ᐅ Single-family home with a granny flat on a 450 sqm sloped lot
Created on: 9 Feb 2022 11:44
K
Kristijan
Hello everyone,
Until now, I have only been a silent reader here, but I would like to present our own house concept for discussion. I am hoping for candid criticism, as well as your ideas and suggestions.
We are a blended family with four children (three are usually at home) and we are planning to build a single-family house with a secondary apartment in NRW. At the beginning of last year, we bought a sloped lot in a typical new development area and have since worked with an architect to develop a house concept. We designed a very simple building form (four walls and a roof) with an efficient floor plan. We sent our plans to several prefabricated house companies, asking for cost estimates, hoping that our budget might allow for potential expansion of the house. Now, faced with their offers, we have to admit that even our smallest possible floor plan exceeds our budget. The budget is about 550,000 euros for the house including additional construction costs (excluding the land). With the secondary apartment, we had hoped to double the KfW funding in the KfW 40 EE class with 67,500 euros to increase the budget. But it is what it is.
Perhaps our preliminary cost estimate was a bit naive. In any case, we are currently reconsidering the concept and are considering doing without a basement.
And now, please, fire away with your frank criticism and unvarnished truths. 🙂
Zoning Plan / Restrictions
Plot size: 450 sqm (4,844 sq ft)
Slope: Yes, north-facing slope (from the street toward south-southwest) with about 1.5 m (5 feet) elevation within the building envelope (1 meter (3 feet) within the planned footprint) rising
Floor area ratio (FAR): ?
The zoning plan does not provide this information
Building area ratio (site coverage): 0.4
Building envelope, building line and boundary: 19.5 m (64 feet) wide (street side), at the rear 17 m (56 feet) wide and 14 m (46 feet) deep
Edge development: Yes
Number of parking spaces: 2 for the main unit and 1 for the secondary apartment
Number of floors: 2.5
Roof type: Gable roof
Architectural style: Traditional
Orientation: Ridge runs from west-northwest to east-southeast
Maximum heights / limits: Maximum ridge height 9.5 m (31 feet) above finished ground floor level (this may exceed the reference street level by max. 0.5 m (1.5 feet))
Other requirements: Side setbacks 3 m (10 feet), setback from the street 3.5 m (11.5 feet)
Client Requirements
Architectural style and building type: Simple, economical building form with a gable roof
Basement, floors: Basement with secondary apartment, total 2.5 floors
Number of people, ages: Household of 5-6 people: parents aged 38 and 36, four children aged 7, 4, 2x 2 years. Family planning went a bit beyond the target and is now complete 🙂 plus grandmother in the basement apartment
Space needs on ground / upper floors: About 140-150 sqm (1,500-1,615 sq ft): kitchen, living room, 1 bedroom, 3 children’s bedrooms, 1 guest/office/patchwork room, 2 bathrooms
Utility room in the basement
Office: 1 flexible room required
Guests per year: About 10
Open or closed layout: Form follows function
Conservative or modern style: Hm, what exactly is meant here?
Open kitchen, kitchen island: Open kitchen adjacent to dining area (a kitchen island is welcome here), but closed off toward the living room
Number of dining seats: 6-8
Fireplace: No
Music / stereo wall: TV in the living room
Balcony, roof terrace: Covered terrace facing the garden with pass-through window from the kitchen
Garage, carport: Carport with green roof and additional storage space would be ideal
Vegetable garden, greenhouse: Small kitchen garden along the property boundary
House Design
Designer: Independent architect working with a prefabricated house company and DIY elements
What do you particularly like? Efficient use of space. Despite compactness, all requirements regarding space needs, especially number of rooms, are met
What do you dislike? Especially the ground floor could be more generous, the basement or storage spaces could be larger
Price estimate (according to architect): Not available
Price limit including fittings: 550,000 euros plus KfW funding if still available
Preferred heating system: Air-to-water heat pump
If you have to sacrifice something, which details or extensions would you give up?
-can give up: Reluctantly on the separate parents’ area
The secondary apartment is also under discussion
The sliding doors on the ground floor are due to a coordination error and can be removed
-can not give up: Number of rooms
Why did the design turn out the way it is?
We basically created the design ourselves. The architect later made some optimizations. Our main focus was to accommodate all room requirements within a compact floor plan on a small plot. Furthermore, as parents of four children, we wanted our own small private space.
What is the most important / fundamental question about the floor plan, summarized in 130 characters?
Is our house concept failing due to our budget expectations? What would you do differently and why?
Until now, I have only been a silent reader here, but I would like to present our own house concept for discussion. I am hoping for candid criticism, as well as your ideas and suggestions.
