It takes two to three years for the initial settlement of a newly constructed home, and the majority of it happens in the first year. That time-frame can be longer, or a little shorter, based on factors like soil composition, how much the ground was disturbed, and then how well it was recompacted to create the building pad. 

Minor Floor Cracks Are Not Settlement

    Homeowners are on lookout that first couple of years for any telltale cracks that indicate there might be a built-in structural problem. And the one place they are often found is the garage floor. Garage floors get noticed for two reasons: 1) The garage is usually the only floor in the home that does not have a covering, and 2) concrete shrinks slightly, opening up a few hairline cracks as it cures, and they are to be expected. There are also probably other hairline cracks under the areas of carpet or tile in the rest of the house, but they are out of sight.

    This does not mean that a new house can’t develop disturbing cracks and structural problems early on. Just that a few hairline ones are normal and to be expected. Two articles about ways some builders use to minimumize floor cracks are What is fiber reinforced concrete? and Why is there a "WARNING! POST-TENSION SLAB" sticker in my house?

After The House Settles

    A long list of environmental factors begin acting on a house structure from its very first days. This is typically a slow, incremental process that adds up over time. Here’s just a few examples:
•• Tree roots that grow under the foundation can gradually lift under a wall.
•• Soil movement due to site drainage problems may erode around or under the foundation.
•• A sinkhole can develop underground.
•• Sun and rain deteriorate surfaces, which allows water intrusion, followed by structural damage, if the surface coatings are not maintained.
•• A vein of clay soil under the home can be activated by an extremely rainy season, and begin to swell the soil under the foundation.
•• Seasonal cracks that come and go due to changes in temperature and humidity can happen.
•• The foundation itself can deteriorate due to corrosion, spalling, or rising damp.

    So if you notice a crack more than about 1/8” wide in the walls or ceiling, or one that’s growing, or emanating from the corners of windows, or doors that are difficult to operate, or fractured window panes—then it's time to look a little closer around the house for other symptoms. We suggest reading a couple of these articles first:

• How do I recognize serious structural problems in a house?

• Where are the places to look to find structural cracks in a house?

• What are the common problems of different types of house foundations? 

• Why is my stucco cracking?

• What causes vertical cracks in fiber cement siding planks?

• What causes raised white lines of residue on a block wall that are crusty and crumbling? 

• What causes stair-step cracks in a block or brick wall? 

• Why is the concrete window sill cracking?

• What causes a horizontal crack in a block or brick wall? 

• How can I tell if a diagonal crack in drywall at the corner of a window or door indicates a structural problem?

• What would cause long horizontal lines of brick mortar to fall out? 

• How do I recognize structural problems in a retaining wall?     

• Why did so many concrete block homes collapse in Mexico Beach during Hurricane Michael?  

• What causes a vertical crack in an exterior concrete block or brick wall?

• What causes a vertical crack in drywall? 

• What causes drywall cracks in the ceilings and walls of a house? 

• How can I tell if a crack in a stucco wall is a structural problem and what is causing it? 

• What causes cracks to open along the line between the ceiling and walls? 

• How can I tell whether my house foundation problems are caused by a sinkhole or expansive clay soil?

• How can I avoid buying a house with clay soil heaving foundation problems?