I have built with trusses approximately as shown in the picture, the idea was to have a cold storage in the attic. But then it occurred to me that maybe I could distribute the insulation on both the roof and the floor, from the attic space, and get a slightly warmer attic space. So instead of raising the floor, put that volume in the roof instead, where the trusses already take up space.
My first thought is that if you insulate up in the ceiling, the space will become warmer, thus you will have warm air moving into the insulation and cooling down as it approaches the outer roof. The warm air contains more moisture than cold, and thus you get condensation on the inside of the outer roof.
So either the insulation you put in the ceiling must be tight so that air cannot wander outwards, or you need a barrier like plastic sheeting to prevent the air from moving. I've seen that spray insulation that they spray between the roof beams, I suspect it's tight enough that it might work, but I wouldn't use regular fiberglass or such. So I'd probably be cautious about trying unless you get an answer from someone who KNOWS a specific method that works well.
Well, I mean, I don't want exposed insulation in the space, of course, there should be panels on all surfaces. Air gap against the outer roof, etc.
I might have expressed myself unclearly. The question is really whether you can account for the thickness of the insulation, even if you split it into two places with an attic space in between. Just as much as 380 mm in the floor, can I choose to have 245 mm in the floor and 135 mm in the ceiling?
In terms of insulation, it will be the same. The tricky part will be how to create the air gap and its ventilation. The air gap often ends up at the top of this attic and is ventilated through the gables. But it can surely be solved if one is determined!
The air gap should be uncomplicated: Some boards and a masonite panel from the insulation stop up to the ridge and vents out under the tiles I think. There is something they call mögelstopper, maybe they can be used at the ridge.
The air gap should be uncomplicated: Some strip and a masonite board from the chip stop up to the ridge and vents out under the tiles, I think. There is something they call mögelstopper, maybe they can be used at the ridge.
Yes, you should somehow have a channel at the top that the air gaps are led to and then vent the air there. Maybe it works with those under the tiles. Alternatively, you have a smaller "wind" at the top leading towards the gables, but then it eats up a bit of ceiling height.
Feel free to post pictures of how the solution turns out! Interesting problem there.
You're absolutely right!
When we built, we made a so-called climate attic.
We have 290 mm of mineral wool insulation in the interior ceiling and 100 mm of foam board above the boards,
so together 390 mm of insulation upwards. The attic is unventilated.
It's now 3.6°C outside and >95% RH, in the attic (unheated) we have 7.8°C and 66% RH.
Down in the living space, we have 22°C 28% RH (which is actually too dry). Heating LLVP.
How do you solve the air gap in the sections that do not end in the eaves? I have the build at an angle, so at the valley it's tight...
Could you put a vent also at the bottom?
Strip said:
