Can anyone advise my house was built in 2000 and I'm in the process of having a rear extension built today the builders have started to construct a pad stone for a Steel Column to sit on. Down so they have broken through the old block and beam floor and to my Surprise and my builder the Floor Construction on my existing house is only and 350mm map then block and Beam a dpm then 40mm of screed!!!! no insulation at all I have always wondered why my feet are so cold in the winter standing on the tile floor. now the plan was (now this was a plan now re-evaluating lol)to remove all the old screed and insulation we expected it to me very poorly insulated. The new celotex and underfloor heating wet system then screed over the top. The floor is to be tiled once extension is completed. Can anyone advisehow I can insulate the old floor it needs some form of insulation for sure? And anyone advise on the Under floor heating ideas? Ive attached a picture for you all to see