ᐅ Floor plan, post-and-beam construction, accessory dwelling unit, and existing building
Created on: 21 Feb 2023 20:48
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BucheOnBoard
Hello everyone,
Currently, my father, my wife, and my child (under 1 year old) live in a small residential house from the 1950s with 61m² (655 sq ft) of living space. The property is owned 50/50 by my father and me but is still partly being paid off by my grandmother (my outstanding payments are held in a separate account and are therefore just a “pass-through” item, while my father pays his monthly installments from his income). The plot is in Hamburg Iserbrook and measures 681m² (7,333 sq ft) with a standard land value of €985.
Unsurprisingly, the space is becoming somewhat tight, even though we get along well. Furthermore, the health of the older housemate is declining, and the narrow staircase to the upper floor is already becoming difficult to manage.
The basic idea is this: I would receive the second half of the plot as a gift, debt-free. My father will continue paying off his installments until he inherits the remainder. In return, we will build him a nice accessory apartment with the corresponding right of residence (or usufruct right, which still needs to be clarified)—barrier-free and compact so he can live independently there for as long as possible. The rest of the ground floor would then only contain a multipurpose room, guest toilet, and hallway; upstairs four rooms and a bathroom. We would like a (simple) converted attic as a retreat area. To relieve the ground floor space and avoid fully using the building envelope (sealing of surfaces, etc.), we plan a basement, as there are also two space-intensive hobbies and a workshop desired for DIY projects. I will also build some of the furniture myself.
Now to the questionnaire:
Building Plan / Restrictions
Plot size: 681m² (7,333 sq ft) with existing house
Slope: No, but the area from the street level up to the terrace is filled +90cm (35 inches), the garage is at about +40cm (16 inches), the neighboring plot to the north also about +40cm (16 inches), and to the south approximately at street level
Floor area ratio (FAR): 0.4
Plot ratio (building coverage ratio): 0.4
Building envelope, building line, and boundaries: 5m (16.4 ft) setback to the street, then 15m (49.2 ft) deep, 2.5m (8.2 ft) setback on each side (more for taller buildings)
Edge development: Allowed (garages etc., max. wall height 3m (10 ft), max. length 9m (30 ft))
Number of parking spaces: We believe none are legally required; we plan to provide one for future use, for electric vehicle charging (currently not needed)
Number of floors: One full story; ALKIS shows some buildings apparently with two floors (see attachment)
Roof type: Not specified
Architectural style: Not specified
Orientation: Not specified
Maximum heights/limits: Not specified
Other requirements: No illuminated advertising signs 😉
The 1965 building plan mainly mandates “residential zoning only” and “one full story,” but even these rules seem flexible. There is a very large copper beech tree in the southeast corner of the plot, with an estimated crown diameter of 10m (33 ft) and at least 12-14m (39-46 ft) tall. The tree is to be preserved (it is unclear if it must officially be preserved with a new build). I expect that the new building must not come closer to the tree than the current building—about 2.5m (8.2 ft) from the trunk. The trunk itself is roughly 1.5m (5 ft) in diameter. A pruning plan is under discussion (also due to shading of the roof, planned for solar panels).
Owners' Requirements
Architectural style, roof shape, building type: Detached single-family home, gable roof with pitch >45°, rather long and narrow
Basement, number of floors: Yes to basement, 1.5 floors plus a converted attic
Number of occupants, ages: 4 (64 (gruff and private), 34, 31, under 1) Another child should be possible
Ground floor space needs: Open-plan area preferably with a small pantry, guest toilet
Accessory apartment with barrier-free design (walk-in shower, open living kitchen with sleeping niche). Can be small.
Shared hallway important (for potential care needs without going outside, access to joint basement with laundry facilities, etc.)
Upper floor space needs: 1 bedroom with a large bed and built-in closets but no extras, 3 rooms (1 child’s room, 1 office/child’s room, 1 guest/office (can be small)), 1 bathroom with a larger vanity, bathtub, and shower
Attic space needs: 2 “retreat” areas for the adults; if necessary, just a rocking chair with reading lamp and sewing machine on one side, and a gaming PC on the other. The current attic is an equilateral triangle with 2.1m (83 inches) side length; it doesn’t need to be much larger/wider/higher than that.
