ᐅ Insulation Installation for the Top Floor Ceiling (Attic Space)

Created on: 7 May 2020 21:07
T
tiborb
Hello everyone,

I am planning to insulate the top floor ceiling, approximately 110 sqm (1,184 sq ft) of the old building built in 1972 on my own.
The semi-detached house has two full floors (ground floor, first floor) and a basement.

The 110 sqm (1,184 sq ft) will be covered as follows:
  • 70 sqm (753 sq ft) non-walkable
  • 40 sqm (431 sq ft) walkable as storage space

All without an additional vapor retarder because the ceiling is concrete.

Questions:

1) Do I need a vapor barrier because of the concrete ceiling?
2) Which material and thickness would you recommend for the non-walkable and walkable areas?
3) What price range should I expect for the insulation material for these two areas?
4) What should I definitely pay attention to during installation? Maybe there is a good link with instructions?

Thank you!

Best regards
J
Joedreck
8 May 2020 12:52
I don’t have personal experience with the finished panels. However, the manufacturer does specify whether they are walkable or not, so you can rely on that.

And no, I didn’t mean 12mm but 12cm (5 inches).
You want to insulate the upper floor ceiling. Partially walkable. The non-walkable part is straightforward. For the walkable part, you need to come up with a solution.

You can take the finished panels, lay them on your concrete ceiling, and everything will be great – seriously. Although it will cost you.

Then there is the self-build option. The problem is that you need to create a load-bearing insulation layer of about 24cm (9.5 inches) thickness. Just mineral wool alone won’t suffice. So you could:

Get 12cm (5 inches) thick joists. Stand them upright on the concrete floor. Place mineral wool batts between them. Then cross 12cm (5 inches) thick joists on top again, with more wool between.

Finally, add tongue-and-groove boards as the walkable surface.

I honestly can’t say what the final cost of this solution will be. You’ll have to calculate that for yourself.

I purposely did not design my attic as a storage space, so it is completely non-walkable.
T
tiborb
8 May 2020 16:18
Now I understand you. Thank you.
That means I could generally use the affordable fiberglass insulation batts for the areas that are not walkable, right?
And if I build the beams and boards myself, I could use it then as well, right? Because the stone wool is considerably more expensive than the fiberglass...

Thanks
J
Joedreck
8 May 2020 22:02
Yes, you can. Although I personally chose stone wool insulation and am quite particular about it. Just make sure to do the calculations beforehand. If it takes you two weeks to complete, saving €200 probably isn’t worth it.