We are a blended family with four children (three are usually at home) and we are planning to build a single-family house with a secondary apartment in NRW. At the beginning of last year, we bought a sloped lot in a typical new development area and have since worked with an architect to develop a house concept. We designed a very simple building form (four walls and a roof) with an efficient floor plan. We sent our plans to several prefabricated house companies, asking for cost estimates, hoping that our budget might allow for potential expansion of the house. Now, faced with their offers, we have to admit that even our smallest possible floor plan exceeds our budget. The budget is about 550,000 euros for the house including additional construction costs (excluding the land). With the secondary apartment, we had hoped to double the KfW funding in the KfW 40 EE class with 67,500 euros to increase the budget. But it is what it is.
Perhaps our preliminary cost estimate was a bit naive. In any case, we are currently reconsidering the concept and are considering doing without a basement.
And now, please, fire away with your frank criticism and unvarnished truths. 🙂
Zoning Plan / Restrictions
Plot size: 450 sqm (4,844 sq ft)
Slope: Yes, north-facing slope (from the street toward south-southwest) with about 1.5 m (5 feet) elevation within the building envelope (1 meter (3 feet) within the planned footprint) rising
Floor area ratio (FAR): ?
The zoning plan does not provide this information
Building area ratio (site coverage): 0.4
Building envelope, building line and boundary: 19.5 m (64 feet) wide (street side), at the rear 17 m (56 feet) wide and 14 m (46 feet) deep
Edge development: Yes
Number of parking spaces: 2 for the main unit and 1 for the secondary apartment
Number of floors: 2.5
Roof type: Gable roof
Architectural style: Traditional
Orientation: Ridge runs from west-northwest to east-southeast
Maximum heights / limits: Maximum ridge height 9.5 m (31 feet) above finished ground floor level (this may exceed the reference street level by max. 0.5 m (1.5 feet))
Other requirements: Side setbacks 3 m (10 feet), setback from the street 3.5 m (11.5 feet)
Client Requirements
Architectural style and building type: Simple, economical building form with a gable roof
Basement, floors: Basement with secondary apartment, total 2.5 floors
Number of people, ages: Household of 5-6 people: parents aged 38 and 36, four children aged 7, 4, 2x 2 years. Family planning went a bit beyond the target and is now complete 🙂 plus grandmother in the basement apartment
Space needs on ground / upper floors: About 140-150 sqm (1,500-1,615 sq ft): kitchen, living room, 1 bedroom, 3 children’s bedrooms, 1 guest/office/patchwork room, 2 bathrooms
Utility room in the basement
Office: 1 flexible room required
Guests per year: About 10
Open or closed layout: Form follows function
Conservative or modern style: Hm, what exactly is meant here?
Open kitchen, kitchen island: Open kitchen adjacent to dining area (a kitchen island is welcome here), but closed off toward the living room
Number of dining seats: 6-8
Fireplace: No
Music / stereo wall: TV in the living room
Balcony, roof terrace: Covered terrace facing the garden with pass-through window from the kitchen
Garage, carport: Carport with green roof and additional storage space would be ideal
Vegetable garden, greenhouse: Small kitchen garden along the property boundary
House Design
Designer: Independent architect working with a prefabricated house company and DIY elements
What do you particularly like? Efficient use of space. Despite compactness, all requirements regarding space needs, especially number of rooms, are met
What do you dislike? Especially the ground floor could be more generous, the basement or storage spaces could be larger
Price estimate (according to architect): Not available
Price limit including fittings: 550,000 euros plus KfW funding if still available
Preferred heating system: Air-to-water heat pump
If you have to sacrifice something, which details or extensions would you give up?
-can give up: Reluctantly on the separate parents’ area
The secondary apartment is also under discussion
The sliding doors on the ground floor are due to a coordination error and can be removed
-can not give up: Number of rooms
Why did the design turn out the way it is?
We basically created the design ourselves. The architect later made some optimizations. Our main focus was to accommodate all room requirements within a compact floor plan on a small plot. Furthermore, as parents of four children, we wanted our own small private space.
What is the most important / fundamental question about the floor plan, summarized in 130 characters?
Is our house concept failing due to our budget expectations? What would you do differently and why?
Kristijan schrieb:
Are there any comments so far on the overall concept:Yes, currently I see 4 bedrooms + a children’s bathroom + utility room in the basement. In the upper floor, there is a living area, bedroom, bathroom + guest toilet. I would invest in the staircase to access the attic, even if it is not going to be finished initially—just for storage for now. I would skip the dressing room in favor of the living area. To be continued. Good night.... 🙂
K a t j a schrieb:
@11ant: Isn’t the design already exceeding the floor area ratio of 0.4 with 450m² (4844 sq ft) across 3 floors? Is something not being counted here? I’m a bit confused. Could you please clarify? I believe that basements are not included, as long as they are not full stories (?). @Escroda is missing :-(
Kristijan schrieb:
At least I’ll sit down and start working on a floor plan, which I will then post here for discussion. Just to remind you, I recommended not to start again halfway through the process—that is, not in design phase 3. You mentioned that you and the architect had developed a concept. Based on that, I would suggest making adjustments: how do the prices of the quotes compare to the “target price”?
