Hello!
I'm considering and planning a somewhat larger project under the house.
(There are several reasons for this. One reason is drainage.)
There is currently no basement under the entire house, and the part lacking a basement will now get one.
Initially, I thought of supporting the house with a long steel beam to create an open space where the basement wall will stand.
This would mean the house would only need to be supported at a few points and have relatively open access for digging out the soil.
But right now, it seems that the house (probably a frame house mainly from the early 1900s) can only be lifted under the old stone foundation, which in turn stands on boulders.
Hence my question.
This would mean I have to place props (perhaps 4 on 9m?) right where the wall is supposed to be.
But the props are directly in the way, initially where I'd like to cast the foundation wall.
(I might have to weld "bridges" for the props to stand on to be able to cast the foundation wall - but then the props might become too long.
Can the props be built out of wood? (how to dimension them?)
This can probably be solved somehow, but then there's the wall.
Can/should new "pillars" be built or cast for the house to start resting on?
Then cast or lay bricks for the rest?
How do you proceed - step by step - to achieve the best possible result?
//Jan
I'm considering and planning a somewhat larger project under the house.
(There are several reasons for this. One reason is drainage.)
There is currently no basement under the entire house, and the part lacking a basement will now get one.
Initially, I thought of supporting the house with a long steel beam to create an open space where the basement wall will stand.
This would mean the house would only need to be supported at a few points and have relatively open access for digging out the soil.
But right now, it seems that the house (probably a frame house mainly from the early 1900s) can only be lifted under the old stone foundation, which in turn stands on boulders.
Hence my question.
This would mean I have to place props (perhaps 4 on 9m?) right where the wall is supposed to be.
But the props are directly in the way, initially where I'd like to cast the foundation wall.
(I might have to weld "bridges" for the props to stand on to be able to cast the foundation wall - but then the props might become too long.
Can the props be built out of wood? (how to dimension them?)
This can probably be solved somehow, but then there's the wall.
Can/should new "pillars" be built or cast for the house to start resting on?
Then cast or lay bricks for the rest?
How do you proceed - step by step - to achieve the best possible result?
//Jan
Place the post a bit into the room (about 80 cm in, make sure you hit load-bearing material in both the ceiling and floor). On top of the post, place a glued laminated timber or double 45x220 that is pressed against the ceiling. Rent an actual post so you can over-tension them, about 7 mm. Then you can demolish and excavate under the upcoming wall. Once your new wall is ready, release the post, and the joists will land on your new wall.
Thank you!
(sorry for my ignorance on this.)
First, I planned to insert an "H-beam" under the entire house (11m), filling in so that the house would lift on all beams.
Put 3 supports there to hold it up.
At both ends passing through the side walls - no problem, but the long side - completely without support...
The challenge is getting the beam under that might weigh 1000-1500kg? - and a bit of hassle to dig down the supports and lift.
The clearance, currently under the house, is maybe 0.4m.
When I look under the house, I see the floor joists running across - about 50-70cm between them (I haven't measured).
Between these beams, some form of "ceiling" has been nailed to hold up the sawdust, which is the existing insulation.
If I push these beams up, the "floor" will be lifted, but do the outer walls really stand on these beams?
That is, how are the ends of these beams fastened in the wall of an old house? (I can't see anything because of the "underside" holding up the sawdust)
I don't see any "massive beams" that can be found in a log house. on which the walls stand.
Will the ends of the floor beams be able to lift the wall?
Or will the wall want to press outwards?
(felt exciting)
It's in the outer wall where the weight of the house lies.
Suppose I start lifting the floor beams about 80cm from the outer wall of the house.
Towards the outer wall, it's clear, but in the other direction, there is an existing basement, complete with chimney - that side will not be able to be "moved."
At least one board/plank or ?? will remain on the existing foundation (cast with natural stone as reinforcement) - or will the entire wall remain and only the floor be pushed up?
Isn't the floor only built to resist pressure from above - not from below?
//Jan
(sorry for my ignorance on this.)
First, I planned to insert an "H-beam" under the entire house (11m), filling in so that the house would lift on all beams.
Put 3 supports there to hold it up.
At both ends passing through the side walls - no problem, but the long side - completely without support...
The challenge is getting the beam under that might weigh 1000-1500kg? - and a bit of hassle to dig down the supports and lift.
The clearance, currently under the house, is maybe 0.4m.
When I look under the house, I see the floor joists running across - about 50-70cm between them (I haven't measured).
Between these beams, some form of "ceiling" has been nailed to hold up the sawdust, which is the existing insulation.
If I push these beams up, the "floor" will be lifted, but do the outer walls really stand on these beams?
That is, how are the ends of these beams fastened in the wall of an old house? (I can't see anything because of the "underside" holding up the sawdust)
I don't see any "massive beams" that can be found in a log house. on which the walls stand.
