Water droplets inside roof tile underlay.

brightondave

Hi   I had occasion to get up into the vicinity of the loft hatch today, I moved a couple of full bin liners from the ladder and found they were a bit damp. I looked up at the roof area, the membrane roll that covers the tiles of the pitched roof had water droplets on and seemed to be on most of the area that I could see.    Has anybody found this sort of thing before? 
Any advice or knowledge is appreciated.    Thanks.

stuart45

Is it a modern breather membrane, or the older type roofing felt?  The older felt didn't allow moisture out, so condensation often formed, especially when insulation started to be used.

troffasky

Lap vents inserted where the sheets overlap will improve air flow and reduce condensation.

Jeepers_Creepers

Hi Dave.

Is there loft insulation up there on the ceiling? If so, has it been pushed too far tight in to the eaves? That can block the essential air flow coming through the soffits, and condensation will be the result.

These droplets are almost certainly coming from your home - warm, moist air diffusing through the ceiling/past the trapdoor and condensing out on the very cold roof surface. That will happen, so the built-in solution is to have the loft ventilated, and this is usually via grills in the soffits. Poorly added insulation can block this flow.

How old is this house?

Mistral001

Check if you have enough through ventilation.  As has been said.  The roof space should feel draughty on a windy day.  If it doesn't then you do not have enough through ventilation.  

lg13mza

I have seen this recently in ours.  Ours isn't too bad and hasn't got to the point where it drips.  From what I've researched it isn't that uncommon, but the consensus is providing the condensation disappears after this current cold-spell and/or when the wind picks up (to improve draft through the loft) it isn't too much to worry about.  Improving air flow as suggested above will always be a benefit though.  You can add air flow cheaply by adding short lengths of waste pipe into the overlap of  felt.

Mistral001

Lack of ventilation in the roof spaces of new homes is quite common.  It can cause more than a few drops on the roof membrane and drips onto the stored Christmas tree below.  I have seen water droplets on the truss timbers of a house house less than 5 years old due to eaves vents being blocked by insulation.  In a few places I found not only droplets but wet rot on the trusses which is serious if not attended to.