Once a buyer receives a mortgage commitment, the modular house can be ready for occupancy in six weeks, he noted.

"The process may take another month after the mortgage commitment," Ms. Kennedy said.

For example, he said, lenders frequently issue mortgage commitments subject to an appraisal of the property.

A bank may require a new well before it makes a mortgage commitment.

It is a sad fact that many people over-extended their mortgage commitments and now face difficulties.

Then, a day before my mortgage commitment was to end, they called again.

The next vulnerable moment is when the buyers get - or are turned down for - a mortgage commitment.

Some banks help family members who would live together to pool resources and co-sign the mortgage commitment.

Once there are contracts and mortgage commitments, the houses go up in clusters.

Mr. Zucker said he had his foundation permit, approved plans and a mortgage commitment for the 12-story building.