Building doesn't rise

[thekillers 0]

 I just startedplaying SC4Deluxe like 3 mths ago, and not oftenly playing

I started Seashell (name of my city), and after 15 years, the residents and commercial building doesn't change to apartment or highrise office tower, why so?

I keep not to zone more for residential, because I think they will build vertically (the demands keep medium to high), but they're not, so my population is low (less then 5000 after 15 yrs? wtf)

thanks, I appreciate any suggestion.

[local_authority01 3]

You need to zone out before your sims start to zone up. As your population rises you unlock higher stage and taller buildings that will automatically be built depending on the density of your zones. At 5,000 population the largest stage your sims will build is a stage 6. Only 15% of your buildings can be this stage without adding more population and zones.

[Slashback 136]

You will need over 26,000 inhabitants to make the highrises appear.