1

We have a pitched roof (1971 house, The Netherlands) which consists of (outside to inside):

  1. Tiles
  2. 2cm PUR insulation
  3. 2cm wood

We asked a few companies for quotations to improve the insulation (currently Rc=0.8).

Company 1 is suggesting to add rockwool to the inside, while company 2 says that any insulation on the inside will lead to condensation issues.

Are there any options for adding insulation on the inside of the roof in this case?

Edit: picture of the roof material: Picture of the roof material

  • Hello, and welcome to Home Improvement. Good question; let's see if one of our pros can help. And, you should probably take our tour so you'll know how best to participate here. – Daniel Griscom Jul 20 at 15:09
  • Can you add a picture of the current insulation please? – The Evil Greebo Jul 20 at 15:09
  • I have added a picture to the post of a slice of the roof (on top are the roof tiles). – Ruben Jul 21 at 8:46
0

If you have your insulation on the roof sheathing and the roofing covers it, presumably there is adequate ventilation for the attic so condensation hasn't been an issue already since the foam is non permeable.

Another assumption I will make is that you have an attic space that would be a conditioned space since the roof insulation is above that.

With those parameters in mind you should be able to add as much insulation you need or like as long as it is permeable like the rock wool suggested in your post, fiberglass, or other loose material that may be available for you.

  • Thank you for your answer Jack. The attic is heated in winter (but not cooled in summer other than opening windows). So if I understand correctly, we could add for example rock wool, can we then cover with plasterboard + paint? Or would that not be permeable enough? – Ruben Jul 21 at 8:49
  • Evidently I don't understand quite yet the construction of the roof/ rooms. I figured there already was sheetrock finish on the ceilings of the rooms to support the rockwool if added, but it sounds as if you are looking at the backside of the roof sheathing, so any added insulation needs to be supported... Yes the added layers are permeable enough to all moisture to pass through. – Jack Jul 23 at 14:19

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.