What is the difference between a porch, a patio and a deck?
A deck is a raised timber or composite platform, a patio sits on the ground and is usually stone or pavers, and a porch is a roofed structure attached to the house, most often at the front door. The differences are not cosmetic: they change the permit, the cost and what the space is good for.
What exactly is a deck?
A framed platform on posts and footings, surfaced in timber or composite boards, usually attached to the house.
Because it is framed and raised, it can sit level with a first floor door and reach out over ground that slopes. That is its great advantage: a deck can be flat where a yard is not.
Being raised is also what brings guard rails, stairs and a bigger structure into the picture.
What is a patio?
A ground level surface, laid on a prepared base, usually in pavers, natural stone or concrete.
A patio has no frame and no footings, so it is a different trade and a different price. It also sits at ground level by definition, so on a sloping yard it needs the ground brought to it.
Level Line designs and manages paver patios with a licensed masonry partner, so the deck and the patio are planned together rather than fought over afterwards.
What makes something a porch?
A roof. A porch is a covered structure attached to the house, usually at an entrance.
That roof changes everything. It makes the space usable in rain, it changes the light inside the rooms behind it, and it makes the structure part of the house rather than an addition to the yard.
Level Line builds and rebuilds front porches and stairs, open, roofed or screened.
Which one do I actually want?
Match the structure to the level of your door and to whether you need shelter.
If your door is a step or two above the yard and you want to walk straight out, that is a deck. If the door is at grade and you want a dining or seating area, a patio is usually cheaper and needs no guard.
If you want to sit outside in the rain, or you want the front of the house to change, that is a porch. If you want shade on a patio without a roof, that is a pergola.
Can I have more than one?
Very often the right answer is a deck off the door and a patio beyond it.
That combination is common because it plays to the strengths of both. The deck handles the change in level at the house and the patio gives a larger ground level area for a table or a fire feature.
Planning them together is the important part. Two separate projects a few years apart rarely meet as well as one design that anticipated both.

More questions on this
Do patios need a permit?
Often not, because there is no structure, but it depends on the town and on drainage rules. Ask the building department.
Is a screened porch warmer than an open one?
Not meaningfully warmer, but it is far more usable in insect season, which for most people is the point.
Which is cheaper, a deck or a patio?
At ground level a patio is usually less. Once the ground has to be built up or a level change bridged, the picture changes.