Basement space needs (access via shared hallway + additional exterior entrance): Technical room with heat pump, ventilation, electrical distribution, inverter, server; woodwork workshop; laundry room; 2 hobby cellars for large-format collections—Lego and beer cans, no kink-shaming please 😉 ; 1 storage room for decorations, suitcases, camping gear, etc. Must be heated (and ventilated), but simple tile flooring and surface-mounted installations are sufficient.
Office: Family use or home office? Home office about three times a week, plus one self-employed side business
Guest stays per year: 6–10, usually just one night, sometimes 2–3 nights
Open or closed design: Open on the ground floor but staircase not located in the living room/open space
Conservative or modern construction? I’m never quite sure of the difference, but I feel fully modern
Open kitchen, kitchen island: Yes, cooking often and joyfully, also with guests
Number of dining seats: 6; existing table extends to 14 seats for Christmas and birthdays
Fireplace: No, no chimney planned
Music/stereo wall: No
Balcony, roof terrace: No
Garage, carport: Carport/roof overhang directly at the building would be good, mainly for bikes and potentially for an electric vehicle in the (near) future. To my knowledge, Hamburg does not require parking spaces.
Vegetable garden, greenhouse: Maybe a small bed later, but not important at the moment
Other wishes/particularities/daily routine, including reasons for certain choices: Currently, leisure activities happen at the dining table, which is between sofa and TV (used about once a week), so large lounge furniture is not really needed. The tree is a critical factor, as it likely narrows the building envelope in the front area to about 6.5m (21 ft). We don’t want to move the house further back because of the garden.
House Design
Planner: Still in the very early idea phase. Overall, we think about 180m² (1,937 sq ft) of living space plus basement. We currently live as four on 61m² (655 sq ft) and can manage. We don’t need huge increases in room size, rather a spatial separation with the accessory apartment and space for hobbies and home office. Dressing rooms or a children’s bathroom are not planned.
Personal budget limit for house including fittings: €750,000–800,000 (USD amount varies), with much furniture available from the existing house. Demolition cost would be extra, but I see plenty of grants and rental expenses during construction period. €450,000 (about $480,000) equity is available; the plot described above would be fully paid off (worth almost €700,000 or approximately $750,000).
Preferred heating technology: Ground-source heat pump with deep borehole and 12–15kWp photovoltaic system plus centralized controlled residential ventilation with enthalpy heat exchanger
If you have to compromise, on which features/extensions
- What can you do without: Either attic conversion or guest-office room
- What you cannot do without: Basement
Why is the design like this? No design yet; we are still considering the orientation on the plot.
It will be a timber frame construction, a gable roof to fit well, knee wall about 1.3m (4.3 ft), roof pitch >45°. The current roof is 60° and gives it a rustic fairy-tale look. On the south side, we want nearly full photovoltaic coverage except for a few roof windows; on the north side, we can imagine a dormer also to integrate the staircase to the attic—maybe a cross-gable?
The rough idea is close to the volume of a Danwood Point 138.1, but a bit wider and longer, and “narrower at the front” (the east side facing the street) due to the tree. Plus an attic conversion with a steeper roof. Access via staircase on the north side.
Alternatively, separate accessory apartment in the south and main residence in the north, but that would split the already narrow house into even narrower parts.
We would like a local timber frame general contractor (any recommendations in the greater Hamburg area?).
Am I completely off track? Have I forgotten anything? Made any major mistakes besides not building three years ago? Are important details missing? Will it all turn out too cramped? Is the budget roughly realistic? Aside from a garden shed, I have no building experience but some electrical knowledge. Photovoltaics and networking could be done by me, full electrical installation I am allowed but would not be practical with a general contractor.
Or is the program so complex that an architect is absolutely necessary because a draftsman would be overwhelmed? From my research it seems that architects for single-family homes that are not villas are quite rare.
Thanks to everyone who made it this far! And even more thanks to those who share their opinions or ideas.
Attached are current ALKIS excerpt, aerial photo, and building plan excerpt, all oriented north and approximately the same section. I hope they are legible… Red borders and points mark the plot.
Currently, my father, my wife, and my child (under 1 year old) live in a small residential house from the 1950s with 61m² (655 sq ft) of living space. The property is owned 50/50 by my father and me but is still partly being paid off by my grandmother (my outstanding payments are held in a separate account and are therefore just a “pass-through” item, while my father pays his monthly installments from his income). The plot is in Hamburg Iserbrook and measures 681m² (7,333 sq ft) with a standard land value of €985.
