Dear forum members,
We will be receiving a prefabricated house at the end of the year. The floor of the unfinished attic will remain open, meaning the ceiling joist structure will be visible and not yet walkable.
We would like to make the attic floor walkable by installing cross battens and then laying floorboards on top, so that we can store a few items up there.
I hope someone here has experience with this and can advise me on the spacing for the battens and the thickness of the floorboards needed to ensure the floor is safely walkable.
Thank you in advance for all your responses.
We will be receiving a prefabricated house at the end of the year. The floor of the unfinished attic will remain open, meaning the ceiling joist structure will be visible and not yet walkable.
We would like to make the attic floor walkable by installing cross battens and then laying floorboards on top, so that we can store a few items up there.
I hope someone here has experience with this and can advise me on the spacing for the battens and the thickness of the floorboards needed to ensure the floor is safely walkable.
Thank you in advance for all your responses.
When the roofer was constructing the roof frame, I had them place battens for the counter-battening and OSB panels in sufficient quantity directly onto the rafters. This is much easier than carrying the panels and battens up later through the pull-down attic ladder. Unfortunately, at that time I didn’t yet know that tongue-and-groove boards would have been better.
I installed the counter-battens spaced about 50 cm (20 inches) apart on the rafters. On one side, I then laid OSB panels up to the attic ladder opening (about 30% of the attic floor). I left a gap of approximately 5 cm (2 inches) around the perimeter (next to the masonry) to allow air circulation. After one year, this existing space is still more than sufficient. I will only install the remaining panels when I need additional space.
Regarding thickness: Our OSB panels are 22 or 26 mm (7/8 or 1 inch) thick. They easily support the stack of spare tiles.
Edit: We have no mold.
I installed the counter-battens spaced about 50 cm (20 inches) apart on the rafters. On one side, I then laid OSB panels up to the attic ladder opening (about 30% of the attic floor). I left a gap of approximately 5 cm (2 inches) around the perimeter (next to the masonry) to allow air circulation. After one year, this existing space is still more than sufficient. I will only install the remaining panels when I need additional space.
Regarding thickness: Our OSB panels are 22 or 26 mm (7/8 or 1 inch) thick. They easily support the stack of spare tiles.
Edit: We have no mold.
Jochen104 schrieb:
Edit: We do not have any mold.But you have also installed counter battens to allow air circulation underneath, and so far you have only installed 30%.
K
Knallkörper17 Oct 2016 15:17I am facing a similar question. For the roof decking, I have already chosen tongue-and-groove boards because they allow better "breathability," and I will probably use tongue-and-groove boards for the attic floor as well. However, I see a flaw in the logic here: there is a vapor barrier under the insulation, so a minimal ventilation space above (like with the joists) should be sufficient, right?
The advantage of OSB boards is apparently much faster and easier installation. The surface is probably also smoother, which would allow a higher-quality floor covering to be laid later on.
Question: Should a counter-batten layer also be installed under the tongue-and-groove boards, and if so, why?
The advantage of OSB boards is apparently much faster and easier installation. The surface is probably also smoother, which would allow a higher-quality floor covering to be laid later on.
Question: Should a counter-batten layer also be installed under the tongue-and-groove boards, and if so, why?
Normally, there is a vapor barrier beneath the insulation. The question is whether it is 100% airtight.
At least in our case, the vapor barrier is fixed to the walls. Therefore, moisture could potentially rise through the walls. Additionally, you have cable penetrations, wall connections, and joints/holes in the membrane where there is a risk that it is not completely airtight.
At least in our case, the vapor barrier is fixed to the walls. Therefore, moisture could potentially rise through the walls. Additionally, you have cable penetrations, wall connections, and joints/holes in the membrane where there is a risk that it is not completely airtight.
B
Bieber081517 Oct 2016 16:36Knallkörper schrieb:
There is a vapor barrier underneath the insulation, so a minimal ventilation to the top (like Jochen’s setup) should be more than enough, right? IMHO: Hardly any moisture will pass from the interior into the insulation (since the house is airtight), but the insulation is still exposed to the atmosphere above the OSB boards. Eventually, the dew point will be reached somewhere (at night, during weather changes), and once you have mold in there...
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