A preliminary site plan is the first scaled map that places your custom home’s footprint onto your specific lot and shows the practical relationships that will drive design and permitting: property lines and setbacks, existing and proposed grades, driveway and utility locations, easements, septic or sewer connections, roof overhangs and building envelope, and any significant trees or rock outcrops. It’s more than a sketch — it’s a working document prepared from a boundary/topographic survey and often refined with input from a civil engineer or land planner so you can see how the house will sit, how water will flow, and what constraints will affect cost and layout decisions.
This plan is created early in the design process — typically during the schematic or site-design phase once we have a survey and a client brief — because it determines what is feasible on the lot before we finalize floor plans or lock in a budget. A preliminary site plan informs necessary next steps: whether a grading plan or soil report is required, if variances or HOA approvals are likely, what utility hookups are feasible, and whether the design needs to shift for solar access, views, privacy, or drainage. Producing the plan early helps avoid last-minute changes during permit drawings and gives a realistic basis for construction estimates.
For custom builds on Denver lots, preliminary site plans are critical because local zoning, lot topography and drainage, slope stability on hillside sites, and utility routing can all dramatically affect both schedule and cost. At RKM Homes we coordinate the survey, civil review and our design team to produce a preliminary site plan that spotlights permitting risks, budget drivers, and design opportunities unique to your parcel — enabling clear decisions about siting, foundation type, and site work before we move into detailed construction documents.
When should a preliminary site plan be created and what role does it play in the design and approval process for my custom home?
A preliminary site plan is one of the first deliverables after you’ve selected a lot and begun schematic design with your architect — typically created once you have a boundary survey and basic topography in hand. As an experienced builder I ask for that plan before we finalize the house footprint so we can confirm setbacks, easements, driveway and utility access, and any obvious grading constraints. The goal at this stage is not detailed construction drawings but a working diagram that shows where the house can sit, where site work will be needed, and whether the project can meet zoning and neighborhood rules before investing in full construction documents.
Practically, the plan serves as the coordination tool between you, your architect, civil engineer, and me. It lets us test multiple siting options against views, solar orientation, privacy, and entry/garage placement and produces the information municipalities or HOAs often need for preliminary feedback or entitlement discussions. We use it to identify potential red flags early — a required setback that eats a patio, an easement that blocks driveway routing, or a steep area that triggers retaining walls — so those issues can be resolved in design rather than discovered during permitting or construction.
As a homeowner, you can make the process smoother by getting the boundary/topo survey and any recent soils reports commissioned immediately after purchase and by scheduling an early meeting with your architect and builder to review the first draft. Expect the first preliminary plan within a few weeks and typically one or two rounds of revisions; use those revisions to lock in driveway location, primary orientation (views/solar), and major grading moves because changing those items later adds time and cost. The preliminary site plan is the decision point that turns a conceptual house into a buildable project, so treat it as the critical early checkpoint for approvals, budgeting, and scheduling.
What site information do I need for a preliminary site plan—surveys, topography, soils, utilities, and easements?
From our experience building custom homes in Denver and surrounding areas, the first documents you should get are a boundary/lot survey and a topographic survey from a licensed land surveyor. The boundary survey (often a plat or ALTA where required) shows property lines, monuments, and recorded easements; the topo adds contours, spot elevations, existing structures, driveways, retaining walls, significant trees and spot utilities. Ask the surveyor for both a georeferenced CAD (DWG) file and a print-ready PDF — architects and civil engineers use the CAD file directly for site planning. Expect costs roughly $800–$3,500 and a 1–3 week turnaround depending on lot size and terrain; fenced, steep, or heavily wooded lots are at the upper end.
A geotechnical (soils) report is the other critical piece we insist on before committing to foundation or slab layouts. A soils engineer will drill borings, test subgrade, and produce recommendations for bearing capacity, allowable settlement, frost-depth footings, slab-on-grade prep, and whether retaining walls need special design. Typical local costs run about $1,000–$3,000 and take 1–2 weeks after borings; more borings are needed on steep, filled, or previously disturbed sites. Make sure the geotech report includes recommendations we can use directly on the preliminary site plan (foundation type options, required excavation limits, and preferred backfill specifications) so the architect and structural engineer can size foundations appropriately.
