ᐅ Floor Plan Optimization for a Single-Family Home with Basement on a Small Plot

Created on: 16 Sep 2019 08:38
A
AnniSke
Hello everyone!
After reading here for quite some time (and checking out nearly all floor plan questions for similar lot sizes and building dimensions), we now have some questions about the preliminary design from our builder.
Our situation is similar to the forum post from Wednesday, but our main focus is on the basement J
This is the first draft based on a rough idea of what we envision and what is important to us (the design seems quickly done to me—see the projecting dormer—or is that common nowadays?), but overall all our requests have been considered. We see room for improvement especially in the basement level, the basement stairs/daylight wells, and the size of the living/dining area (probably only fixable with a larger house footprint). The upper floor works well for us.
Independently from the builder, we came up with a similar floor plan that meets our needs; it is nothing “special” but fits our ideas well.
We would appreciate it if some of you could share practical tips or suggestions for changes so that we can respond to the builder and discuss possible deviations.
Feel free to be thorough and please also point out any potentially major planning mistakes.
I have attached the following:
  • Site plan assumed by the builder
  • Builder’s planning (floor plans, section, exterior view)
  • Our modified floor plans based on the builder’s draft (larger living/dining area, smaller kitchen, different basement stairs)

Development Plan / Restrictions

Lot size: approx. 360 m² (still not fully measured, as the plot is being subdivided)
Slope: no
Floor area ratio (FAR): 0.4
Floor space index (FSI): 0.8
Building envelope, building line and boundary: see site plan; 3 m (approx. 10 ft) on three sides, less on street side due to protected green strip with fruit trees (not our property); open building style
Edge development: no (usually allowed for townhouses, but specifically excluded for carports and garages in the development plan); edge development allowed for uncovered parking spaces
Number of parking spaces: 2
Number of stories allowed: 1-2 full stories
Roof type: gable roof (up to 38°), shed roof, flat roof (up to 25°)
Architectural style: classic-modern?
Orientation: ridge line along the street
Maximum heights / limits: eaves height max. 7.50 m (24.6 ft) above the access road (lot lies slightly below street level)
Additional requirements: none

Homeowner Requirements

Style, roof shape, building type: classic/modern detached single-family house, gable roof 38°, knee wall preferably raised to 1 m (3 ft)
Basement, number of floors: basement included, 1.5 floors
Number of people, ages: 2 (both 29), 1 child (1.5 years), at least 1 more (preferably 2) planned
Room requirements on ground floor (GF), upper floor (UF)
GF: kitchen (with sliding door, can be smaller, no separate dining area), living/dining area (currently about 32 m² (344 sq ft), our furniture is designed for this and we would like to keep it), future master bedroom, bathroom with shower (house should theoretically be usable on one level in an age-appropriate way)
UF: 3 children’s rooms, bathroom
Basement: utility room, technical room, workshop, office/guest room
Office (family use or home office?): office desired (in basement), home office at least once a week
Guests per year: about twice a month 2 people, every two weeks 1 person → guest room desired (can later be combined with office in the basement if a bedroom is needed on the ground floor)
Open or closed architecture: closed
Conservative or modern construction: rather conservative
Open kitchen, cooking island: no, smaller cooking area, separated by sliding door
Number of dining seats: permanently for 5 (current dining table has 8 seats)
Fireplace: yes, preferred
Music / stereo wall: no
Balcony, roof terrace: no
Garage, carport: no
Vegetable garden, greenhouse: some vegetable garden, so we want to place the building close to the build boundary to maximize garden space

Additional wishes / special features / daily routine, also reasons why some things should or should not be: none

House Design
Planner: planner from a building company; the second attached version is our own adjusted “solution” with the house widened by 0.5 m (approx. 1.6 ft) and furniture drawn in the living/dining and bedroom areas which we already own.
What do you especially like?: the solution with a coat area and shower niche on the ground floor, the stairs, level, masonry showers, spacious children’s rooms, fireplace location between living and dining areas, large home office/guest room in basement, where both “uses” can be nicely combined.
Why?: we had not thought of the coat and shower concept in the floor plan ideas, find it practical and reasonably age-appropriate (though the dimensions could be slightly wider), and had no clue where best to put a fireplace.
What don’t you like? Why?: living/dining area too small, at 22 m² (237 sq ft) we cannot fit our furniture, kitchen is too large, we don’t need a separate seating area in the kitchen (we currently eat all meals in the dining area), the exterior basement stairs with the bend take up too much space, and we don’t want a carport as it would have to be inside the building zone (uncovered parking is allowed as edge development), the concrete daylight wells in the basement.
  • Regarding the basement daylight wells: my father (landscape architect) suggests a landscaped slope on that side of the house instead of concrete daylight wells (I roughly marked some slope lines on our design) with stairs integrated into the slope at the rear of the house. What do you think of this option? We are unsure about stair drainage for rain, but this should be manageable with proper drainage (could be routed by pipe to the cistern we must install per development plan). Any other ideas?

Price estimate from architect/planner: not yet available, initial rough offer before planning (130 m² (1400 sq ft) with basement) was 315,000 including standard ancillary construction costs, but with a “standard basement”; we might need a waterproof concrete shell (“white tub”), estimated extra cost about 20,000 according to the builder
Personal price limit for the house: 340,000 (furniture is already owned from current large apartment (126 m² (1356 sq ft) living space), kitchen belongs to us and only needs minor changes, cost covered separately)
Preferred heating technology: we considered a ground source heat pump, but the builder has had problems twice in the building area with insufficient supply temperature and therefore recommends an air-to-water heat pump on the south side of the house. Has anyone had experience with this?

