Damp loft insulation

Hello Chris, When insulation gets damp/wet it never properly dries out properly. Insulation is designed to trap air movement, without air movement the insulation will struggle to dry out if at all. I would assume the last leaks have caused the insulation to get damp & wet or at some point their was condensation build up in the loft. I would advice to double & triple check theirs definitely no condensation build up or leaks, then replace all the damp and wet insulation with new insulation. This is a job you can do yourself if you just want standard mineral wool(fibreglass insulation) You need a build up of 300mm to meet regulations and not to receive a strongly worded letter from insulation Britain or Greta thunberg… 150mm going one way then another 150mm going the opposite direction, basically cross hatching the two, the first layer should be cut right between the ceiling joists. You can cut the insulation with a normal hand held wood saw, keep in its packaging & measure, mark, then cut. That keeps it tight and doesn’t expand and go everywhere, whiles your trying to mark and cut it once you cut the roll up into sizes that fit your ceiling joist spaces, you can then take the packaging off and roll away. Make sure your wearing a mask a jumper & gloves whiles your bagging up the old insulation, new insulation isn’t half as bad as the old stuff for being itchy, you can wear this with the new stuff if you find it itches your skin and throat. Hope this helps. Regards Frankie BT Roofing Services Limited Is it possible then that maybe there’s a bathroom extraction fan going into loft space that isn’t venting properly, eg flexible tube has come off at one end or split in it? If this happens even a loft space ventilated to current the standards, will be overwhelmed and cause condensation build up. Are you drying excessive amounts of clothes inside on clothes airers, or using a tumble dryer that isn’t ventilating outside? Is their excessive amounts of people living in the property, eg family of 5+ in a 2/3 bedroom house, are you having excessive long showers exceeding 15 minutes? Has your dry ridge system been installed properly, on an old roof like yours they should have cut the bitumen membrane at the ridge to ease air movement. If nobody lives in the house, the roof must still be leaking or as I stated in my first reply the insulation is wet from an old leak/condensation problem and isn’t drying out. Insulation once wet will struggle to dry out properly, I would advice putting some paper towels down over the insulation but not touching it so it can’t absorb the moisture out from it, use like chicken wire or something so it suspended above it and see if they get damp/wet. If the paper towels aren’t wet after a month then you know the insulation isn’t drying out from a past leak/condensation problem, thus just replace all the insulation. If they are wet then you know the roof is leaking somewhere. I don’t think it’s possible with your theory, otherwise everyone would have the same issue in their loft, soffits & fascia vents are tested in labs to all weather conditions to test they don’t let the weather in but only allow air flow into the roof space.

Without looking it's really impossible to say for sure. Most likely condensation created by the weather, your loft will still receive heat when the outside weather heats up the roof that will penetrate through just the same as cold. also the roof felt is 50yrs old its recommended by insurance company's that you replace this every 20-25 yrs as it degrades goes brittle & leaks, by adding a dry ridge system it has achieved nothing other than add holes to the felt as the felt under neath is un-breathable if the ridge was replaced because it was leaking that means the felt was compromised and should have been replaced at the same time. Good luck Alex

You mentioned you only had soffit vents, which is only venting the eaves by fitting a dry ridge system your allowing continuous AIRFlow throughout the loft space and maybe a few tile vents aswell. By adding more and more insulation your loft will just sweat Thank you Falcon roofing and property maintenance ltd