Hello!
I am planning the excavation of our basement in our 1940s house.
Last summer we drained around the entire house and we had a constructor (an older gentleman who has been around for a while) there for another matter.
When I mentioned that we would excavate the basement and turn it into living space and that, to get proper ceiling height, we would have to dig out at least 40 cm, preferably 50 cm, and that it is about 20-25 cm below where the foundation wall ends.
He said that if you have drained + that you excavate as much as we are planning to do, there is a risk of settling in the house. I don't remember exactly why, but it had something to do with the ground becoming too dry due to the drainage.
His solution to this was to excavate 1-2 meters at a time along and even under the foundation wall. Then reinforce the foundation wall by casting again the excavated space under the foundation wall.
Opinions on this? Does anyone here know if it is necessary? I would prefer not to do this as it takes much longer than just excavating everything and putting on isodrän + cellplast and then casting (greatly simplified *S*).
I am planning the excavation of our basement in our 1940s house.
Last summer we drained around the entire house and we had a constructor (an older gentleman who has been around for a while) there for another matter.
When I mentioned that we would excavate the basement and turn it into living space and that, to get proper ceiling height, we would have to dig out at least 40 cm, preferably 50 cm, and that it is about 20-25 cm below where the foundation wall ends.
He said that if you have drained + that you excavate as much as we are planning to do, there is a risk of settling in the house. I don't remember exactly why, but it had something to do with the ground becoming too dry due to the drainage.
His solution to this was to excavate 1-2 meters at a time along and even under the foundation wall. Then reinforce the foundation wall by casting again the excavated space under the foundation wall.
Opinions on this? Does anyone here know if it is necessary? I would prefer not to do this as it takes much longer than just excavating everything and putting on isodrän + cellplast and then casting (greatly simplified *S*).
What is your ceiling height today and what do you consider "proper"?
If you need to excavate as much as 40-50cm, you'll probably need to pour a new foundation wall, but if you manage with maybe 25 cm and not all the way to the foundation wall, it should be fine.
If you need to excavate as much as 40-50cm, you'll probably need to pour a new foundation wall, but if you manage with maybe 25 cm and not all the way to the foundation wall, it should be fine.
Well, I didn't dare to dig deeper than the bottom edge of the foundation sill. But since my basement isn't primarily a living space, it's fine for me to continue living with a ceiling height of 2.10 m, but now with underfloor heating and insulation under the slab.
Today it varies between 190-195 depending on where you are in the basement. Ideally, I want to reach 210 cm, maybe a bit more. I have many TAAAALL relativessnuttjulle said:
When calculating backwards, I must go down as much as 40-50cm: 20cm insulation, you might scrimp and go with 15 or even 10cm if necessary, but from what I have read here on the forum, that is not recommended. 10cm concrete (with underfloor heating) 2cm (tiles) floor.
I have actually considered not digging out completely next to the wall (about 20 cm in from the wall) and simply skipping insulation there. Then, I'll lay the insulation over the rest of the ground so it comes level with the ground next to the outer wall. Is this a feasible path?
One more thing that came to mind: How do I deal with the sewer pipes?
I can't place them 50cm lower than they are today because then they would be below the connection outside the house.
Can they be run in the insulation?
I can't place them 50cm lower than they are today because then they would be below the connection outside the house.
Can they be run in the insulation?
It is fine to run the drainage through the insulation, that's how it's usually done!
And regarding how deep you have to dig, if you have trouble reaching a sufficient depth, 10cm of cellplast is adequate under a basement floor!
And regarding how deep you have to dig, if you have trouble reaching a sufficient depth, 10cm of cellplast is adequate under a basement floor!
Ok thanks! I looked a bit at MattiasS' basement project and it seemed like he dug them into the ground.injonil said:
Isn't it better with just 10 cm of Isodrän as insulation instead of the cell plastic? That way, you avoid having to haul in a lot of macadam
Well, maybe, but you don't need much macadam, just a few cm to act as a capillary break and to level the ground so it's flat. Then the cell plastic is partially capillary-breaking as well. Cheaper and not worse in any way, I would say!
Found a link to someone who has done exactly what I was planning to do
http://www.byggahus.se/forum/grund-markarbeten/91746-graeva-ur-kaellare.html
http://www.byggahus.se/forum/grund-markarbeten/91746-graeva-ur-kaellare.html