Where the House Sits
The same plan, four different houses
Hand one floor plan to four builders in Vermont, Arizona, Louisiana, and the Florida coast, and you will get four different houses. The rooms are the same. The roof, the walls, the foundation, and even the color change, because each place has its own weather to answer. Deciding where a house sits is the first design decision, and it is made before the first wall is drawn.
Climate regions
Designers sort the country into a few broad climate regions. Each one has a problem the house must solve:
| Region | The problem | What the house does about it |
| Cold and snowy (northern states, mountains) | Heavy snow, deep frost, long heating season | Steep roof, thick insulation, small windows on the north side, deep footings or a basement |
| Hot and dry (desert Southwest) | Fierce sun, little rain, cool nights | Thick light-colored walls, low roof, small windows, shaded courtyards |
| Hot and humid (Gulf and Southeast) | Heat plus moisture, heavy rain, mold | Wide overhangs, porches, raised floors, lots of cross-ventilation |
| Mild and wet (Pacific Northwest) | Months of drizzle | Big overhangs, good drainage, siding that sheds water |
| Windy coasts (hurricane country) | Storm winds and flooding | Hip roofs, strapped-down framing, living floor raised above flood level |
No region is easy. Every one of them is simply a different list of problems.
The roof answers the sky
The roof is the part of the house that meets the weather first, so climate shapes it most.
Pitch is the steepness of a roof, written as inches of rise for every 12 inches of run. A 4:12 roof climbs 4 inches per foot and looks nearly flat from the street. A 12:12 roof climbs a foot per foot, a 45-degree slope. Snow country uses steep roofs because snow is heavy, roughly 15 to 20 pounds for every square foot of a one-foot-deep wet snowfall, and a steep roof lets it slide off instead of stacking up. The desert has no snow to shed, so a low roof is cheaper and keeps the house lower and cooler. Rainy places fall in between: enough slope to move water fast, not so much that the roof costs a fortune.
Overhang is how far the roof reaches past the wall. In a wet climate the overhang keeps rain off the siding and away from the foundation. In a hot climate it does something smarter.
In summer the sun stands high in the sky, and a two-foot overhang shades the window below it all afternoon. In winter the sun rides low, slides in under the same overhang, and warms the room for free. In the northern half of the world that free heat comes from the south side of the house, so cold-climate designers put the big windows on the south wall and keep the north wall nearly blank. Blueprint Lab sets both pitch and overhang in Building Specs, and the elevations and 3D view redraw as you change them.
The ground answers the cold
Soil holds water, and water expands when it freezes. The depth to which the ground freezes in a normal winter is the frost line. Near the Gulf of Mexico it is a few inches. In Minnesota it is four or five feet.
A footing that sits inside the frozen band gets lifted every winter and dropped every spring, a motion called frost heave, and over a few years the walls above it crack. So the rule is simple: footings go below the frost line. In warm states that means a thin slab poured right on the ground is fine. In cold states the footing has to be dug four feet down anyway, and once you have dug that far you may as well dig a little more and get a basement. That is why basements are everywhere in the North and rare in Texas and Florida. Blueprint Lab's foundation choices, slab, crawlspace, and full basement, are really a climate choice.
The walls answer the heat
Insulation is anything that slows heat moving through a wall or roof: fluffy fiberglass, foam boards, dense cellulose. It is rated by R-value; a higher number slows heat more. A cold-climate wall may carry twice the R-value of a wall in San Diego, which means thicker walls and deeper window sills. Hot climates care about the roof most, since the attic is where the sun beats hardest, and about color, since a white wall reflects heat that a dark wall soaks up.
Materials follow the same logic. Stucco and brick stand up to years of sun. Wood siding wants a dry climate or a very good paint job. Cement-board siding shrugs off humidity and termites. Metal roofs shed snow and survive embers in wildfire country. The material list on the elevations is a climate decision wearing a style decision's clothes.
The site itself
Zoom in from the region to the lot, and more decisions appear. Which way does the land slope, and where will rainwater run? Water must drain away from the house on every side. Where are the big trees, and do they shade the south windows you were counting on? Which direction does the street face, and can the living room still face south? Where do the winter winds come from, and can the garage block them? A good site plan answers all of this with the house drawn on its lot, with north marked, before the floor plan is final.
🔤 Words to know
🛠 Mini activity: Same house, two climates
- 1Wall toolTrace the dashed 30 by 24 outline with the Wall tool (type 30' or 24' and press Enter for each wall). No rooms needed; this activity is about the shell.
- 2Snow country first. Open the Section Views tab. In the Building Specs panel find Roof → Pitch and set it to 8 or steeper so snow slides off.
- 3The frost line here is four feet down, so the footings must be deep anyway. In Building Specs → Foundation → Type choose Full basement.
- 4Open the 3D View and look at the steep roof and the deep foundation together.
- 5Now move the house to the desert. Back in Building Specs → Roof, set Pitch to 4 or lower and Overhang to 24 or more to shade the walls.
- 6Finish the desert version: Exterior → Default material → Stucco or Brick, and Foundation → Type → Slab on grade, since the ground here never freezes.
✅ Check: Where the House Sits
- Mini activity: every step needs its ✓.