ᐅ Single-Family Home Construction Plan: Key Issue – Basement Living Space, Dream or Nightmare
Created on: 13 Oct 2015 16:19
M
MarcWen
Dear forum members, we need some support. To possibly take some concerns off our minds or to gather more courage. For about four weeks now, we have been going in circles without making real progress.
Without going into too much detail, it should be possible to provide a realistic assessment of whether our project is feasible:
We are leaving out landscaping and so on. Otherwise, no major frills or anything like that planned. Room and floor layouts are practical and functional. For example, there is only one bathroom per floor (~10 sqm (110 sq ft), so no wellness area or cost drivers). The house type also does not include many extras at this stage—no bay windows, balconies, many windows, etc., just a simple gable roof on top.
Of course, I could now calculate the 210 sqm (2,260 sq ft) of living space at the commonly quoted rate of 2,000 euros per sqm + garage + basement.
The sticking point is always this living basement. Everyone seems to struggle with it, or we haven’t found the right builder yet. At the beginning, we looked at some online sources and roughly budgeted around 60,000 euros. However, the feedback from our current contacts is mostly just a dismissive smile. Some of the estimates even made me hold back laughter:
Surely, the truth lies somewhere in between, but what would be realistic? Unfortunately, conversations usually fail at this point, with the question of what else to consider or revise. Then the house ends up costing 600,000+ euros, and I have the uneasy feeling that we are planning our living basement more as a goldmine for the builder.
Without going into too much detail, it should be possible to provide a realistic assessment of whether our project is feasible:
- Plan for a one-and-a-half-story single-family house, footprint approximately 10 x 12 meters (knee wall about 1 meter)
- KFW 55 standard
- If I roughly calculate, the ground floor and upper floor together add up to about 210 sqm (2,260 sq ft) of living space
- Move-in ready construction
- Now I take this hypothetical single-family house and instead of building on a concrete slab, plan a basement with about 75 sqm (810 sq ft) of living space (rest as usable space)
- We complete our dream with a double garage including a walkable roof terrace
We are leaving out landscaping and so on. Otherwise, no major frills or anything like that planned. Room and floor layouts are practical and functional. For example, there is only one bathroom per floor (~10 sqm (110 sq ft), so no wellness area or cost drivers). The house type also does not include many extras at this stage—no bay windows, balconies, many windows, etc., just a simple gable roof on top.
Of course, I could now calculate the 210 sqm (2,260 sq ft) of living space at the commonly quoted rate of 2,000 euros per sqm + garage + basement.
The sticking point is always this living basement. Everyone seems to struggle with it, or we haven’t found the right builder yet. At the beginning, we looked at some online sources and roughly budgeted around 60,000 euros. However, the feedback from our current contacts is mostly just a dismissive smile. Some of the estimates even made me hold back laughter:
- Sometimes costs are double-counted; the living basement costs a total sum x, plus cost per sqm of living space
- The ground floor is projected downward: 120 sqm (1,290 sq ft) x 2,000 euros per sqm, totaling 200,000 euros
- The living basement is almost like a separate house or bungalow, so it costs about 250,000 euros
Surely, the truth lies somewhere in between, but what would be realistic? Unfortunately, conversations usually fail at this point, with the question of what else to consider or revise. Then the house ends up costing 600,000+ euros, and I have the uneasy feeling that we are planning our living basement more as a goldmine for the builder.
B
Bieber081514 Oct 2015 22:07MarcWen schrieb:
I think for us the decision has been made to build with an architect. In my opinion, anything that is not really "standard" (meaning only roughly available in a builder’s catalog) should be built with an architect. So... good luck with your plot search!
The correct approach is indeed to first consider the size of the house (gross floor area / gross volume), the number of floors, the number of separate residential units, etc., and then look for a suitable plot of land, which may not be easy in the Cologne metropolitan area. Perhaps you could explore the Zülpich region.
The house design is then developed by the architect based on this basic concept, within the framework of the building and planning regulations applicable to the desired plot, which are often specified in a zoning plan: site coverage ratio / floor area ratio (land use), eave and ridge heights, roof shape, building lines, building boundaries, etc.
If no zoning plan exists, the approval of the building project must be negotiated and coordinated with the relevant building authorities through a preliminary building inquiry according to §34 of the Building Code. The effort required for building a basement is determined by geological and hydrological conditions, assessed in a soil survey, which may not be available before purchase but can possibly be reviewed for an existing building project in the neighborhood. In principle, living spaces should be built above ground level; basements are essentially elaborate storage or technical rooms that can often be constructed more cost-effectively elsewhere if site conditions allow.
The mentioned budget is realistic but will be decisively influenced by the house design (concept, construction, building services) and your equipment preferences. Here too, the architect can adjust many "parameters" to achieve an optimal result within a defined budget.
The house design is then developed by the architect based on this basic concept, within the framework of the building and planning regulations applicable to the desired plot, which are often specified in a zoning plan: site coverage ratio / floor area ratio (land use), eave and ridge heights, roof shape, building lines, building boundaries, etc.