Will the ends of the floor beams be able to lift the wall?
Or will the wall want to press outwards?
(felt exciting)
It's in the outer wall where the weight of the house lies.
Suppose I start lifting the floor beams about 80cm from the outer wall of the house.
Towards the outer wall, it's clear, but in the other direction, there is an existing basement, complete with chimney - that side will not be able to be "moved."
At least one board/plank or ?? will remain on the existing foundation (cast with natural stone as reinforcement) - or will the entire wall remain and only the floor be pushed up?
Isn't the floor only built to resist pressure from above - not from below?
//Jan
The base is of moraine or sand-like (fine-grained sand) - not stone or clay. Each post should be placed on a plank, to reduce ground pressure.
My estimate is that the part of the house that needs to be supported cannot weigh more than 8-10 tons. Does that sound reasonable?
This would result in about 2-2.5 tons per post. (4 in total)
With a plank of 0.5m (2" x 4), the ground pressure would be 4-5kg/cm2
(Which I don't think sounds like much. Am I wrong?)
//Jan
My estimate is that the part of the house that needs to be supported cannot weigh more than 8-10 tons. Does that sound reasonable?
This would result in about 2-2.5 tons per post. (4 in total)
With a plank of 0.5m (2" x 4), the ground pressure would be 4-5kg/cm2
(Which I don't think sounds like much. Am I wrong?)
//Jan
The project has progressed, and I have started digging under the house.
The sill was sturdy - (maybe 25x25cm) and was perfect to lift underneath.
Perhaps my main question is:
- What alternatives are there to build on?
- Method? / Material?
To make an assessment myself on which method feels easiest.
______________________________________
They had not placed tar paper on top of the stone foundation, so the sill has started to soften / "rot" in some places...
The sill is not so damaged that it needs to be replaced - but I don't want the process to continue.
How should one stop the rotting process?
The only way I managed to support the house was to place logs under the sill about 2m apart.
I placed the logs on double "garden slabs" and it seems to hold.
Currently, the clearance is about 2.6m and the excavation of the soil masses continues.
__________________________
My first thought was to:
- Dig
- Fill the surface with gravel (15-20cm)
- Cast a footing. (30x40 cm?)
- On that, build/cast a wall. (Material?)
- Insulation - wall
- Insulation in the floor (thickness 15cm?)
- Cast a floor with underfloor heating loops.
- possibly some floor covering / or paint.
Right now, my "log pillars" are exactly where the footing would be cast...
I started googling around and see that it is not always built that way now.
Some place insulation directly on the ground (without gravel underneath)
and the wall is placed on the floor - not the floor between the walls...
Is it possible to choose some insulation block to build the wall from?
like Jackon - https://www.jackon.se/produkter-bygg/jackon-thermomur/thermomur-350/
The biggest problem arises "at the top" - How to cast, yet not....
idea? / tips?
Other options?
Is it better to build "trestles" to provide "free space" for the footing?
or should one build the floor around the logs and place the wall on the floor?
Cut away the logs and fix the floor where the logs stood.
//Jan
The sill was sturdy - (maybe 25x25cm) and was perfect to lift underneath.
Perhaps my main question is:
- What alternatives are there to build on?
- Method? / Material?
To make an assessment myself on which method feels easiest.
______________________________________
They had not placed tar paper on top of the stone foundation, so the sill has started to soften / "rot" in some places...
The sill is not so damaged that it needs to be replaced - but I don't want the process to continue.
How should one stop the rotting process?
The only way I managed to support the house was to place logs under the sill about 2m apart.
I placed the logs on double "garden slabs" and it seems to hold.
Currently, the clearance is about 2.6m and the excavation of the soil masses continues.
__________________________
My first thought was to:
- Dig
- Fill the surface with gravel (15-20cm)
- Cast a footing. (30x40 cm?)
- On that, build/cast a wall. (Material?)
- Insulation - wall
- Insulation in the floor (thickness 15cm?)
- Cast a floor with underfloor heating loops.
- possibly some floor covering / or paint.
Right now, my "log pillars" are exactly where the footing would be cast...
I started googling around and see that it is not always built that way now.
Some place insulation directly on the ground (without gravel underneath)
and the wall is placed on the floor - not the floor between the walls...
Is it possible to choose some insulation block to build the wall from?
like Jackon - https://www.jackon.se/produkter-bygg/jackon-thermomur/thermomur-350/
The biggest problem arises "at the top" - How to cast, yet not....
idea? / tips?
Other options?
Is it better to build "trestles" to provide "free space" for the footing?
or should one build the floor around the logs and place the wall on the floor?
Cut away the logs and fix the floor where the logs stood.
//Jan