Getting porch details right can be tricky, but by anticipating where common mistakes typically occur, you can achieve a design that seamlessly expands the living area of a home. A key porch detail, and one that is commonly botched, is the alignment of the top of the post and the beam it supports. Misalignments occur when the rough and finish dimensions are not coordinated.

On a typical project, the framer will align the rough beam with the foundation. But if a finish material will be added to the beam or to the post, this can result in a beam that is proud of the post, or vice versa. This issue may be further exacerbated when using a tapered column. For this reason, I almost exclusively use square posts to ease installation and to minimize the chance of misalignments.

To get this detail right, first determine the size of the finished post and set the width of the finished beam to match. Then work backward to determine the rough dimension of the beam. Make sure your framer has a drawing other than the foundation plan that calls out the rough-beam location.

To get a porch to look right, you’ll have to consider the height and dimensions of the posts, and the spacing between the posts. For the height, start with a 9-ft. post and adjust as needed to fit the overall composition of the home’s elevation. Avoid posts shorter than 8 ft., which will feel too low, or taller than 10 ft., which will make the porch feel uncontained.

For cottages and smaller homes, 6×6 posts with a simple chamfer are a good place to start. As the home gets larger, you can either double up the posts to visually give more support or use larger posts like 8x8s. Keep in…