Condensation in Conservatory roof

Hi all,

Recently bought a house with existing conservatory that was built about 4 years ago. Conservatory faces east with only morning sunshine. I have noted in the past couple of months condensation has formed within the triple wall polycarbonate roof panels (As opposed to the inner surface) that persists all the time and does not go away. Have spoken to a number of other people with similar conservatory and no one else seems to have this problem. Almost all of the roof is affected and the condensation has now formed into water droplets. Have not had any problem at all with condensation within the conservatory itself. Clearly, if the matter is not resolved soon I can expect to see green algae growing before the summer is out. Does any one know what causes it? Or what I can do about it? and if yes, how to stop it happening again.

Many thanks in anticipation

Years ago poly used to have silver tape both ends to 'seal up the sheets'. Then years later breather tape (or T-bag tape) was installed at the bottom of the sheet with the silver tape at the top of the sheet so water couldnt get in. Most modern connys now have breather tape both ends

Sometimes installers got it wrong by installing the sheet the wrong way so the silver tape is at the bottom, bretaher tape at the top and it doesn't vent/drain properly.

Sometimes it's installed correctly but at the bottom of the sheet a 'sheet closure' isn't fitted or has dropped off. This is a piece of channel that acts as a protector to the breather tape and stops moss making its way up the poly.

Has the conny roof got a steep or a shallow pitch? Where the poly meets the house, is it properly flashed with lead?

Many thanks for your prompt reply. The roof is single pitch "Lean too" style with a fairly steep slope of around 25 degrees. Its interesting you ask about the flashing as, looking at it from ground level outside, it seems fine. Then when I go inside and look at the roof again I realise the top 10 to 12 inches of the poly roof where it abuts the house and beneath the flashing is completely free from condensation right across the width. But from there down it covers virtually the whole of the remainder. I hope this helps

Mike