I have just had my house insulated both in the walls and loft. But I have found that I have a lot of condensation or damp all over my loft. I think I have some venting in the loft but this does not work. Can you please help me to sort this out?
If you have condensation then you don;t have enough ventilation..... Or you have a leak. Your loft needs adequate ventilation, otherwise all the warm air rising through your house will condense on the cold roof surfaces and turn to water droplets. The idea of loft insulation is to trap the warm air in the rooms below the loft. Not the loft itself. Your loft should be cold and well ventilated. Whoever provided the insulation should have advised or installed adequate ventilation. It may be as simple as pulling some of the insulation away from the very edgs of you loft to reveal the orginal vents.
the ventilation may or maynot be adequate just remember opening the loft hatch introduces a horendous amount off moist warm air that immediatly drops its water content try leaving for a week and immediatly that you open the hatch look and if you have more than token dripping you need more ventilation big all
Where there was a cavity wall, the external wall ventilators would allow air to enter and circulate the cavity which would also ventilate the loft space. When loft insulation was introduced, it was not widely appreciated at that time that by pushing the insulation tight into the eaves and blocking off this vital air circulation supply would have a harmful effect. By introducing eave vents, (http://www.thediyworld.co.uk/roofspace.html) air can bypass the insulation at this point, but as new buildings now have the cavity blocked with insulation, (as you have also done), the ventilation usually comes in via the soffits. If your house has soffits you can introduce these circular vents yourself.