Hana ʻia ke kila kila me ke kila palahalaha a me ke kila wili e like me kekahi spacing a me nā kaola kea (wili ʻaoʻao huinaha, kila huinaha, kila poepoe, kila pālahalaha, a me nā mea ʻē aʻe), a hoʻopili ʻia i loko o kahi huahana anti-skid kila me kahi pahu pahu i loko. ka waena, Steel gratings ua nui hoʻohana 'ia no ka auwai uhi, kila hoʻolālā paepae papa, paepae alapiʻi a pela aku.