2,919 views ·
15 replies
3k views
15 replies
Basement construction
Page 1 of 2
I have bought a plot where I plan to blast a two-story basement.
This raises a couple of questions.
When you have rock around the house, why should you then backfill against the basement foundation? I thought it would be better from a drainage perspective not to do it and instead have air between the rock and the basement wall. What do you think?
What materials could be used in a basement wall if done in that way?
Are there any who have done this, I can't find that type of solutions, but still think it should be a logical solution when you have blasted down and have rock all around.
This raises a couple of questions.
When you have rock around the house, why should you then backfill against the basement foundation? I thought it would be better from a drainage perspective not to do it and instead have air between the rock and the basement wall. What do you think?
What materials could be used in a basement wall if done in that way?
Are there any who have done this, I can't find that type of solutions, but still think it should be a logical solution when you have blasted down and have rock all around.
The idea is to blast a shaft where you can drive the car into the basement, so no pool... Sewage, drainage, etc., will be solved via that shaft.J jojo123 said:
The problem would have remained even if I had refilled around the walls, so regardless, that problem needs to be addressed...
On larger construction sites that are blasted into a mountainside, there is a gap to the rock, perhaps 2 - 3 meters, with coarse crushed stone and macadam as a floor. Rock water then runs down along the rock and is drained away. This means that no moisture or dampness reaches the foundation, but there should be ventilation there, natural ventilation works fine.
In your case, I would have about 1 meter between the rock and the foundation and the possibility of going in to inspect. What can be a bit tricky is that there must be a cast roof sloping away from the foundation, with a sikacoated rock at the connection to the mountain.
It is also possible to let the roof extend out and up towards the rock so that it forms a gutter for all stormwater to run into pipes that go down to the drainage, a bit like internal downspouts, so it doesn't freeze.
In your case, I would have about 1 meter between the rock and the foundation and the possibility of going in to inspect. What can be a bit tricky is that there must be a cast roof sloping away from the foundation, with a sikacoated rock at the connection to the mountain.
It is also possible to let the roof extend out and up towards the rock so that it forms a gutter for all stormwater to run into pipes that go down to the drainage, a bit like internal downspouts, so it doesn't freeze.
Interesting...J jojo123 said:On larger construction sites that are blasted into a mountainside, there is a gap to the rock, it is perhaps 2-3 meters to the rock and coarse crushed stone plus macadam as a floor, mountain acid then runs down along the rock and is drained away. This means that no moisture reaches the foundation, but there should be ventilation there, natural ventilation works well. In your case, I would have about 1 meter between the rock and the foundation and the ability to go in and inspect. What can be a bit tricky is that there must be a cast roof that slopes out from the foundation, with Sikasealed rock at the connection to the rock. It is also possible to let the roof extend out and up against the rock so it acts like a gutter. All rainwater can run into pipes that lead down to the drainage, a bit like internal downspouts, then it won't freeze.
Regarding the "roof" over the gap, I had thought of building it with a slope, I think that would be the simplest way to achieve it, at least on the side where the plot slopes towards the house.
How damp can one expect the gap between the rock and the house to be? What requirements does such a solution place on the basement wall?
Now, when it comes to larger buildings, we're talking about large volumes, it might be 5-6 meters in ceiling height and perhaps 30 meters around, and with today's situation with VP, it is ventilated with recycling and then there's nothing, just the concrete. I've had my thoughts on this, but haven't built anything or thought of blasting into a house; what has emerged is that the old method of tar on the outside is sufficient when talking to people, and insulation shouldn't be needed either, it becomes a warm zone in the cavity.
Ventilation: it entirely depends on how much water comes in through the rock, but consider how it's done when new drainage is done on a house: a Platon or something else against the foundation, just a mat and fill of various materials performs it. Then a couple of 110 mm pipes with a gooseneck in a few places are enough, it might be good to run a pipe for electricity to a small fan if needed. There are fans that fit directly in, 110 pipes, have you checked that there isn't radon in the rock? Then you'd need to arrange the ventilation in a slightly different way, but it's possible to get it sorted.
Ventilation: it entirely depends on how much water comes in through the rock, but consider how it's done when new drainage is done on a house: a Platon or something else against the foundation, just a mat and fill of various materials performs it. Then a couple of 110 mm pipes with a gooseneck in a few places are enough, it might be good to run a pipe for electricity to a small fan if needed. There are fans that fit directly in, 110 pipes, have you checked that there isn't radon in the rock? Then you'd need to arrange the ventilation in a slightly different way, but it's possible to get it sorted.
The thought can't be stopped. Thinking about one thing, what happens if you hit a cold spring vein during blasting, a lot of water can come from such a source and it has to be removed, is there a possibility for that, nowadays every property has to take care of its own drainage water.
It is located on a height so I find it hard to believe there is any water in the rock there...J jojo123 said:
Not cause problems to the extent that might be feared, but there's always water in rocks and if you blast, it can open up or create cracks that let some water in continuously, not much but constant, not good against a basement wall or floor.O Exsicco said:
It can naturally be drained away, then there should be a lot of crushed stone under the slab and a gap between the wall and the rock, if there's water it must be able to drain away under the slab, it can be done.
I don't want to paint the devil on the wall, but I've seen such things before and it's better to be proactive rather than reactive in thoughts.
I meant the plant bergsyra...J jojo123 said:Not to cause problems to the extent that can be feared, but there is always water in rock and when blasting it can open up or create cracks that let some water through all the time, not much but constant, not good against basement wall or floor. It can naturally be drained away, but then there needs to be a lot of crushed stone under the slab and some space between the wall and the rock, if there is water it must be able to run off under the slab, this can be achieved. I don't want to paint the man on the wall, but I have seen this before and it's better to be proactive in your thoughts.