Hello everyone,
we are planning to install a metal garden shed from a well-known Austrian brand in our garden. While researching the assembly and foundation, I also came across the topic of insulation. We do not intend to spend a lot of time inside or use it as a living space, but many sources online say that insulating the garden shed helps protect it against moisture and thus prevents mold.
Originally, the plan was to create a "foundation" using concrete paving slabs measuring 50x50x5cm (with gravel underneath) and simply place the shed on top. However, the manufacturer suggests adding an extra frame (4x4cm) underneath the shed, then laying 2-3cm thick XPS panels on it, and finally installing the interior floor on top of those. Why exactly 2-3cm? 4cm would also fit. But anyway.
What I have learned so far is that most of the cold comes from below. My main question now is whether these 2, 3, or 4cm thick XPS panels really make a difference or if it’s a waste of effort. I guess it’s definitely better than nothing, but will it really improve anything? The easiest option would be if the insulation is not necessary at all, but if insulating now helps avoid problems later, I’m willing to take the effort. What will definitely be included in the foundation is a vapor barrier to prevent rising moisture.
Regarding insulation, it should also be noted that the roof comes factory-prepared to easily install 3cm thick XPS panels later on. This can also be done quite easily afterward. I suspect this only makes sense if the floor is insulated as well.
we are planning to install a metal garden shed from a well-known Austrian brand in our garden. While researching the assembly and foundation, I also came across the topic of insulation. We do not intend to spend a lot of time inside or use it as a living space, but many sources online say that insulating the garden shed helps protect it against moisture and thus prevents mold.
Originally, the plan was to create a "foundation" using concrete paving slabs measuring 50x50x5cm (with gravel underneath) and simply place the shed on top. However, the manufacturer suggests adding an extra frame (4x4cm) underneath the shed, then laying 2-3cm thick XPS panels on it, and finally installing the interior floor on top of those. Why exactly 2-3cm? 4cm would also fit. But anyway.
What I have learned so far is that most of the cold comes from below. My main question now is whether these 2, 3, or 4cm thick XPS panels really make a difference or if it’s a waste of effort. I guess it’s definitely better than nothing, but will it really improve anything? The easiest option would be if the insulation is not necessary at all, but if insulating now helps avoid problems later, I’m willing to take the effort. What will definitely be included in the foundation is a vapor barrier to prevent rising moisture.
Regarding insulation, it should also be noted that the roof comes factory-prepared to easily install 3cm thick XPS panels later on. This can also be done quite easily afterward. I suspect this only makes sense if the floor is insulated as well.
W
WilderSueden19 Feb 2022 23:07A garden shed like this is rarely completely airtight, even with a floor. But if you skip the floor and place it directly on the slabs, that’s even better. This way, there is regular air exchange through the gaps between the slabs, which almost certainly prevents mold issues. As long as the foundation is sufficiently above ground level and no rainwater can enter, I wouldn’t try to make it completely airtight with plastic sheeting.
Is there air exchange through the gaps between the panels? Does it happen through the floor? How should I imagine that? I assume that without a vapor barrier, more moisture will come up from below than will go out or down through the floor. Ventilation is mainly provided by the vents integrated into the roof... I believe there are also vents in other places, but I’m not sure. If necessary, you can drill holes yourself or install a ventilation grille. All of that is relatively easy to do afterward, but any sealing or changes to the floor are more difficult.
The house will be more or less at ground level, maybe slightly above... I actually want it to stay as close to level with the ground as possible. However, the surface will have a slope so that water drains away. Therefore, except in the case of flooding (which here would have to be 80–100cm (31–39 inches) high, since the land slopes downward and has been raised), no water should get inside.
The house will be more or less at ground level, maybe slightly above... I actually want it to stay as close to level with the ground as possible. However, the surface will have a slope so that water drains away. Therefore, except in the case of flooding (which here would have to be 80–100cm (31–39 inches) high, since the land slopes downward and has been raised), no water should get inside.
G
Gartenfreund20 Feb 2022 04:16I would skip insulation as well as any kind of vapor barrier or other impermeable layer underneath the panels.
By adding insulation, you turn the garden shed into something like a thermos. Once cold air gets inside, it stays there longer. The same applies to heat. The interior is not meant to be heated, right, or did I miss something?
To prevent water from seeping in at ground level, I would place a row of panels outside with a slight slope away from the garden shed.
By the way, depending on ground conditions, paving slabs can also be laid directly on leveled soil. I did this with our garden path decades ago, and the slabs are still exactly where they were at the beginning.
By adding insulation, you turn the garden shed into something like a thermos. Once cold air gets inside, it stays there longer. The same applies to heat. The interior is not meant to be heated, right, or did I miss something?
To prevent water from seeping in at ground level, I would place a row of panels outside with a slight slope away from the garden shed.
By the way, depending on ground conditions, paving slabs can also be laid directly on leveled soil. I did this with our garden path decades ago, and the slabs are still exactly where they were at the beginning.
W
WilderSueden20 Feb 2022 16:41gardi22 schrieb:
Is there air exchange through the gaps between the boards? Through the floor? How should I imagine that? I assume that without a vapor barrier more moisture comes up from below than goes down through the floor or out. You have a layer of gravel under the garden shed that breaks the capillary action. Air that enters through any gaps can also exit through them. Don’t think of it like a house, think of it more like a shelter with walls.
Between the boards, you have either grit or sand. That doesn’t create an airtight seal. And if you also have ventilation slots in the roof, even better. I see absolutely no need or point in insulating and sealing a paved surface to make it airtight.
H
Haussuche8520 Feb 2022 17:06I think the way we did it was just right. No diamond plate flooring, but paving slabs filled with gravel. Then swept with quartz sand. Ventilation always happens in some way, so no condensation forms. The climate is fine.
I saw no reason to install a vapor barrier.
What I would have done if the house were in direct sunlight: maybe insulate the roof with polystyrene, but only because of the heat.
These houses are not comparable in terms of comfort and steel thickness to the 199-euro metal sheds from hardware stores.
I saw no reason to install a vapor barrier.
What I would have done if the house were in direct sunlight: maybe insulate the roof with polystyrene, but only because of the heat.
These houses are not comparable in terms of comfort and steel thickness to the 199-euro metal sheds from hardware stores.
G
Georgian201921 Feb 2022 09:00Haussuche85 schrieb:
I think the way we did it was just right. No corrugated metal floor, but paving slabs, all filled with crushed stone. Swept in with quartz sand. Ventilation always happens somehow, so no condensation forms. The climate inside is fine.
I didn’t see any reason to install a vapor barrier.
What I would have done if the house was in direct sunlight: maybe insulate the roof with polystyrene, but only because of the heat.
These houses are in a completely different comfort and steel thickness class compared to the 199 euro metal sheds from the DIY store. Our garden shed has 44mm (1.7 inches) thick walls. The base slab is lined with a bitumen membrane to protect against moisture from underneath, and the windows are insulated. The roof was insulated by the roofer because of summer heat (sun from above). Otherwise, without heating, the insulation only makes a 2–3°C (4–5°F) difference in winter. So, when temperatures are well below freezing, a small frost guard with 400W runs because of the Mediterranean plants that overwinter in the garden shed. Last winter, at -15 to -18°C (5 to 0°F), with the frost guard and several candles, the shed’s temperature stayed at about -7°C (19°F). Everything survived.
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