Hello everyone. I’m new here as of today.
Here’s the situation:
We want to build a bungalow this year, and it’s very important to me that there are no steps anywhere inside or around the house.
How deep can the foundation slab be set compared to the garden level?
A few details to help you picture it better:
My plot has about a 60 cm (24 inches) slope from the highest point down to the front door, and about 60 cm (24 inches) from the highest point to the terrace. The slope continues downward beyond that, so I will have to add a lot of soil around the terrace and entrance. That’s why I want to keep the foundation as low as possible.
Unfortunately, the builder says "you don’t put a foundation slab directly in the dirt," so he wants the top edge of the slab to be level with the lawn surface at the highest point in the garden.
What do you think about this?
It’s urgent, because the excavator will arrive on 16.01.2015.
Here’s the situation:
We want to build a bungalow this year, and it’s very important to me that there are no steps anywhere inside or around the house.
How deep can the foundation slab be set compared to the garden level?
A few details to help you picture it better:
My plot has about a 60 cm (24 inches) slope from the highest point down to the front door, and about 60 cm (24 inches) from the highest point to the terrace. The slope continues downward beyond that, so I will have to add a lot of soil around the terrace and entrance. That’s why I want to keep the foundation as low as possible.
Unfortunately, the builder says "you don’t put a foundation slab directly in the dirt," so he wants the top edge of the slab to be level with the lawn surface at the highest point in the garden.
What do you think about this?
It’s urgent, because the excavator will arrive on 16.01.2015.
First of all, thanks for so much participation, I’ll try to respond one by one:
@nathi
I spoke again with the architect and of course the building permit / planning permission states the height of the slab in relation to the ground level, but she says it can be adjusted on site as long as it does not change by about half a meter (20 inches).
Okay, “lawn level same as slab” means that first 25 cm (10 inches) of lawn soil is removed and then 25 cm (10 inches) of gravel is added back.
@bieber0815
I can’t upload a sketch, I don’t have a PC here, only a smartphone. It was already a hassle to register because the confirmation link in the email didn’t work, so I had to do it at a friend’s place.
No, no corner of the house is below ground level—in principle the patio door and entrance door are floating 60 cm (24 inches) above the ground, and I’ll have to add a lot of soil anyway. If the slab then comes 30 cm (12 inches) higher, I would need to fill almost a meter (3 feet) and I don’t want that.
Regarding 1.:
It’s not possible, if I handle it afterwards, the house could end up too high and I’d need to bring in massive amounts of soil.
Regarding 2.:
That’s a good idea, just cut down the highest spot on the plot a bit.
@eeepad
Saving money? On the contrary, I want to set the slab deeper, so more earthworks are needed.
Why no steps? Nobody here needs barrier-free access, but you never know what may come. Also, for convenience, I want to say I want to live “without obstacles.”
No basement below.
It’s important to me that it stays dry as well.
But from a different perspective, even if I wanted the top edge of the slab lower than the surrounding ground level, why shouldn’t it be possible? It just has to be waterproofed like a basement. For a basement that’s possible too.
Compared to the next street curb, the slab top is about 80 cm (31 inches) higher as I want it, and as the builder wants it 110 cm (43 inches) higher, so in both cases it’s no problem.
We’ll do the earthworks ourselves; my best friend is an excavator operator, he’ll do everything for a box of beer, and of course I’ll help him if he needs me.
@ypg
Exactly.
As I said, uploading is not possible.
Exactly.
@Bauexperte
Yes, the eaves height is specified, but my architect says that’s not a problem, there are certain tolerances, and it’s acceptable if it changes depending on a slight variation in slab height or if you adjust the garden. There’s also no issue with building a house and then lowering the entire garden by 50 cm (20 inches) a year later, even if that changes the eaves height. Just as an example.
Regarding rainwater, in my view there’s hardly a problem because our whole plot slopes away, so no water will pool against the house. The only critical spot is the highest point on the plot where I want the slab top edge to be the same level as the surrounding ground. I’d even accept the slab being 5 cm (2 inches) higher there to avoid problems. Also, in this area there are no doors or windows with very low sill heights, so there will be splash protection with decorative stones around the house, plus I have a lawn edging (how do you spell that?) that water will run along in case of heavy rain.
