Planning and Layout
The key to any successful project is having a good plan. With a well thought out porch plan, you'll be able to visualize what the end result will be. You'll also utilize your time and materials more efficiently. Also, a good plan will assist in giving you an idea of how long it's going to take to complete the project.
Be thorough and take some extra time to develop a plan that fits your needs and tastes. A plan should answer some tough questions with sometimes tougher answers:
"Will the porch match and complement the house?"
"Is it in the best location?"
"How functional and convenient will it be?"
"Is it too big or too small for the yard and house?"
Sometimes it's hard to be objective about some issues. It may be helpful to ask a few friends to look over your plans and see if their ideas or views can enhance your design.
Keep in mind future updates and features for your porch plan. We designed our plan with the flexibility to have screen windows that would easily upgrade to sliding glass doors. That required large headers and temporary stud bracing which we put into the plan.
A final plan consideration is where to locate the entry from the house to the porch. It may be possible to utilize an existing window or door opening to save some time, framing lumber and allow the entry to fit in with the scheme of the house.
Permit & Inspections
Building a porch will likely require a local building permit. This usually involves submitting a sketch or drawing and construction details of your plan, getting that plan approved, and paying a fee for processing and inspections.
Scheduling inspections can be a job in itself. The number of inspections may vary in your area, but you will probably need had to have the footings, framing, wiring inspected before proceeding, and to pass a final inspection once the porch is completed. That's four visits (five if you're adding insulation), so schedule inspections accordingly.
WARNING: DOING WORK WITHOUT A PERMIT IS NOT ONLY ILLEGAL, BUT MAY ALSO INVALIDATE YOUR HOMEOWNER'S INSURANCE.
It's important to get the layout of the porch started straight and square with the house. Nail up a temporary guide board where the porch will set against the house. It's not really critical to set it at the precise height, because the entry will determine that. But set the board to run the width of the porch.
Set up batter boards at the far end corners (away from the house) a few feet past the length of the porch. Run a string line between the guide and batter boards to outline the sides of the porch. You can get the line going straight using a framing square, but check the line using the 3-4-5 method. You can also double the distances using 6-8-10.
Mark a point on the string 3 feet (36") from where the string hits the wall.
Mark a 2nd point on the house wall 4 feet (48") from where the string hits the wall.
Measure from the 1st point on the string to the 2nd point on the wall and move the string till the 2nd point is exactly 5 feet (60") from the 1st point. Then the string is square to the house.
Run each side string line out to the batter boards and hook each around a nail. Then run a front string line between the sides. Check it for square by measuring from the side string lines, again using the 3-4-5 method.
Check that the whole layout is square by checking the diagonal distances to make sure they're the same.
Our plan called for a center beam, perpendicular to the sides, to support the deck. It had footings underneath it, so we ran a string line to mark its location.
Once you've outlined the porch, flag the locations of the center of the footings.