Disclosure: I work for KEVA planks....   I suggest you check out KEVA planks from Mindware.  (Same dimensions as Kapla)  KEVA planks come in maple which is made in the USA and pine (like Kapla and Citiblocs) which is imported.  Kapla and KEVA structures tend to hold together better because the blocks are cut with such high precision.  If the structures fall apart easily, it is probably because of cheap quality.   There's a reason their blocks are cheap.   Pine...