In the patio and entrance door area, as you suggested, I want a slope, basically wheelchair accessible. But the higher the slab, the steeper the slope, so I want the slab quite low.
@nathi
I spoke again with the architect and of course the building permit / planning permission states the height of the slab in relation to the ground level, but she says it can be adjusted on site as long as it does not change by about half a meter (20 inches).
Okay, “lawn level same as slab” means that first 25 cm (10 inches) of lawn soil is removed and then 25 cm (10 inches) of gravel is added back.
@bieber0815
I can’t upload a sketch, I don’t have a PC here, only a smartphone. It was already a hassle to register because the confirmation link in the email didn’t work, so I had to do it at a friend’s place.
No, no corner of the house is below ground level—in principle the patio door and entrance door are floating 60 cm (24 inches) above the ground, and I’ll have to add a lot of soil anyway. If the slab then comes 30 cm (12 inches) higher, I would need to fill almost a meter (3 feet) and I don’t want that.
Regarding 1.:
It’s not possible, if I handle it afterwards, the house could end up too high and I’d need to bring in massive amounts of soil.
Regarding 2.:
That’s a good idea, just cut down the highest spot on the plot a bit.
@eeepad
Saving money? On the contrary, I want to set the slab deeper, so more earthworks are needed.
Why no steps? Nobody here needs barrier-free access, but you never know what may come. Also, for convenience, I want to say I want to live “without obstacles.”
No basement below.
It’s important to me that it stays dry as well.
But from a different perspective, even if I wanted the top edge of the slab lower than the surrounding ground level, why shouldn’t it be possible? It just has to be waterproofed like a basement. For a basement that’s possible too.
Compared to the next street curb, the slab top is about 80 cm (31 inches) higher as I want it, and as the builder wants it 110 cm (43 inches) higher, so in both cases it’s no problem.
We’ll do the earthworks ourselves; my best friend is an excavator operator, he’ll do everything for a box of beer, and of course I’ll help him if he needs me.
@ypg
Exactly.
As I said, uploading is not possible.
Exactly.
@Bauexperte
Yes, the eaves height is specified, but my architect says that’s not a problem, there are certain tolerances, and it’s acceptable if it changes depending on a slight variation in slab height or if you adjust the garden. There’s also no issue with building a house and then lowering the entire garden by 50 cm (20 inches) a year later, even if that changes the eaves height. Just as an example.
Regarding rainwater, in my view there’s hardly a problem because our whole plot slopes away, so no water will pool against the house. The only critical spot is the highest point on the plot where I want the slab top edge to be the same level as the surrounding ground. I’d even accept the slab being 5 cm (2 inches) higher there to avoid problems. Also, in this area there are no doors or windows with very low sill heights, so there will be splash protection with decorative stones around the house, plus I have a lawn edging (how do you spell that?) that water will run along in case of heavy rain.
In the patio and entrance door area, as you suggested, I want a slope, basically wheelchair accessible. But the higher the slab, the steeper the slope, so I want the slab quite low.
B
Bauexperte10 Jan 2015 10:45Good morning,
Best regards, Bauexperte
knochi3 schrieb:I would be very surprised; in my area, the building authority allows zero tolerance when specified heights are exceeded. We had to lower by a full 2 cm (approximately 0.8 inches) on one of our recent construction projects, and that was in a § 34 zone! Don’t forget that in the end, the surveyor must come out again to carry out the final building survey.
Yes, eave height is specified, but my architect says that this is not a problem and that some tolerances are allowed.
knochi3 schrieb:Why would you reduce the thickness of your foundation slab to your own disadvantage? What does the structural engineer say about this proposal?
Besides, it’s okay if the height changes slightly due to a small adjustment of the slab thickness or if you modify the garden.
knochi3 schrieb:The required eave or ridge height has nothing to do with the ground level of your garden, does it?
There are also no problems if you build a house and a year later cut down the entire garden by 50 cm (20 inches), even if that changes the eave height. Just as an example.
