50+ Specialist Calculators
Instant Results - No Sign-Up
Free to Use
Professional tools for serious builders
Home› Project Designer› House Extension Setup
House Extension Designer

Set Up Your House

Choose your house type and orientation - then open the 3D designer

Start by telling us about your house - its shape and how many storeys it has. Once you've made your selections, the 3D designer opens and lets you position your extension, choose how it attaches, and drag sliders to set the exact dimensions - width, depth, wall height and roof pitch - while you watch it take shape in real time.

When you're happy with the design, click Create Project Kit and we'll build you a personalised checklist of calculators pre-loaded with your dimensions - so you can work out materials for brickwork, foundations, roof tiles, insulation and more without re-entering a single measurement.

1House Shape
Rectangle
Square
Rectangle
Bar
L-shape
Small wing
Equal
Large wing
T-shape
Wide bar
Equal
Wide stem
U-shape
Narrow court
Equal
Wide court
2Number of Storeys
1
Bungalow
2
Two storey
3
Three storey
4
Four storey
3Attachment Type
Detached
Stands alone on plot
Semi-detached
One party wall
End of terrace
Party wall one side
Mid terrace
Party walls both sides
4House Dimensions
7Set Front Wall
⇧ Street / Front
Select a shape first

Rotate until the street-facing wall is at the top

8Front Door Position
Select a shape first
-
Wall
Party wall
Selected / door
9Garage