Maybe my advice from two weeks ago in another thread about a family with a similar number of children will also help you: https://www.hausbau-forum.de/threads/grundriss-fuer-efh-mit-4-5-kinderzimmern.42442/page-2#post-553963
https://www.instagram.com/11antgmxde/
https://www.linkedin.com/company/bauen-jetzt/
K
Kristijan10 Feb 2022 10:31K a t j a schrieb:
Yes, currently I see 4 bedrooms + kids’ bathroom + utility room in the basement. On the upper floor, there is a common living area, bedroom, bathroom + guest toilet. I would invest the money in the staircase to access the attic, even if there is no immediate plan for finishing it. Initially only for storage. I would forgo the walk-in closet in favor of the common living area. To be continued. Good night.... 🙂 Good morning,
thank you very much for the suggestions. I might only be able to fit three bedrooms in the basement unless I make the floor area significantly larger. The twins could share a room at first and move to their own rooms under the roof later.
Would you plan the main entrance on the lower floor or provide access to the upper floor via an external staircase?
K
Kristijan10 Feb 2022 11:0511ant schrieb:
Maybe my advice from two weeks ago in another thread for a family with a similar child situation could help you as well: https://www.hausbau-forum.de/threads/grundriss-fuer-efh-mit-4-5-kinderzimmern.42442/page-2#post-553963 I understand your suggestion as planning two separate residential units on the two levels you proposed (building with a basement, forgoing the first upper floor), or at least pre-installing for a second independent unit. This would allow renting one unit later when less space is needed (for example, when the children move out).
But maybe I’m missing something. The night with the twins was tough.
11ant schrieb:
I advised not to start again right in the middle of the process: that is, not in design phase 3. You mentioned that you developed a concept with your architect. Based on that, I would suggest adjusting: how do the prices of the offers compare to the “target price”? The target budget for the house builders was each 500,000 euros for constructing the house as a KfW 40 EE or NH house, building the basement, and fully finishing all three levels. The remaining budget of 50,000 euros was planned together with the grant for earthworks, landscaping, and the kitchen.
All providers indicated in preliminary talks that this might work out. However, a detailed calculation was needed first.
Before receiving the offers, we still saw some savings potential in subcontracting certain trades and omitting the planned sliding doors on the ground floor.
Our current offers range between 540,000 euros and 620,000 euros for building the house according to our specifications. Earthworks and landscaping would be additional here.
In our case, the architect did not charge according to HOAI, but the builder suggested agreeing on a fee-based planning contract. Accordingly, the independent architect, who regularly collaborates with the builder, met with us onsite once and revised our plans during two further meetings. The costs were modest and accounted for less than one-sixth of the fee expected for design phase 5, based on a project volume of 500,000 euros.
We are currently having our offers independently evaluated for value for money, as we lack the expertise to compare different wall constructions and to understand where additional costs are justified.
The resulting ranking would also be used when preparing an offer for another house design.
It remains uncertain whether the architect would be willing to make further modifications or design an entirely new house given the current circumstances. My idea was to pre-plan now so that her effort would hopefully remain limited. I will definitely follow up to see if she is open to “adjustments.”
Kristijan schrieb:
Would you plan access to the house on the lower floor or via an external staircase to the upper level?I’m currently struggling with the floor area ratio and the single-storey concept. This is really just a layman’s opinion, but if I understand correctly, in your case the upper floor, of which a quarter is under 2.30m (7.5 ft) height, does not count as a full storey. So, with a knee wall height of 1.80m (5.9 ft), a roof pitch of 20°, and a house depth of 10m (33 ft), the upper floor probably wouldn’t be considered a full storey. I would increase the base floor area and accept the sloped ceilings upstairs. It would look something like this:But I honestly don’t know if this works with the attic floor. I need to recalculate and research that again.
The granny flat and everything else is completely out.
Oh, there are still windows missing at the bottom edge of the attic floor plan.
K
Kristijan10 Feb 2022 12:16@K a t j a
Wow, really impressive!!! How did you manage to do that in such a short time? I would probably have only managed to get the exterior walls up. Thanks a lot.
It looks very harmonious already.
I’m leaning towards extending the house along the street side a bit while making it narrower. That way, there would still be some space left in the already quite small garden.
Regarding the floor area ratio, we shouldn’t have any issues since the development plan allows for two full stories. Or does that not matter here? My idea would be to design the roof much steeper to have additional space for expansion in the attic. However, that would mean modifying the staircase situation again. I will give it a try now as well.
Wow, really impressive!!! How did you manage to do that in such a short time? I would probably have only managed to get the exterior walls up. Thanks a lot.
It looks very harmonious already.
I’m leaning towards extending the house along the street side a bit while making it narrower. That way, there would still be some space left in the already quite small garden.
Regarding the floor area ratio, we shouldn’t have any issues since the development plan allows for two full stories. Or does that not matter here? My idea would be to design the roof much steeper to have additional space for expansion in the attic. However, that would mean modifying the staircase situation again. I will give it a try now as well.
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