If you have to give up something, what details/features?
Can give up: dormer, large kitchen, fully heated basement
Cannot give up: basement (due to small lot and 3 children planned), bedroom on ground floor, bathroom with shower on ground floor

Why is the layout the way it is now?
Draft from planner after a brief initial discussion about our preferences (we did not provide a detailed list of requirements)
Which wishes were implemented by the architect? bedroom on ground floor, bathroom with shower, staircase design, bathroom with shower and tub on upper floor, basement with office
What do you think works well or poorly? we like the overall distribution of floors, but are not yet convinced by the basement layout.

What is the most important/basic question about the floor plan in 130 characters?
Any ideas to improve the basement (e.g., no bent stairs, maybe no basement hallway at stairs, maybe no daylight wells)? Any improvements for other floors (e.g., larger living/dining area)? Is there any place to add a laundry chute (nice to have but not essential)?

We look forward to your ideas and feedback J

Best regards and many thanks in advance!
H
haydee
28 Sep 2019 12:29
The home office and, if there are three children, the master bedroom will end up on the ground floor. Neither room needs direct sunlight, just good natural light.
11ant28 Sep 2019 12:53
Well, as I already mentioned regarding the home office: it’s better to have the option to change your view rather than just having natural light.
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D
DannSke
28 Sep 2019 18:49
11ant schrieb:

I think I may have understood the following idea (?)

Yes, but it was just a thought experiment, probably nonsense.
kaho674 schrieb:

Overall, the terrain modeling plus exterior landscaping will probably be quite expensive. I wouldn’t rely on doing it yourself unless you have garden landscapers, civil engineers, or excavator operators in the family.

We have a landscape architect in the family, but you’re right, we should definitely consider this from the start during the modeling.
kaho674 schrieb:

Did the expert say how thick the clay layer is and what lies beneath it? It all sounds very familiar. We also had problems with infiltration.

I’m attaching the layer diagram (with +10m (33 feet) construction datum assuming a manhole cover on the street). Infiltration looks poor even in the deeper layers, as far as I understood from the report. RKS1 is southwest, RKS2 northeast.
Escroda schrieb:

The ditch next to the road could have been assigned as part of the public traffic area green space, or at least as a public green area.

The ditch also runs through an existing residential area. We checked it again today; it looks very much like an overflow ditch. Wherever it’s been built over (for example, access to the allotment gardens), there’s a 300mm (12 inch) pipe underneath.
Escroda schrieb:

The access path should also be legally secured in the land register; is there anything about that in the notary contract?

The notary contract is not finished yet, but we will make sure to include that, thanks for the reminder.
haydee schrieb:

I would really raise one side of the house to create a terrace, then add stairs and a small slide down into the garden, which would be 60 to 100cm (24 to 39 inches) below street level.

That’s a really good suggestion!
kaho674 schrieb:

Well, the paths would have to be at street level already. The terrace even higher.

That’s how we were thinking about it too. Thanks for the great visualization! What software do you use?

I think we’re now really moving towards how to do this optimally and what we like very much. Many thanks for your suggestions and ideas!

Today we also spoke again with two residents living very close to the property (northwest and even lower lying), one with and one without a basement. Their opinions differed greatly, even though they are direct neighbors. The ones without a basement said they avoided it because of water. But they also excavated deeply until reaching load-bearing layers. The ones with a basement have a sump pit in the basement where water flows in and is then pumped into the sewer system (the basement lies below). They said it works well, and the pump only activates during really heavy rainfall. As far as I understand, their basement is built with masonry, then a bitumen layer, then insulation, and finally plastered again (which I find somewhat unusual).

Vertical soil profile RKS 1 with colorful soil layers, scale 1:25, labeled A.1–B.2.


Cross-section soil profile RKS 2: topsoil, claystone, signs of decomposition; scale 1:25
kaho67428 Sep 2019 19:22
Has the municipality said anything about drainage? Is a centralized drainage system available? You’re sitting on a substantial clay deposit. I wouldn’t underestimate the issue. It’s no coincidence that clay vessels were historically used to transport liquids. How do the neighbors manage drainage?
A
AnniSke
28 Sep 2019 21:38
No, a central drainage system is not planned; instead, one cistern will be built per plot (1 m3 per sealed 100 m2 (1,200 sq ft)) with regulated discharge (0.5 liters per second (0.13 gallons per second)) of the collected rainwater into the "wastewater."
DannSke schrieb:

As far as I understand, the basement is made of masonry, then a bitumen layer, then insulation, and then plastered again.
Almost – it is masonry, plastered, then treated with bitumen, and insulated afterward.

I also really like your suggestions, and this is basically what we are currently planning: to build up the front (sorry [USER=17818]@kaho674, I now know you are a huge fan of natural light), keep everything on one level, then access the ground floor via steps and go down stairs to the back where the ground level remains as is.

According to the latest calculations with the build-up, my father (who is a landscape architect ) concluded that the frost protection layer of the basement and the strip foundations would be located above the current groundwater level, so it is likely that no water management would be necessary during construction...
11ant28 Sep 2019 21:58
DannSke schrieb:

Today we also spoke again with two residents living close to the property (northwest and at a lower elevation)

Who are you referring to: neighbors in the area who also intend to build, or those next door who have already built?
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