How to Modify a Stock Plan with
a Post and Pier Foundation

Note: For an overview of the general topic of modifying stock plans, click HERE.

Let's say you have found a plan that has the general width you want in your house or cabin. In this case we will use an example of a 20' wide by 32' foot long cottage home. The plan is similar (but not exactly the same) as some of the cottage home plans on Let's say the foundation plan you get with the stock plan set has something like the diagram below. The floor joists span the width of the building and sit on beams which in turn rest on piers at some specific spacing.

The plan you will modify should have about the same loads coming down onto the beam and piers. Therefore figure out first if you will be building a single story buiding or whether or not it has a loft or a second floor. These loads will determine the size of beams and the placing of the piers and thus you want a foundation plan that matches your loads.

Now, lets assume you want to change the length, by making it say 24' or 38' long. You can do this by simply modifying the existing foundation plan. You can use the same beam and joist system and either lop off or add piers as the length requires. Just make a couple of copies of the foundation plan and cut out or paste in an extra section in the middle of the foundation plan. Change the length measurement with white out and pen. Voila, a new foudation plan.

For changes that don't fit the spacing module of the piers, just readjust the spans making sure that the new spans don't exceed the spans on the plan. Then the beams will just be a bit stronger (which is not a problem). You can do this with a dimension note. Change the measurements and add "NTS" (not to scale). This tells the inspector and foundation contractor to use the written dimension and not to scale off the plan.

post and pier foundation

Click Little House Plans Kit for small (up to 14' wide) post and pier house plans.

Click the blue links for a 20' wide one-story, 1-1/2 story, and 2-story cottage plan.

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