Utilities and recorded restrictions complete the package you should hand to your designer before schematic site layouts. Have utilities located (811 and private locates), request capacity and tap-fee information from water, sewer, gas and electric providers, and locate existing wells or septic systems if present. Confirm all recorded easements, rights-of-way, covenants or HOA restrictions shown on the title work and survey — easements often limit where a house, driveway or buried services can go. Missing any of these items is a frequent cause of rework and cost increases, so we recommend coordinating the survey, topo, geotech and utility inquiries at the start of design so your preliminary site plan is based on complete, actionable information.
How does a preliminary site plan decide house placement, access, grading, drainage, and utility routing?
On the preliminary site plan we test several house placements to minimize earthwork while meeting your priorities — views, sun exposure for outdoor rooms or solar panels, preserving specimen trees, and the preferred garage/entry location. As a builder I ask owners to rank those priorities early because a 10–20‑foot shift on the plan can change foundation type (walkout vs. slab), add retaining walls, or change the amount of cut and fill. Ask to see proposed finished floor elevation numbers and contour lines so you can understand how much excavation or fill the layout requires and whether a walkout basement or stepped foundation is feasible for the lot’s slope.
Driveway alignment, grades, and emergency access are drawn on the preliminary site plan so we can avoid steep, unsafe approaches and costly rework. Practically, aim to keep long residential drive grades under about 8% when possible for year‑round use in Denver (try to avoid sustained slopes over 12% unless engineered for it), show turning radii for delivery and service vehicles, and identify snow‑storage zones where plowed snow won’t block sightlines or drainage. The plan will also indicate where retaining walls are likely, whether cut/fill can be balanced on site to reduce hauling costs, and the limits of the buildable pad so you don’t end up paying for last‑minute driveway lowering or massive wall foundations.
Septic and utilities must be routed on the preliminary plan so conflicts are found early — locate the septic reserve and drainfield with respect to roof runoff, downspouts, and irrigation to avoid saturation; keep primary sewer laterals and gas lines away from future patios and large trees; and specify proposed trench paths so you aren’t digging up new landscaping later. From my experience it pays to get utility service points (water meter, electric transform point, gas stub) confirmed during this stage and to request service trenches be shown on the plan, including access cleanouts and maintenance gates. Before you sign off, walk the plan with your builder/engineer to confirm septic setbacks, utility routing, driveway grades, and snow/maintenance access — resolving these on the preliminary site plan avoids expensive relocations during construction.
How will the preliminary site plan affect cost, schedule, bidding, and change management?
A solid preliminary site plan gives you a much clearer cost picture because it defines the big-ticket site items contractors price: earthwork volumes, retaining walls, foundation type, septic or sewer routing, long utility runs, and any required engineered drainage. As a builder I price two ways — a rough early estimate based on program and lot size, and a firm bid once the preliminary site plan is complete and tied to a boundary/topo and geotech report. Without that plan expect wide ranges and larger contingencies; with it you can get competitive, line-item bids that reflect true site impacts rather than a guess.
Timing the plan properly shortens the schedule. Producing the preliminary site plan early in design lets civil engineers and utility partners review conflicts and start permit checks while architects finish details. That means site work contractors can be scheduled and long-lead materials (retaining systems, deep foundations, septic tanks) ordered sooner. If the site plan is incomplete or changed after mobilization you’ll see hold-ups: crews idle, rework of grading or utilities, and permit re-submittals — all adding weeks and cost.
Changes after bidding are the most common source of cost creep; handle them with clear change-management rules in your contract. I recommend owners require geotechnical and boundary verification before final bids, ask bidders to submit unit pricing for typical site adjustments, and include an explicit contingency (commonly 5–15% depending on complexity) for unforeseen conditions. Also set firm decision milestones in the schedule so any owner-driven plan changes trigger a written change order with time and cost impacts; that keeps expectations aligned and prevents small design tweaks from ballooning into major budget and schedule surprises.