So when we bought our house the previous owner had a greenhouse put in on a concrete base, this concrete base has been the cause of my problems on a normal day the greenhouse can reached upwards of 35C and the hottest I've ever seen it was over 50C a couple of weeks back this obviously scorches everything inside i have tried different shade nettings etc but none really help, a neighbour advised I buy some of this paint on white shade for the glass and after looking around online and seeing it for 17 quid a bottle i went to my local garden centre today and bought 2 bottles for £14. Got home checked the temp inside at 33C and began to paint after it had dried and given sometime to work I walked in and it was down to 20c a vast improvement and maybe this year my tomatoes wont all be scorched to death.