The headlines in the new report on home building activity — which is being closely watched, after many other kinds of data point to a softening in housing — are pretty terrific.

The number of permits for new housing units soared 8 percent in April, the Census Bureau said on Friday, to an annualized 1.08 million. And the number of homes on which builders began construction rose a whopping 13 percent, to an annualized 1.07 million. If nothing else, the numbers help assuage fears that the housing industry is losing momentum. It now looks like the rough winter was indeed a major factor holding back home building activity so far this year, and there is now a spring thaw underway.

But even in the good new numbers, there is a clear trend evident: The entirety of the improvement is coming from more building of housing in structures with five or more units, most commonly rental apartment buildings.

The number of permits issued for single-family homes rose by a mere annualized 2,000 in April, whereas the number of units in so-called multifamily structures rose by 81,000. The same story applies for housing starts, where the number of single-family homes rose a measly 5,000, versus 124,000 for multifamily units.