Best regards, Bauexperte
Bauexperte schrieb:
Good morning,
I would be very surprised; in my area there is zero tolerance from the building authority when specified heights are exceeded. We had to reduce by a full 2cm (0.8 inches) on one of our latest construction projects, and that was in a zoning area under § 34! Don’t forget that in the end the surveyor must come back for the final survey of the ...
Regards, BauexperteHello, many homebuilders do not fully use the ridge height, eaves height, or overall height specified in the development plan. Then there are on-site options to decide whether the house can be built slightly higher on the plot. That was the case for us.
I’m not sure if this depends on the federal state?!
Of course, the height of the garden does not matter, only the building height.
B
Bauexperte10 Jan 2015 11:44Hello Yvonne,
Edit:
The height limits must be observed in every federal state; I can’t imagine it being different. Maybe it’s a question of mentality if the final foundation height is only determined at the last moment. It’s also a matter of budget.
Regards, Bauexperte
ypg schrieb:Ours don’t; sometimes it’s a matter of millimeters for our architects.
many builders do not fully utilize the ridge, eaves, or total height specified in the development plan.
ypg schrieb:No.
I don’t know if that depends on the region?!
Edit:
The height limits must be observed in every federal state; I can’t imagine it being different. Maybe it’s a question of mentality if the final foundation height is only determined at the last moment. It’s also a matter of budget.
Regards, Bauexperte
So, once again step by step:
@ Building Expert
I don’t want to exceed the specified heights; I want to stay below them.
I don’t want to reduce the thickness of the slab, but rather reduce the soil under the gravel beneath the slab. This won’t affect the structural integrity.
If the eaves height has nothing to do with the ground level, I don’t understand your original question... If I only reduce the dirt under the slab and the slab and entire house sit lower as a result, I’m not changing the eaves height.
@ypg, @Building Expert
In our case, there is still some leeway with the eaves height or total height because we actually prefer a roof pitch of 19 degrees (19°) for aesthetic reasons and planned accordingly, but the building permit/planning permission states 22 degrees (22°), resulting in a higher eaves height.
The structural engineer was, of course, informed and said he will design it so that it’s stable enough no matter which option we ultimately choose.
So, I’m pretty confident that legally, structurally, and regarding rainwater management, everything is fine.
What do you think? Should we push ahead against the construction company and insist on lowering the slab, or listen to the company and bring in tons of soil, making all the sloped areas in my garden unnecessarily steeper?
@ Building Expert
I don’t want to exceed the specified heights; I want to stay below them.
I don’t want to reduce the thickness of the slab, but rather reduce the soil under the gravel beneath the slab. This won’t affect the structural integrity.
If the eaves height has nothing to do with the ground level, I don’t understand your original question... If I only reduce the dirt under the slab and the slab and entire house sit lower as a result, I’m not changing the eaves height.
@ypg, @Building Expert
In our case, there is still some leeway with the eaves height or total height because we actually prefer a roof pitch of 19 degrees (19°) for aesthetic reasons and planned accordingly, but the building permit/planning permission states 22 degrees (22°), resulting in a higher eaves height.
The structural engineer was, of course, informed and said he will design it so that it’s stable enough no matter which option we ultimately choose.
So, I’m pretty confident that legally, structurally, and regarding rainwater management, everything is fine.
What do you think? Should we push ahead against the construction company and insist on lowering the slab, or listen to the company and bring in tons of soil, making all the sloped areas in my garden unnecessarily steeper?
The eaves height depends on a fixed point in the terrain, such as a manhole cover on the street or something similar, and not on your house itself.
I would recommend choosing a middle ground: you don’t need to build up a hill, but you should still ensure that water can flow away from the house within your property.
We also opted for the "lower" option. This caused other builders around us to be skeptical and look at our level with doubt, saying "You’re way too low." No, we’re not too low; we’re just lower than others. So far, we have not experienced any problems with rain.
I would recommend choosing a middle ground: you don’t need to build up a hill, but you should still ensure that water can flow away from the house within your property.
We also opted for the "lower" option. This caused other builders around us to be skeptical and look at our level with doubt, saying "You’re way too low." No, we’re not too low; we’re just lower than others. So far, we have not experienced any problems with rain.
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