Hoping someone can help me with this question. We have had cavity wall insulation and the company who did this drilled through the walls in the loft from the inside when filling the top of the house walls. I have noticed that none of the holes have been filled and I can see the insulation. I was wondering if they should have been filled with mortar? The reason I ask this is because we are experiencing lots of condensation build up on the roof felt which is dripping everywhere. I was wondering if warm air in the cavity is escaping through the holes and causing condensation when it meets the cold roof? We have never had this problem in the last 10 years of living here, so we are trying to pin point possible causes. Thank you to anyone who can advise.
you need to vent the attic space,the insulation must be clear from the eaves to allow air to flow in.If there is no way air can enter from the eaves then you need to install either soffit vents or tile/slate vents,mortar over the holes wont do anything.
Thank you welsh brickie for the advice. The house has vents in the soffits at the front and back of the house so I've been in the loft to look at the insulation and inspect the soffits. When I rolled back a couple of the insulation rows I found that there was insulation in the soffits. The insulation is different than that rolled out in the loft. I thought that the soffits had to be clear to allow air flow in and out, so not sure why it is in there. I'm assuming that with us now having the walls insulated the loft needs increased air flow to eradicate condensation. Should there be insulation in the soffit?