If no zoning plan exists, the approval of the building project must be negotiated and coordinated with the relevant building authorities through a preliminary building inquiry according to §34 of the Building Code. The effort required for building a basement is determined by geological and hydrological conditions, assessed in a soil survey, which may not be available before purchase but can possibly be reviewed for an existing building project in the neighborhood. In principle, living spaces should be built above ground level; basements are essentially elaborate storage or technical rooms that can often be constructed more cost-effectively elsewhere if site conditions allow.
The mentioned budget is realistic but will be decisively influenced by the house design (concept, construction, building services) and your equipment preferences. Here too, the architect can adjust many "parameters" to achieve an optimal result within a defined budget.
S
Sebastian7915 Oct 2015 07:35[TE="merlin83, post: 103986, member: 21971"]Okay – and how do you justify that? It’s not that I don’t want to believe you, but it would be easier to understand with an explanation.[/QUOTE]
It’s simple: you only have one offer – which is an estimate – and during the construction phase, decisions can quickly cause costs to rise (usually the homeowner is responsible for any increase, as it reflects their wishes).
In my experience, the structural shell contractor is the most cost-effective trade regarding price/performance – costly surprises are more likely with roofing, electrical, heating/plumbing...
Earthworks aren’t without their challenges, either...
Well, maybe you’ll be lucky – but I wouldn’t rely on that until you receive the final invoice.
It’s simple: you only have one offer – which is an estimate – and during the construction phase, decisions can quickly cause costs to rise (usually the homeowner is responsible for any increase, as it reflects their wishes).
In my experience, the structural shell contractor is the most cost-effective trade regarding price/performance – costly surprises are more likely with roofing, electrical, heating/plumbing...
Earthworks aren’t without their challenges, either...
Well, maybe you’ll be lucky – but I wouldn’t rely on that until you receive the final invoice.
B
Bauexperte15 Oct 2015 11:53Good morning,
Setting basic parameters like the number of stories and possibly the roof shape is one thing; developing a house design for which there is no 100% certainty that it can actually be built is quite another.
I know many architects, but only a few who are actually able to have their own cost estimates confirmed by the final construction. Happy clients who can name such a professional as their contractor
Regards, Bauexperte
W. Pickartz schrieb:So far, I agree; although who would want to move to Zülpich...?
The correct procedure is indeed to first consider the size of the house (gross floor area/gross volume), the number of floors, the number of separate residential units, etc., and then look for a suitable plot of land, which is probably not easy in the Cologne metropolitan area. Maybe you could take a look around the Zülpich area.
W. Pickartz schrieb:Here we differ, as I see no point in raising expectations that I cannot be certain I will ultimately be able to realize.
The house design is then developed by the architect based on this basic concept within the framework of the building and planning regulations applicable to the desired plot, which are, for example, set out in a zoning plan: floor area ratio/building volume ratio (land use efficiency); eaves and ridge heights, roof shape, building lines, building boundaries, etc.
Setting basic parameters like the number of stories and possibly the roof shape is one thing; developing a house design for which there is no 100% certainty that it can actually be built is quite another.
W. Pickartz schrieb:Yes, I know those levers... “choose exterior insulation and finish system, install a gas condensing boiler, etc...”
The mentioned budget is realistic but is decisively defined by the house design (concept, construction, building services) and your desired features. The architect can also adjust many “levers” here to achieve an optimal result within a defined budget.
I know many architects, but only a few who are actually able to have their own cost estimates confirmed by the final construction. Happy clients who can name such a professional as their contractor
Regards, Bauexperte
Bauexperte schrieb:
Yes, I’m familiar with these adjustments... “use an external thermal insulation composite system (ETICS), install a gas condensing boiler, etc...”I can understand ETICS... but I don’t see the gas condensing boiler as a disadvantage. Regardless of the initial costs, in my experience opinions on this vary widely.B
Bauexperte15 Oct 2015 20:16Good evening,
There is nothing wrong with ETICS in principle if a homeowner chooses this option of their own accord.
However, based on my experience with architects, ETICS is often recommended because the architect can avoid discussions about cracks appearing in the facade.
The recommendation for a gas heating system is similar. Legislators encourage and support the installation of renewable energy systems. Since these systems are still unfamiliar territory for most homeowners, they become uncertain and are easily swayed by the "experienced" architect to stick with "tried and tested" methods or their own preconceptions.
For this reason, I am curious to see how architects will promote the new energy-saving regulation with gas heating starting in January. In my opinion, an additional ventilation system alone will no longer be sufficient to meet the reference building standards.
Regards, Bauexperte
merlin83 schrieb:
I can understand the ETICS (external thermal insulation composite system)... but I don’t see the condensing gas boiler as a disadvantage. Regardless of the initial costs, in my experience opinions on this differ significantly.
There is nothing wrong with ETICS in principle if a homeowner chooses this option of their own accord.
However, based on my experience with architects, ETICS is often recommended because the architect can avoid discussions about cracks appearing in the facade.
The recommendation for a gas heating system is similar. Legislators encourage and support the installation of renewable energy systems. Since these systems are still unfamiliar territory for most homeowners, they become uncertain and are easily swayed by the "experienced" architect to stick with "tried and tested" methods or their own preconceptions.
For this reason, I am curious to see how architects will promote the new energy-saving regulation with gas heating starting in January. In my opinion, an additional ventilation system alone will no longer be sufficient to meet the reference building standards.
Regards, Bauexperte
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