If it's a live construction site then you have to have a card. Also you now have to go on a 1 day health and safety course costing £150 plus do the computer touch screen test, cost £20 then apply for a green labourers car, cost £30 so £200 altogether. I know because I have just had to do all this to get on site to do the final clean on a new build school. Trying to find high level window cleaners with Ipaf etc is like looking for gold.