Laying floor in the attic

[Nygge72]

Hi, I have a house from '72 with a cold attic. I'm a bit interested in laying walkable flooring up in the attic. Today, there is only a middle path laid with chipboard.

If one wanted to expand the walkable area, how should one proceed to avoid creating moisture/problems?

Am I thinking correctly that perhaps I should lay joists on top of the trusses, and on top of that walkable material, to create an air gap between the current insulation and walkable material, or is the air gap completely unnecessary?

Today, paper lies over the insulation. Will I ruin the insulation's ability if I put joists/walkable material on the trusses, as they are under the paper?

 

[TheGame]

I was planning to lay flooring, but I haven't done more than "making do with what I have" and putting it where I needed flooring.
Eventually, I felt it was overkill to do flooring everywhere.
I've made it from sheets or boards only.

 

[KnockOnWood]

Today, the paper is over the insulation. Will I destroy the insulation's effectiveness if I install joists/walkable on the truss joists, as they are under the paper?

How far below the insulation's protective paper are the truss lower chords?
If there's a significant height difference, you compress the insulation, and it insulates worse if you lay floorboards directly against the trusses.
So, what is the height difference?
If it's more than a centimeter, I would shim the trusses to come up to the level of the insulation, and then lay longitudinal floor planks across the truss direction. Like these:

(These are in southern Halland, so you need to find similar ones in your area)

By the way, how high are the truss lower chords? And how thick is the insulation?
You might want to take the opportunity to insulate a bit more before you cover the floor structure.

 

[Nygge72]

How far below the insulation's protective paper are the truss's lower frames?
If there's a significant height difference, you'll compress the insulation, and it will insulate worse if you lay floorboards flush against the trusses.
So what's the height difference?
If it's more than a centimeter, I would strap the trusses to match the insulation height, and then lay longitudinal floorboards across the truss direction. Like these:
[image]
(These are available in southern Halland, so you'll need to find similar ones in your area)

By the way, how high are the truss's lower frames? And how thick is the insulation?
You might want to add some more insulation before closing up the joists.

Thanks for the tip. I'll check that out.

The insulation is not more than about 20, I would guess, as that's roughly what they used around -72. I'd like to insulate a bit more, but at the same time, I've read that houses with cold attics can develop significant moisture/mold problems with additional insulation, and now the attic is still in great shape (as far as I can tell) after over 50 years, so I'm a bit afraid of changing that. At the same time, I do measure the moisture up there, and the recent warmer climate has made the humidity borderline, in my opinion.

So we'll see in a while, as I want a longer measurement period to see if it continues like this. If so, I'll probably need to make some adjustments to reduce the humidity a bit, and then additional insulation might be considered with

 

[MrDizzy]

Thanks for the tip. I will check it out.

The insulation is no more than about 20, I would guess, since that's roughly what was used in '72. I'd like to insulate a bit more, but at the same time, I've read that houses with cold attics can have significant moisture/mold problems with additional insulation, and currently, the attic is still great (as far as I can see) even after more than 50 years, so I'm a bit afraid that I would change that. At the same time, I am measuring the humidity up there, and the warmer climate of recent times has also caused the humidity to be on the edge, I think.

So we'll see in a while since I want a longer measurement period if it continues like this. If so, I will need to address it to reduce the humidity a bit, and then it might be time to consider additional insulation as well.

Yep, I got the advice from the inspector when I bought this kitchen, which is from '62, not to add insulation to the cold attic. If I want to do that in the future, I would need mechanical ventilation or even better, FTX as well as something equivalent to "TrygghetsVakten Vind" to really ensure there is no moisture.

I have installed FTX and am currently ordering a Raspberry Pi to build my own version of trygghetsvakten just for fun.

Once I've got it up and running, I'll probably go ahead with the additional insulation.

 

[Nygge72]

Yep, Got the advice from the inspector when I bought this kitchen, which is from '62, NOT to add extra insulation to the cold attic. If I want to do it in the future, I would need mechanical exhaust or even better FTX and something equivalent to "TrygghetsVakten Vind" to really ensure no moisture develops.

I have installed FTX and am currently ordering a Raspberry Pi to build my own version of the TrygghetsVakten just for fun.

Once I have it up and running, I will probably add extra insulation.

Yes, it's the TrygghetsVakten I'm looking into as well in case I need to address the issue. Exciting to build it yourself