ᐅ House extends above ground level – how much soil can be backfilled (with shallow basement)?

Created on: 15 Oct 2022 19:11
M
Machu Picchu
Hello everyone,

we are now in the final phase of our house construction.

Because the sewage system on our property is not far below ground level and we did not install a sewage lift system, our basement was only excavated to a shallow depth.

The ceiling height of the basement rooms is 2.50m (8 feet 2 inches), as these areas are intended to be living spaces, unlike the neighboring houses, whose basement heights are lower.

As a result, our front door and the two patio doors are positioned much higher than those of the neighboring houses. In the next few days, soil will be filled up to the level of the terrace and front doors.

I do not want this to turn into a discussion about different construction methods; instead, I am looking for advice on how to best handle this somewhat unusual situation.

First, some photos:



Marked in red are the two patio doors. Soil will be filled up to just below these patio doors, except, of course, at light wells and shafts. The terrace will be paved around the corner, following the two indicated patio doors (because we wanted two sunny sides on the terrace for different times of the day). To the left of the single-leaf patio door (where the exterior plaster ends), a retaining wall will be built from the terrace level down to the ground.



This is a front view. On the left, the construction staircase leads up to the entrance door. The front door is at the same level as the two patio doors.



Here is the view from the back.



This is the view from the back toward the front door.



And here is another rear view including the neighboring houses.

As planned, as mentioned, soil will be filled up to the level of the house and terrace doors, and at this level the garden will be designed on the side of the large double patio door as well as behind the house, with steep slopes created just before the property boundary.

On the front door side, soil will also be filled up to front door level.

Toward the "front" (the side with the single patio door), the street level will be reached by terrace-like steps with 2-3 slope terraces supported by walls/granite.

Our concern now is: if we fill soil all around the house at door level on the side with the double patio door, at the back, and on the front door side, our garden height will be so high that, compared to the neighbors, our house will stand out significantly due to the very elevated ground level.

We are now considering ways to soften this.

One idea is to fill soil to door level only at the terrace wrapping the corner and directly at the front door, and to fill soil, for example, 50cm (20 inches) below door level everywhere else.

This way, the garden level would not be so dramatically higher than the neighbors’.

The problem with this is that we would partially expose the "basement" and areas without exterior plaster would become visible. We would likely need to hire a plasterer on our own to plaster additional areas and paint them with gray base paint. Time is tight because the soil will be delivered for filling within the next days/weeks. How long would such plastering take and what would it approximately cost?

Question to the forum: What do you think about this? Do you have other solutions? Or are our concerns unfounded?

Thank you very much in advance for any advice.
H
hanse987
15 Oct 2022 23:14
Machu Picchu schrieb:

Question to the forum: What do you think about this? Do you have alternative solutions? Or are our concerns unfounded?

My advice is to consult a skilled and experienced landscape gardener! They might be able to salvage and improve something. However, in my opinion, it won’t be cheap.

What kind of living space is actually in the basement? Because I only see two proper windows there.
M
Machu Picchu
15 Oct 2022 23:17
Myrna_Loy schrieb:

And plan the stairs to the terrace as seating steps and possibly with planter boxes. I would never build up to the full planned height! That’s too much effort for a garden that ends up absolutely unattractive and rightly annoying neighbors who have to look at retaining walls.

If we now rule out building up to the full height, there are probably three options:

1) The entire plot remains at street level. The front door is reached by steep stairs. Only the terrace area is built up.
Disadvantages: The foundation color was pointless, small light well windows in the basement or ground floor were unnecessary, and much exterior plaster is missing.
Question: How could the terrace be connected to the garden, which lies 2 meters (6.5 feet) lower, in this scenario?

2) Like option 1, but instead of a built-up terrace, there is a terrace balcony.
Disadvantage: It is almost impossible to walk between the balcony and garden level (less than 2 meters (6.5 feet) height).
Question: Would it be feasible for the balcony to be so large that it wraps around the corner and includes the single-leaf terrace door? If not, does the single-leaf terrace door pose a safety risk (if opened, there would be an unsecured 2-meter (6.5 feet) drop)?

3) The ground is only built up by one meter (3 feet). I doubt there would still be space for (seating) stairs between the terrace and the garden area 1 meter (3 feet) lower. There is a total of 8 meters (26 feet) of space from the terrace door to the neighboring property. The terrace is 3 meters (10 feet) wide, 2 meters (6.5 feet) wide for such seating stairs with a step, leaving only 2 meters (6.5 feet) for a green strip and 1 meter (3 feet) for sloping toward the property boundary – everything feels very tight, but could it work out this way?
For this option, I would also need to have the unplastered exterior areas plastered – how long does that usually take?
K
kbt09
15 Oct 2022 23:19
Machu Picchu schrieb:

Only one meter (3.3 feet) of fill will be added.
And then, a staircase leading out from the terrace door? Or how do you imagine it?
M
Machu Picchu
15 Oct 2022 23:30
askforafriend schrieb:

So, you didn’t visit the site even once?

Yes, we visited the site several times, also together with the general contractor.
He was the first GC who immediately inspected the site and was the only one who noticed that the sewer line is not far underground, so we needed to have the basement raised. Back then, we were relieved because all the other GCs we consulted planned a regular basement that would have been built at a normal depth underground, which would have failed in our case due to the sewer line.
askforafriend schrieb:

What kind of GC is that? Is this his first house project?

He has been around for decades...
askforafriend schrieb:

You considered raising the basement and building retaining walls to be cheaper than installing a pump system?

Raising the basement actually saved costs compared to the originally desired standard-depth basement (which was not feasible).
And yes, a retaining wall was required on the left side of the single-leaf terrace door. Otherwise, no expensive mandatory walls or similar structures were proposed at the time; rather, the idea was to slope the ground towards the neighbor without building walls.
askforafriend schrieb:

Honestly, no one here can help.

On the contrary, some of the advice has already been helpful.
M
Machu Picchu
15 Oct 2022 23:31
kbt09 schrieb:

And then a staircase coming out of the patio door? Or how do you imagine it?

The terrace will, of course, be at the same level as the patio door. From the terrace, there will then be a step or staircase down to the ground, approximately 1 meter (3.3 feet).
M
Machu Picchu
15 Oct 2022 23:33
hanse987 schrieb:


What kind of living space is actually planned in the basement? Because I only see two real windows there.

A study and a guest room are planned there.