Guide · Cost

What goes into the cost of a custom home in Forsyth County

There is no honest per-square-foot price for a custom home until you know the lot and the plan. What we can tell you is which line items set the number, which local fees people miss, and how to see the real costs behind any bid.

Why a square-foot price misleads

Two 6,000-square-foot homes can differ in cost by the price of a second house. The lot, the foundation, the finishes and the utilities move the number more than the size does. A builder who quotes a firm square-foot price before seeing your land is guessing, and you pay for the guess later in change orders.

The line items that set your number

1. Getting the site ready

Clearing, surveys, excavation, grading and the driveway come before any framing. On our Lakewood Lodge build, a 100-acre site took two surveys, clearing and excavation before the foundation was poured. A wooded, sloped or long-driveway lot can cost far more to prepare than a cleared subdivision lot.

2. Foundation

Slab, crawlspace or full basement, and how much the lot slopes. Walkout basements on sloped North Georgia lots add usable space but also concrete, waterproofing and drainage.

3. Structure and roof

Framing or a timber package, trusses, sheathing, roofing and windows. Complex rooflines and large window walls cost more than the square footage suggests.

4. Systems

Plumbing, electrical and HVAC, plus well and septic if there is no public water or sewer.

5. Finishes

Cabinets, stone, tile, flooring, trim, lighting and fixtures. This is where custom homes vary most, and where the allowances in a lump-sum bid are often set low.

Local costs people miss

Impact fees

Forsyth County requires impact fees on all new homes. Nearby, Milton's fee schedule lists $7,757.85 per single-family home. These are paid at permit time.

Permit and plan review fees

Some cities scale fees to construction cost. Alpharetta's 2026 procedures list $5.50 per $1,000 of construction cost plus $2.75 per $1,000 for plan review.

Septic or sewer

On septic, a county-issued septic permit, based on a soil evaluation, comes before the building permit. On sewer, you buy the tap or permit, such as Fulton County's in Alpharetta and Johns Creek.

Sealed plans and surveys

The City of Cumming requires plans sealed by a Georgia registered architect or structural engineer. Johns Creek requires a licensed survey.

Buffers and trees

Stream buffers and tree ordinances can push the house to a more expensive part of the lot or add replanting costs.

Lump sum vs. cost-plus

With a lump-sum bid, the builder sets one price and keeps the difference between that price and the real costs. You don't see the invoices, and changes are priced however the builder chooses.

RLG Atlanta builds custom homes cost-plus. Materials and subcontractors are billed at what they actually cost, plus our stated fee, and every draw comes with the invoices behind it. When you change a selection, you see what it really costs.

Ask any builder: Will I see the supplier and subcontractor invoices behind each draw? If the answer is no, you are trusting their markup.

How to get a real number

Pick the lot first, or narrow it to two. Site costs swing the budget most.
Have the builder walk the land and check septic, sewer, water and buffers.
Settle the plan and the allowances for finishes.
Get a line-item budget, not a single total, and ask how changes will be priced.

Before you buy land, read how to evaluate a building lot.

Sources

Rules and fees change. Confirm with the office before you rely on them. Last checked October 2026.

Talk to Jerry and Karen about your build.

Tell us about your land and your plans. We reply by phone or email.