Add exterior walls right on your plan
Build → Exterior Wall. Tap a corner or any outside wall, pull the + for each new wall (or type its length), and end on an outside wall. Your plan grows to take in the new space, and the stretch of old wall now inside becomes an interior wall.
Most plans grow in shapes that aren't a plain rectangle: an L-shaped extension, a garage with a step in it, a porch across two walls. The Exterior Wall tool draws those walls straight onto your plan. You start on an outside wall, pull out each new wall (or type the length you measured), and finish back on the plan. The floor grows to take in the new space, and the old wall that ends up inside becomes an interior wall, keeping its doors and windows.
For a plain rectangular room, Add Room is quicker (see Add a room). For a bump-out of a wall you already have, split the wall and drag the middle piece out (see Split, slide and resize walls). Everything here also works with the plan rotated.
What you'll need
- •A design open in the editor, on a computer, tablet or phone
Step by step
- 1
Open Build and tap Exterior Wall
On a computer, Exterior Wall is the second tile under Structural in the Build panel on the left, between Add Room and Interior Wall. On a phone, tap Structural & Interior at the bottom of the screen; the tile is in the same place in the sheet. A blue note at the top of the plan says Click a corner, or anywhere on an outside wall, to start (Tap… on a phone), and every corner of your plan gets a blue dot.
Build → Structural → Exterior Wall. - 2
Tap where the first new wall leaves the plan
Move along an outside wall and a blue dot follows you, with the distance from each end of that wall, so you can start exactly 8 ft from a corner. Tap (or click) there, or on a corner. A short 2 ft wall appears, square to the plan, pointing outwards. At its end sit a crosshair and a blue + handle; its length shows in a small pill beside it, and a green right-angle mark shows the corner is square.
Hover an outside wall: the distance from each end tells you where you are. - 3
Set the first wall's length
The note now reads Drag + for the next wall, or the crosshair to change this one's length (or type it). Drag the crosshair to make the wall longer or shorter by eye, or type the number: on a computer just type the digits (an ft and in box opens; press Enter or tap the check mark), on a phone tap the length pill. Backspace takes the last corner back. Walls stay square to the plan while you drag, even with snapping off; hold Ctrl (⌘ on a Mac) for any angle, and the angle shows beside the length.
The first wall: crosshair, + handle, length pill, right-angle mark. - 4
Type the length you measured
Type 8 and press Enter: the wall becomes exactly 8 ft, and the crosshair and + move with it. You can type feet and inches (8 then 6 in the second box), or centimetres in metric. Do this for every wall you measured with a tape; drag only the ones you're sizing by eye.
Type the digits, press Enter: the wall is exactly that long. - 5
Pull the + for each next wall
Drag the + handle to draw the next wall from the end of the last one. While you pull, the new wall shows in blue with its live length, dashed guide lines line it up with the plan's walls, and the green mark appears when the corner is square. Let go to keep it, then pull the new + for the next wall. Each wall gets its own length pill, so you can type it right after drawing it. Undo takes back one wall at a time; Redo puts it back.
Pull the +: live length, guide lines, right-angle mark. - 6
End on an outside wall to close the extension
Pull the last + back onto the plan: onto a corner, or anywhere on an outside wall. A green ring marks the spot when you're on it. Let go and the plan grows: the new space gets a room label, its own measurements and flooring, and the stretch of the old outside wall that is now inside becomes an interior wall, with any doors and windows still on it. The view re-fits to show the whole plan. The new walls take after the wall you started from: same thickness, height, railing or load-bearing setting, and paint.
End on a corner or an outside wall: the green ring says you're there. - 7
Check the result
The extension is part of the plan: an 8 ft by 8 ft room here, labelled and measured, with the old right-hand wall now an interior wall between the living room and the new space. Furniture never moves; if a piece now sits in a wall, Smart Flow Check points it out. Tap any new wall to type its length, split it, or make it a railing, exactly like the walls you had (see Edit walls on the plan).
Done: the new room is labelled and measured, the old wall is interior. - 8
Undo one wall at a time, even after finishing
Drew the last wall wrong? Press Undo (Ctrl+Z, ⌘Z on a Mac) and only that wall comes off; the drawing tool comes back with your other new walls in place, so you can redraw it. Redo puts the wall back and finishes the extension again. Undo works the same way while you're still drawing.
