庭 and 屋根: gardens and roofs
Distinguish outdoor space around a home from the covering above a building.
Activities in a garden
庭 (にわ) means garden or yard. 「庭で花を育てています」 describes growing flowers in the garden.
「庭に出ました」 means going out into the garden. に marks the destination.
The roof as a building part
屋根 (やね) means roof. 「屋根の上に鳥がいます」 locates a bird on the roof.
「赤い屋根の家です」 describes a house with a red roof. 赤い does not necessarily describe the entire house.
Viewpoint versus object viewed
「庭から屋根を見上げました」 means looking up at the roof from the garden. 庭 gives the viewpoint and 屋根 the object viewed.
「庭の木が屋根より高くなりました」 says the garden tree grew taller than the roof. より marks the height comparison's reference.
Does 「赤い屋根の家」 mean every part of the house is red?
Show the answer and why
No. The roof is the part explicitly described as red.