Hello everyone,
I have already tried searching but couldn’t find the right information. Therefore, I kindly ask for your help with my questions.
I want to insulate our new "garden house" (1 workshop room with 2 windows, 6 square meters (65 square feet), 1 storage room, 4 square meters (43 square feet), each with its own door). The building rests on pier foundations with 10x10cm (4x4 inches) posts, 3 continuous horizontal battens, and overlapping larch wood cladding. The floor is paved.
1.) For the floor, I was recommended to build a substructure from KDI-treated wood on rubber pads. Directly on the paving, XPS boards should be placed, slightly lower than the substructure (to allow air circulation). OSB panels are planned to be screwed on top of the substructure as the floor surface.
2.) Due to space constraints, the walls and ceiling must be insulated from the inside. With conventional insulation using mineral wool, a vapor barrier would typically be required. However, since various mounting brackets/hooks will be screwed to the walls, I am concerned about damaging the vapor barrier. Therefore, I would like to insulate here using XPS as well. I plan to glue the XPS directly onto the cladding, in a similar way to the floor. Then, OSB panels would be screwed onto the existing battens/posts.
I now have the following questions:
Regarding 1.) Is an additional membrane or similar required beneath the substructure or the XPS boards?
Regarding 2.) My biggest concern is mold growth. It wouldn’t be a problem if it doesn’t get too warm and humid inside. Is there any issue with the planned wall and ceiling insulation using XPS? How much space should remain between the OSB panels and the insulation? Is ventilation behind the insulation necessary, or can the XPS boards be attached directly to the cladding?
Thank you very much!
Lasse
I have already tried searching but couldn’t find the right information. Therefore, I kindly ask for your help with my questions.
I want to insulate our new "garden house" (1 workshop room with 2 windows, 6 square meters (65 square feet), 1 storage room, 4 square meters (43 square feet), each with its own door). The building rests on pier foundations with 10x10cm (4x4 inches) posts, 3 continuous horizontal battens, and overlapping larch wood cladding. The floor is paved.
1.) For the floor, I was recommended to build a substructure from KDI-treated wood on rubber pads. Directly on the paving, XPS boards should be placed, slightly lower than the substructure (to allow air circulation). OSB panels are planned to be screwed on top of the substructure as the floor surface.
2.) Due to space constraints, the walls and ceiling must be insulated from the inside. With conventional insulation using mineral wool, a vapor barrier would typically be required. However, since various mounting brackets/hooks will be screwed to the walls, I am concerned about damaging the vapor barrier. Therefore, I would like to insulate here using XPS as well. I plan to glue the XPS directly onto the cladding, in a similar way to the floor. Then, OSB panels would be screwed onto the existing battens/posts.
I now have the following questions:
Regarding 1.) Is an additional membrane or similar required beneath the substructure or the XPS boards?
Regarding 2.) My biggest concern is mold growth. It wouldn’t be a problem if it doesn’t get too warm and humid inside. Is there any issue with the planned wall and ceiling insulation using XPS? How much space should remain between the OSB panels and the insulation? Is ventilation behind the insulation necessary, or can the XPS boards be attached directly to the cladding?
Thank you very much!
Lasse
Do you really think this will dry?
Here is a photo where my wife had placed something in the corner.
I first unscrewed the bottom board. Now it’s better ventilated, but you still can’t place anything there.
Additionally, I see the main problem with the moisture. Because I work, breathe, sweat, and emit heat, the existing air is warmed and takes in more moisture. But the shed and everything inside it don’t warm up as quickly as the air does. So the warm, now more humid air cools down on all the cold surfaces and condensation forms. Even if I turn on a fan heater or radiator, the contents of the shed won’t warm up that fast. In any case, this creates extra moisture that needs to be removed. Or am I misunderstanding something?
Maybe my approach to insulation is completely wrong and it’s more about air supply and exhaust ventilation. But the floor made me a bit suspicious...
Thanks and best regards
Lasse
Here is a photo where my wife had placed something in the corner.
I first unscrewed the bottom board. Now it’s better ventilated, but you still can’t place anything there.
Additionally, I see the main problem with the moisture. Because I work, breathe, sweat, and emit heat, the existing air is warmed and takes in more moisture. But the shed and everything inside it don’t warm up as quickly as the air does. So the warm, now more humid air cools down on all the cold surfaces and condensation forms. Even if I turn on a fan heater or radiator, the contents of the shed won’t warm up that fast. In any case, this creates extra moisture that needs to be removed. Or am I misunderstanding something?
Maybe my approach to insulation is completely wrong and it’s more about air supply and exhaust ventilation. But the floor made me a bit suspicious...
Thanks and best regards
Lasse
P
pffreestyler4 Sep 2019 10:53Is it possible to retrofit a concrete slab floor in that shed, or would that be disproportionate?
I know many people with this type of shed who have the same problems and haven’t found a proper solution yet. According to an acquaintance, a common mistake is that the gap between the wood and the paving is too small.
I haven’t encountered these problems with sheds that have a concrete slab floor.
I know many people with this type of shed who have the same problems and haven’t found a proper solution yet. According to an acquaintance, a common mistake is that the gap between the wood and the paving is too small.
I haven’t encountered these problems with sheds that have a concrete slab floor.
Hello pffreestyler,
I had also considered a concrete slab back then, but the builder thought it was disproportionate. Now it’s even more complicated because the shed is right next to the house and the paving is already in place...
Are you referring to the distance between the wooden formwork and the paving? Or, if I build a floor, the distance between the substructure/OSB board and the paving?
Thanks!
I had also considered a concrete slab back then, but the builder thought it was disproportionate. Now it’s even more complicated because the shed is right next to the house and the paving is already in place...
Are you referring to the distance between the wooden formwork and the paving? Or, if I build a floor, the distance between the substructure/OSB board and the paving?
Thanks!
P
pffreestyler4 Sep 2019 13:26I meant the current condition. If the spacing is too narrow, the air circulation apparently isn’t sufficient. At an acquaintance’s place, the wood at the bottom is already starting to mold. They have also discussed a concrete slab, but they wanted to redo everything then. However, nothing has happened so far.
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