I am sitting and pondering a potential future project. I live on a gravel ridge, and I have a spot that for various reasons would be suitable for creating an underground garage. It won't just be a garage, but also a utility room (heat pump, pressure tank, etc.). The dimensions would be about 7 meters deep and 8 meters wide. The garage would be completely below ground level, except for the doors which would be on one side, along with the surrounding wall on the same side, with the remaining walls and roof below ground level.
The construction would look like this: first, a cast slab with insulation underneath, a wall about 3 meters high made of leca, with insulation on the outside. Then a cast roof on top, some form of insulation. On top of that, there will be a layer of patio gravel, and a "patio" of gravel where one can walk, and perhaps occasionally drive a car.
Now to the tricky part:
1: What does the cast roof look like? Can I build a form, reinforce, and cast it? What does the construction roughly look like? I assume I can buy prefab roof sections and place them on top; what might these cost approximately, much more expensive than casting myself?
2: How do I achieve the insulation, what might be practical? It should have gravel on top, which should be walkable and drivable.
3: How do I make the roof watertight? Even though it is to be a garage, I want it to be as close to a livable climate inside as possible. I suspect it will also be used for storage of more sensitive items, like furniture, from time to time.
So what do you think, feasible or should the ideas remain a dream?
The construction would look like this: first, a cast slab with insulation underneath, a wall about 3 meters high made of leca, with insulation on the outside. Then a cast roof on top, some form of insulation. On top of that, there will be a layer of patio gravel, and a "patio" of gravel where one can walk, and perhaps occasionally drive a car.
Now to the tricky part:
1: What does the cast roof look like? Can I build a form, reinforce, and cast it? What does the construction roughly look like? I assume I can buy prefab roof sections and place them on top; what might these cost approximately, much more expensive than casting myself?
2: How do I achieve the insulation, what might be practical? It should have gravel on top, which should be walkable and drivable.
3: How do I make the roof watertight? Even though it is to be a garage, I want it to be as close to a livable climate inside as possible. I suspect it will also be used for storage of more sensitive items, like furniture, from time to time.
So what do you think, feasible or should the ideas remain a dream?
Member
· Norrbotten
· 3 390 posts
Everything is possible, but perhaps not cheap or easy.
Having a cast vault with an 8 m span will require some effort with your concrete, perhaps pre-stressed beams? The weight of this may not be safely supported on a simple leca wall without possibly needing correctly dimensioned concrete for the exterior walls as well, including the foundation. These load calculations should be discussed with an engineer.
Waterproof from above? Your construction will be similar to many flat gravel-filled roofs. You should have a slope, or alternatively a curved span, so that water drains off. On top of this, a classic asphalt-based roofing. It lasts quite a long time but not forever, and you must be able to re-lay it in 20-30 years or so.
External insulation, like Isodrän and/or substantial drainage around the construction to maintain a dry climate inside.
Having a cast vault with an 8 m span will require some effort with your concrete, perhaps pre-stressed beams? The weight of this may not be safely supported on a simple leca wall without possibly needing correctly dimensioned concrete for the exterior walls as well, including the foundation. These load calculations should be discussed with an engineer.
Waterproof from above? Your construction will be similar to many flat gravel-filled roofs. You should have a slope, or alternatively a curved span, so that water drains off. On top of this, a classic asphalt-based roofing. It lasts quite a long time but not forever, and you must be able to re-lay it in 20-30 years or so.
External insulation, like Isodrän and/or substantial drainage around the construction to maintain a dry climate inside.
Sure, a designer probably gets contacted before the project starts, but now it's mostly at the stage of whether it can be completed with a reasonable budget or not.
What are pre-stressed beams, how do they work, and what do they cost? How should the walls be designed to support the roof if a lecavägg is too weak?
I was thinking of a sloped roof, and replacing it after 30 years is no problem. Maybe one can order a rubber membrane, the kind used for ponds and lay it on; it should be durable and waterproof.
What are pre-stressed beams, how do they work, and what do they cost? How should the walls be designed to support the roof if a lecavägg is too weak?
I was thinking of a sloped roof, and replacing it after 30 years is no problem. Maybe one can order a rubber membrane, the kind used for ponds and lay it on; it should be durable and waterproof.
Cool concept, but have they made the garages in gold? Not much you get for the price. However, it's convenient to just buy and place. Though the shipping was insanely expensive.
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