Undo after finishing: just the last wall goes; the tool comes back. - 9
If the walls can't go there, the note says why
When you end a set of walls that doesn't work, nothing changes and an amber note explains: The new walls cross the plan or each other. Undo a corner and try another way. Other notes: These walls go inside the house. Exterior walls can only make the plan bigger — draw them outward., Start and end the new walls on an outside wall., Draw at least one wall out from the plan before coming back., A new wall would cut through a door or window. Start or end it beside it., and The new walls would build over a balcony or bay window. Undo a corner (Backspace or Undo) and carry on.
A set of walls that can't close gets an amber note; Undo a corner. - 10
Shortcut: pull the + at the end of any outside wall
You don't need the Build panel every time. Tap an outside wall to select it and a + appears just past each of its ends. Pull a + and you're drawing new outside walls from that corner, with the same length pills, guide lines and notes as above. (The crosshair at the end, inside the +, changes that wall's own length instead.)
A selected wall's +: pull it to draw new outside walls from that corner. - 11
On a phone
Tap Structural & Interior, then Exterior Wall; the sheet closes and the note at the top says Tap a corner, or anywhere on an outside wall, to start. Tap the wall and the 2 ft wall appears with the distance from each end of the wall shown along it. Drag the + for each wall; to type a length, tap its pill. Pinch to zoom in when you want a finer position.
Phone: the same tool, with the distances shown along the wall.
Tips
Type the measured walls, drag the rest
Right after each wall is drawn its length pill is ready: type the number from your tape measure and press Enter. The last wall closes on the plan by itself, so you only type the walls you measured.
Start on the wall, not on the floor
The first tap must be on an outside wall or a corner. The distance from each end shows while you hover, so start exactly where the extension begins on the real house.
Leaving the tool keeps your walls; Escape throws them away
If you close the note's × or pick another tool before ending on the plan, the walls you drew are kept and the plan closes back to them with an invisible open edge (dashed when you select it; tap its + to make it a wall). Pressing Escape instead discards the walls you were drawing; a second Escape leaves the tool.
Square by default, any angle on request
A plain drag always gives a wall square to the plan, whether the toolbar's snapping is on or off. For an angled wall hold Ctrl (⌘ on a Mac) while you pull, and the angle shows beside the length.
Common mistakes
Drawing the walls into the house
Exterior walls only make the plan bigger. Walls pulled into the floor are refused with These walls go inside the house. To divide the space inside, use Interior Wall or Add Room on an interior wall.
Ending the walls next to a window
A new wall can't cut through a door or window on the old wall. Start or end it beside the window, or move the window first.
Looking for Add Exterior Walls in the Outline Editor
That button is gone from the Outline Editor on indoor floors. Exterior walls are drawn on the plan with this tool, or by pulling the + at the end of a selected outside wall. (A yard still has Add Boundary in its own Yard Editor.)
Frequently asked questions
How do I add an extension, garage or porch to my floor plan?
Open Build and tap Exterior Wall. Tap the outside wall where the extension starts, pull the + for each new wall (or type its length), and end back on an outside wall. The plan grows to include the new space and the old wall between becomes an interior wall. For a plain rectangle, Add Room does it in one tap.
Why does the note say the walls go inside the house?
New exterior walls can only enclose more floor. If the walls you drew end up inside the plan, they're refused. Draw them outwards from the wall, or use Interior Wall for walls inside the house.
What happens to the old outside wall?
The stretch that is now inside becomes an interior wall, keeping its thickness, doors and windows. The rest stays exterior. Nothing else on the plan moves: furniture, fixtures and the other walls stay exactly where they were.
Can I type the exact length of each wall while drawing?
Yes. On a computer type the digits as soon as a wall is drawn; feet go in the first box, inches in the second, then press Enter. On a phone tap the length pill beside the wall. You can also select any wall afterwards and type its length (see Set an exact wall length).
Do the new walls match my existing walls?
They take after the wall you started from: its thickness, height, railing or load-bearing setting and paint. A plan with 10-inch outside walls gets 10-inch new walls. Change any of them afterwards in the wall's panel.
How do I undo one wall without losing the others?
Press Undo (or Backspace while drawing). Each press takes off one wall, including the last one after you've finished; the tool comes back with the rest in place. Redo puts a wall back.
Does this work on a phone?
Yes. The tool is under Structural & Interior; tap to start, drag the + for each wall, and tap a length pill to type a number. The notes at the top guide each step.
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