A roof overhang is a simple shade for walls and windows. A good one can keep sun and rain off your house, and it is simpler to add at the design stage.

Results depend on your plan, your orientation and your budget, so ask your designer to size the overhang for your house.

01What an overhang does

It shades walls and windows from direct sun and keeps rain away from walls and openings. Both help keep the house more comfortable and last longer.

Shaded walls absorb less heat than walls in full sun.

Shade also protects windows and doors from rain, which helps them last longer. An overhang is a low-cost way to protect walls and windows from sun and rain. Example: a shaded window wall stays cooler than one in full sun at the same hour. Why this works: less heat reaches the wall, so less heat reaches the room.

02How deep should it be?

The right depth depends on the height of the window and the direction it faces. Ask your designer to check it against the sun path for your lot.

Too short does little, and too long can cut daylight or add cost.

Overhang depth is often a trade-off with budget and daylight, so ask your designer to explain it. There is no single correct depth, because every wall faces a different sun. Example: the overhang over a window facing south can be shorter than one over a window facing west. Why this works: matching the depth to the sun path gives you the shade you need without paying for extra roof.

03What to watch for

Overhangs catch wind in a typhoon, so the roof frame must be designed and fastened properly. Ask your engineer about this.

Check how rain flows off the edge and where the gutters go.

Ask how the roof edge is finished so water does not run back into the walls. A bigger roof edge catches more wind. Example: in a typhoon, a long overhang acts like a sail pulling on the roof frame. Why this works: asking the engineer to check the frame makes the shade safe as well as comfortable.

04Other ways to shade

Awnings, screens, louvers and trees can add shade where the roof alone is not enough. Ask your designer to compare them.

Every option has a cost and an upkeep need.

Remember to include overhangs in your floor area and roof cost estimates, since they add roof area. Overhangs are not the only way to shade. Example: a louver on one window and a tree near another may cost less than extending the roof all around. Why this works: comparing options lets you spend where the sun is strongest.

05Small details matter

A drip edge or a sloped soffit helps keep water from running back to the wall. Ask your designer how the edge is detailed. Small edge details decide whether an overhang protects the wall or soaks it. Example: a drip edge makes water fall away from the wall instead of running back along the soffit. Why this works: dry walls last longer, and you avoid stains and repairs.

06Questions to ask