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
Good tip!
I’ve now also received the advice to use a wooden substructure on rubber pads, with a PE foil and OSB panels. The bottom boards should be removed (see photo) to install a kind of ventilation grille. Then place ventilation grilles just above the floor and just below the roof. Possibly insulate the ceiling as well. I’ll test to see how effective this is...
Thanks to everyone for the help!
I’ve now also received the advice to use a wooden substructure on rubber pads, with a PE foil and OSB panels. The bottom boards should be removed (see photo) to install a kind of ventilation grille. Then place ventilation grilles just above the floor and just below the roof. Possibly insulate the ceiling as well. I’ll test to see how effective this is...
Thanks to everyone for the help!