I think you should listen BGD, he has point, hell, I would send him PM to request his advices... what are benefits to buy the terrain and I build my own house?

Land loans are different from mortgages for home purchases. For lenders, land loans are riskier because the loan's collateral, the property, isn't being used for housing because of that risk, down payments and interest rates are higher for land loans than for mortgage loans. Oh yes, bgd is right.