Building insulated wooden floor (on uninsulated concrete) and insulated walls in an old outhouse.
Hello,
I am currently furnishing a room in an old outbuilding; the floor is currently an old uninsulated concrete slab with various depressions. It's not a room intended for an indoor climate, but possibly to keep it frost-free at least. It's going to be a small workshop area where I can work on mopeds and bicycles, so no running water and no requirement for 20-degree heat.
The floor is about 3.4x4.2 m with a "cross" in the middle where the right side of the room has two depressions about 30 cm deep and a wall between them about 13 cm wide, and the left side has depressions about 4-6 cm deep with a wall about 6 cm wide.
My plan for the floor is to lay ground insulation polystyrene (XPS) boards directly on the concrete about 50-60 mm with 45 mm battens in between leveled and screw 15 mm plywood onto the battens directly above the insulation. Then paint with some suitable paint to make it reasonably tight.
Over the larger depressions on the left side, I thought of first framing with 45x145 beams and propping up the remaining 15-20 cm with an upright beam in the middle of the depression. I will lay the insulation directly under the plywood, by placing a batten on the beam against which it can rest. There will thus be an empty space under the insulation. Are there risks with that?
The walls consist partly of 60 mm plank wall; how much additional insulation is required on these? I read somewhere that wood insulates well.
I planned for the remaining walls to go, from the outer panel's perspective, with windproof paper, 95 mm wool insulation, 11 mm OSB board, and then paint with suitable paint. From what I've read, plastic shouldn't be needed in spaces not exposed to water and high temperature differences.
The ceiling currently consists of 165 mm sawdust insulation except for a part where it has been removed due to an older water damage; there, I plan to replace it with 165 mm wool.
I live in West Sweden and rarely have extended periods below -10 degrees in the winter.
Tips and ideas are welcome; this should be done as cheaply as possible since the entire outbuilding will likely get a major renovation in 5-15 years.
Best regards, Erik
I am currently furnishing a room in an old outbuilding; the floor is currently an old uninsulated concrete slab with various depressions. It's not a room intended for an indoor climate, but possibly to keep it frost-free at least. It's going to be a small workshop area where I can work on mopeds and bicycles, so no running water and no requirement for 20-degree heat.
The floor is about 3.4x4.2 m with a "cross" in the middle where the right side of the room has two depressions about 30 cm deep and a wall between them about 13 cm wide, and the left side has depressions about 4-6 cm deep with a wall about 6 cm wide.
My plan for the floor is to lay ground insulation polystyrene (XPS) boards directly on the concrete about 50-60 mm with 45 mm battens in between leveled and screw 15 mm plywood onto the battens directly above the insulation. Then paint with some suitable paint to make it reasonably tight.
Over the larger depressions on the left side, I thought of first framing with 45x145 beams and propping up the remaining 15-20 cm with an upright beam in the middle of the depression. I will lay the insulation directly under the plywood, by placing a batten on the beam against which it can rest. There will thus be an empty space under the insulation. Are there risks with that?
The walls consist partly of 60 mm plank wall; how much additional insulation is required on these? I read somewhere that wood insulates well.
I planned for the remaining walls to go, from the outer panel's perspective, with windproof paper, 95 mm wool insulation, 11 mm OSB board, and then paint with suitable paint. From what I've read, plastic shouldn't be needed in spaces not exposed to water and high temperature differences.
The ceiling currently consists of 165 mm sawdust insulation except for a part where it has been removed due to an older water damage; there, I plan to replace it with 165 mm wool.
I live in West Sweden and rarely have extended periods below -10 degrees in the winter.
Tips and ideas are welcome; this should be done as cheaply as possible since the entire outbuilding will likely get a major renovation in 5-15 years.
Best regards, Erik
Insulating the floor internally is not a good idea. You will get moisture migrating inwards, and with wooden joists on the floor, it will result in mold.
Very little heat escapes downwards, so it’s better to level the floor with self-leveling compound and focus on the walls instead.
Feel free to use wood fiber insulation, and you will likely need at least 150 mm but preferably at least 200 mm. The roof sounds like a good plan.
I believe Bauhaus has some insulation that withstands moisture better as well...
Very little heat escapes downwards, so it’s better to level the floor with self-leveling compound and focus on the walls instead.
Feel free to use wood fiber insulation, and you will likely need at least 150 mm but preferably at least 200 mm. The roof sounds like a good plan.
I believe Bauhaus has some insulation that withstands moisture better as well...
OK, it will be almost 2 cubic meters to fill up if everything is to be even, so I probably need to start with some concrete. Or perhaps macadam.
That's why I wanted to build a raised floor instead. Can the moisture problem be solved with a Platon mat? Or just skip the insulation in the floor and lay some sill gasket or similar under the joists that will be in direct contact with the concrete?
But do you really need so much insulation in the walls of a space that will only be heated a little or maybe just when something is being done? At the same time, it's "only" 165 in the ceiling, where most of the heat is likely to escape?
Best regards, Erik
That's why I wanted to build a raised floor instead. Can the moisture problem be solved with a Platon mat? Or just skip the insulation in the floor and lay some sill gasket or similar under the joists that will be in direct contact with the concrete?
But do you really need so much insulation in the walls of a space that will only be heated a little or maybe just when something is being done? At the same time, it's "only" 165 in the ceiling, where most of the heat is likely to escape?
Best regards, Erik
No one else with any more input?
From what I've read, there are people who insulate summer cottages, "friggebodar", and similar with less insulation than what I'm planning to use here.
How can I achieve a flat floor most easily without having to chisel and cast a lot?
Best regards, Erik
From what I've read, there are people who insulate summer cottages, "friggebodar", and similar with less insulation than what I'm planning to use here.
How can I achieve a flat floor most easily without having to chisel and cast a lot?
Best regards, Erik
Regarding the floor. What happens if you lay a framed floor with felt paper under the joists but cut ventilation holes in the joists so that they're not completely enclosed, and then place building paper between the plywood sheets and the joists so that the concrete slab can ventilate out to the outdoor air via the air gap in the walls?
How close must I place the noggings in the floor now that it will be without insulation?
Does anyone else have any more suggestions or opinions?
Best regards, Erik
How close must I place the noggings in the floor now that it will be without insulation?
Does anyone else have any more suggestions or opinions?
Best regards, Erik