Oops! My foundation is longer than my new house!

Scott Gibson, Contributing Editor

I have no idea how to handle a mistake that a building company made with my new modular house. The company provided plans for the foundation, and our concrete contractor followed those plans. But the foundation turns out to be 4 inches longer than our house. The company admits the error and offers two options: shave 4 in. off the foundation or patch it up with flashing and build a deck. What should I do?

Yikes. Goes to show why we like old houses on this web site!

The modular home industry has been taking pains to avoid this kind of publicity. Mistakes like this, no matter how unusual, must be a nightmare for the folks in the front office.

Right off the bat, neither of these ideas seems very appealing. You've paid for a house that should have fit its foundation. Let's look at the options one at a time.

Foundation walls are thick for a reason

Some builders argue that concrete foundations are over-built. There's way too much concrete, they say, for the weight it's asked to bear.

For some houses and in some soil types, this is probably true.

But if I wanted to save some concrete with a thinner wall, I'd consult an engineer, not a modular home company that just goofed up on the plans.

Besides, concrete is pretty hard stuff, even when it's green. It's not like working with nice, soft clay. I'm guessing the wall would be a mess when they got done with re-sizing it.

A deck covers the mistake but doesn't solve the problem

Idea No. 2 basically amounts to an old adage: What you don't know won't hurt you.

Except in this case you're resting the weight of the house on a wall that's 4 in. wide, not 8 in. wide. So the first question is whether that's enough concrete to adequately support your house.

Assuming for the moment that it is, you'd still have a potential water trap unless that 4 in. shelf was very carefully sealed with high quality flashing like copper or lead-coated copper.

In general, this plan has some problems even if you're getting a free deck.

Get out your camera and go see an engineer

I suppose they could send the trucks back and dismantle your new house.

After all, they didn't build it correctly.

But first, take lots of good photos of the problem. They might come in handy should you decide to report the company to state and local authorities.

Then go see a professional engineer and ask for some recommendations.

When you have the engineer's report, approach the modular home company and ask it to follow the engineer's recommendations. To the letter.

Get the company to pay for all remedial work, the engineer's time and any other expenses you incur. If the company wants to do the right thing, I'm sure you won't get an argument. And if they do argue, don't hesitate for a moment to hire a lawyer.

And then get a good break in the price for the house.

You will have earned it.

About the Author
An accomplished woodworker and carpenter, Scott Gibson is the former editor of Fine Woodworking magazine, and a former editor at Today's Homeowner and Fine Homebuilding magazines. He also is former managing editor of the Kennebec Journal, a daily newspaper in Maine.

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