Condensation in new insulated Attic - conflicting opinions.

tom23

Hi All,

I appreciate this topic has possibly been covered multiple times, but I have a problem and I'm trying to understand it and why it's happening. I got my attic insulated in October by a reputable company, I couldn't fault with them for anything. I also had the front cavity wall pumped with styrofoam balls.

Before Christmas I noticed a lot of condensation in Attic and I sent an email to Insulation company who told me that some condensation is to be expected. On another visit I was alarmed at just about how much there was. So they sent out their construction surveyor who felt that some parts of the job could have been done better and they would fix it. But he then informed me that I had a roof leak and also my Ensuite Extractor Flexi pipe had become detached from the roof (It was actually their fault as they wrapped it in rock wool and the weight of it caused it to disconnect).

I called in a Roofer. He inspected the roof inside and out. Took off the tiles where the surveyor had told there was leak. This was around a second roof vent, which was never used. The bitumen membrane was hanging down around the vent like someone punched through the roof. The Roofer pulled off all the roof tiles above this but could see no evidence of a leak. He traced down the rafter which lead to the Skylight tunnel which was wrapped in Rockwool by the insulation Company and tied. This rockwool was very very wet. So he went back outside, removed all tiles around the Velux window and discovered the flashing was bent back and there was a lot moss and muck etc. He made good again and fixed everything back.

He has suggested that if this was his roof he would take off all the tiles, replace the membrane with a breathable one. Replace the lats with pressure treated ones, put in some more roof vents for extra circulation and put back the tiles. I was all set to do this but he has since said he is not completely convinced it will solve my problem, he discussed with another roofer who had tacked a similar job but the condensation still remains.

So I am waiting on the Insulation company to come out and replace wet insulation and to fix back up extractor fan pipe. So I am at loss what to do. I will post up some photos and video if possible of condensation.

If anyone has had similar problem Id love to hear how you fixed it...

Thanks

MicktheMan

Looks like condensation from those pics. Also likely to be (worst) on the north side of the roof.

You need to improve cross ventilation up there. Also, ensure all extractor fan ducting is properly connected and exiting the attic.

Chances are also that there may be excess moisture in the internal air in the house too.

Gusser09

https://www.boards.ie/discussion/2058331796/condensation-in-new-insulated-attic-conflicting-opinions

Its a difficult and complex fix.

Id start by adding more tile vents for a start and work from there.

mosii

Hi, by the looks of your first photo you have the insulation pushed in around the eves ,pull back the insulation around a foot so as to promote ventilation .Also is your heating system fe tank in the attic ?if so make sure that it has a cover on it. Good luck.

Damien360

I had a very similar problem and have it solved. 2 story semi d.

We got the house pumped and the attic insulated with new rock wool one summer. Extractor in bathroom out through attic and then out eave vent. The problem didn't arise until the winter. Exact same as your last picture with the beams getting wet and wet rock wool. Wet boxes in attic used for storage.

First, the hose for extraction was barely attached and it was actually on top of the rock wool. Clamped it down correctly and put the rock wool over the hose to try minimise recondensed steam into pipe.

Second, roof vents at about half height in attic along the whole length. 3 each side of house. Now the important part. I found one year I still had issues but then removed items in the attic to never be above the line of the vents (I have a shallow attic which you cannot stand up in). That allows air flow across the attic and that has fixed it. Even in the coldest weather it's fine.

One to also watch is the space directly above your hotpress. I got conflicting advise here. I was told I should ensure this heat does not escape into the attic to minimise issues but my plumber told me to leave it clear of rock wool as it is almost directly under the water tank in the attic and I don't want that freezing. Either way, I followed the plumber advise and still don't have condensation issues.

Hope this helps.

Damien360

Closer look at the pics. Have you rock wool down at the eaves covering vents in eaves ?

listermint

Blocked all original ventilation. This is the result.

mickdw

Have they really blocked all the soffit vents?

Gusser09

Soffit vents may not be suitable for newly insulated attics brought up to standard.

Op you could try felt lap vents. Quick to install and you can do it yourself. Cheap fix if it works.

tom23

insulation company are coming back out next week to ‘fix’ some of the issues. I am collecting insulated duct pipe for the extractor fan tomorrow. There are also extra vents in the soffits that were out there by the insulation company. I’m hoping next week tells a new story.

Regardless I plan to put more vents in the roof. Thanks for all the replies folks much appreciated

Andrewf20

https://www.boards.ie/discussion/2058331796/condensation-in-new-insulated-attic-conflicting-opinions

As already said, remove insulation from being stuffed into the eaves. Also try this trick as per photo below. I found that creating a gap in the layers of felt creates a bit of wind in the attic. I just used used old blocks of kids lego myself. Also, assess if enough rockwool is put down to reduce heat getting through from downstairs, ideally 300mm thick.

https://www.diynot.com/diy/attachments/img_20181228_145922081-jpg.177201/