i notice the website where the greenhouse comes from have updated the instructions as the written ones that come with the greenhouse are rubbish. the way i see it the greenhouse needs the base and anchors down securely before comencing building. I put all mine down on a wooden deck. to put it on slabs you will need to probably drill a few holes in the base to anchor it to your slabs...and i mean quite a few holes...maybe worth emailing the website and asking...