addition needs three things a survey provides and nothing else does: where the property lines actually are, so the addition can be dimensioned to the required setbacks; where the existing house sits relative to those lines, which is often not where the old survey or the tax map suggests; and the ground elevations around the house, so the new foundation, floor and drainage can be designed. Get the survey first and the drawings go faster and pass zoning the first time.
What's in a topographic survey for an addition
- Boundary — the lot lines established and corners recovered or reset.
- Improvements — house footprint, garage, driveway, walks, decks, sheds, fences, pool, with dimensions to the lines.
- Elevations — spot shots and contours across the yard, first-floor elevation, top of foundation, and grade at the house.
- Site features — trees over a certain size (many towns regulate removal), drainage structures, utilities where visible, easements from the record.
- Deliverable — a sealed plan plus a CAD file (DWG) your architect drops directly into the site plan.
How close can I build to the property line?
That's a zoning question, and every town's answer is different — side setbacks of 10 feet in one township and 5 in the next, rear setbacks of 25 or 30, with variances possible when you're close. What the survey does is establish exactly where the line is so the setback can be measured to the inch. Homeowners who plan an addition off an old fence line rather than a surveyed line are the ones who end up needing a variance, or worse, tearing out a foundation.
Shore additions and flood zones
In flood zones, an addition can trigger the "substantial improvement" rule and require the whole structure to meet current flood elevation standards. The survey's floor and grade elevations, combined with an elevation certificate, tell your architect early whether that's in play. On Lavallette, Ortley Beach and Toms River bayfront lots this is the single most important thing to know before design starts.
Cost and timing
A topographic survey is more field work than a boundary survey and includes the CAD deliverable, so it costs more — how much depends on lot size, terrain and how much needs to be located. Turnaround is typically one to two weeks. Send us the address and your architect's contact and we'll coordinate the scope directly with them.
Where we do this most
Addition surveys come to us from architects across the shore and the larger-lot inland towns: