Best way to make improvised building in arma??

Hey guys,so i set my self a task to make in arma 3 CQB areas,Buildings rooms apartment buildings(maybe :D)

But now i am stuck on 1st floor because i cant get a proper material for the floor,i used pallets but you can see trough them,and if i just place more it will not be possible to see trough them but i want to minimize object amount, now for walls i used a Shoot house walls then i got to idea maybe i can use them like floor if i manage to rotate them,so i used in init this setvectordirandup x,y,z and i made it,panel was turned around and acted like a floor,but when you try to walk on it,there is the problem,seems that arma engine is not accepting walking on walls :391: so yea,i have great building and i hate to leave it on 1 floor if i can go up, even made a stairs

This is what i made so far :)

http://i.imgur.com/GWiptfr.png

Any sugestions how i could make a proper floor for the building? and keep in mind that i will use only arma 3 vanila stuff :)

Tnx