# Building a House

How a wooden house is framed from the concrete foundation up through the floor, walls, sheathing and roof trusses to the finished shell\.

By cosmic\-comet\-1c2f0840

Topic: Engineering

[Open the interactive Jig](https://ask.jig.com/j/ySjAjChwHpfm)

## Transcript

### 1. Building a House

Every wooden house starts as bare ground and a big pile of lumber\. Let's build this one layer by layer and discover what hides inside its walls\. Drag anywhere to turn the house around\.

This is a light wood\-frame house, a common way to build homes in North America\.

### 2. A strong foundation

First, concrete walls are poured on wide footings in the ground\. They lift the house off the damp soil and spread its weight\. A wooden sill plate, bolted on top, joins the wood to the concrete\.

The sill plate is pressure\-treated wood, because concrete can wick moisture up from the soil\.

### 3. A floor of joists

Joists are long boards standing on edge, set every 16 inches\. Big 4\-by\-8\-foot sheets are nailed on top to make the floor\. Because 16 goes into 48 exactly three times, every sheet edge lands on a joist\.

A board called a 2\-by\-10 is really about 1½ by 9¼ inches: drying and smoothing make it smaller\.

### 4. Walls are built lying down

Carpenters nail each wall together flat on the floor: upright studs between a bottom plate and a doubled top plate\. Over every door and window, a thick header carries the weight around the hole\. Then the crew tilts the wall up\.

### 5. A skin that keeps it square

Sheets of OSB, a board made of pressed wood chips, are nailed over the studs\. A bare frame can lean sideways like a wobbly bookshelf\. The skin locks every rectangle square, like the sides of a cardboard box\.

### 6. Triangles hold up the roof

Roof trusses are triangles of 2\-by\-4s, made in a factory and joined with metal plates\. A crane lifts them onto the walls, usually every 24 inches\. A triangle cannot change shape, so even thin boards make a stiff roof\.

### 7. Dried in

Sheathing covers the trusses, then a waterproof layer and rows of shingles\. Each row overlaps the one below, so rain runs off\. With a roof overhead, the house is dried in and indoor work can start\.

### 8. From frame to home

Windows, doors and siding finish the outside\. The glowing band shows the roof's weight travelling down through studs, floor and foundation into the ground\. The whole frame is still there, hidden under the paint\.