Unsurprisingly, the space is becoming somewhat tight, even though we get along well. Furthermore, the health of the older housemate is declining, and the narrow staircase to the upper floor is already becoming difficult to manage.
The basic idea is this: I would receive the second half of the plot as a gift, debt-free. My father will continue paying off his installments until he inherits the remainder. In return, we will build him a nice accessory apartment with the corresponding right of residence (or usufruct right, which still needs to be clarified)—barrier-free and compact so he can live independently there for as long as possible. The rest of the ground floor would then only contain a multipurpose room, guest toilet, and hallway; upstairs four rooms and a bathroom. We would like a (simple) converted attic as a retreat area. To relieve the ground floor space and avoid fully using the building envelope (sealing of surfaces, etc.), we plan a basement, as there are also two space-intensive hobbies and a workshop desired for DIY projects. I will also build some of the furniture myself.
Now to the questionnaire:
Building Plan / Restrictions
Plot size: 681m² (7,333 sq ft) with existing house
Slope: No, but the area from the street level up to the terrace is filled +90cm (35 inches), the garage is at about +40cm (16 inches), the neighboring plot to the north also about +40cm (16 inches), and to the south approximately at street level
Floor area ratio (FAR): 0.4
Plot ratio (building coverage ratio): 0.4
Building envelope, building line, and boundaries: 5m (16.4 ft) setback to the street, then 15m (49.2 ft) deep, 2.5m (8.2 ft) setback on each side (more for taller buildings)
Edge development: Allowed (garages etc., max. wall height 3m (10 ft), max. length 9m (30 ft))
Number of parking spaces: We believe none are legally required; we plan to provide one for future use, for electric vehicle charging (currently not needed)
Number of floors: One full story; ALKIS shows some buildings apparently with two floors (see attachment)
Roof type: Not specified
Architectural style: Not specified
Orientation: Not specified
Maximum heights/limits: Not specified
Other requirements: No illuminated advertising signs 😉
The 1965 building plan mainly mandates “residential zoning only” and “one full story,” but even these rules seem flexible. There is a very large copper beech tree in the southeast corner of the plot, with an estimated crown diameter of 10m (33 ft) and at least 12-14m (39-46 ft) tall. The tree is to be preserved (it is unclear if it must officially be preserved with a new build). I expect that the new building must not come closer to the tree than the current building—about 2.5m (8.2 ft) from the trunk. The trunk itself is roughly 1.5m (5 ft) in diameter. A pruning plan is under discussion (also due to shading of the roof, planned for solar panels).
Owners' Requirements
Architectural style, roof shape, building type: Detached single-family home, gable roof with pitch >45°, rather long and narrow
Basement, number of floors: Yes to basement, 1.5 floors plus a converted attic
Number of occupants, ages: 4 (64 (gruff and private), 34, 31, under 1) Another child should be possible
Ground floor space needs: Open-plan area preferably with a small pantry, guest toilet
Accessory apartment with barrier-free design (walk-in shower, open living kitchen with sleeping niche). Can be small.
Shared hallway important (for potential care needs without going outside, access to joint basement with laundry facilities, etc.)
Upper floor space needs: 1 bedroom with a large bed and built-in closets but no extras, 3 rooms (1 child’s room, 1 office/child’s room, 1 guest/office (can be small)), 1 bathroom with a larger vanity, bathtub, and shower
Attic space needs: 2 “retreat” areas for the adults; if necessary, just a rocking chair with reading lamp and sewing machine on one side, and a gaming PC on the other. The current attic is an equilateral triangle with 2.1m (83 inches) side length; it doesn’t need to be much larger/wider/higher than that.
Basement space needs (access via shared hallway + additional exterior entrance): Technical room with heat pump, ventilation, electrical distribution, inverter, server; woodwork workshop; laundry room; 2 hobby cellars for large-format collections—Lego and beer cans, no kink-shaming please 😉 ; 1 storage room for decorations, suitcases, camping gear, etc. Must be heated (and ventilated), but simple tile flooring and surface-mounted installations are sufficient.
Office: Family use or home office? Home office about three times a week, plus one self-employed side business
Guest stays per year: 6–10, usually just one night, sometimes 2–3 nights
Open or closed design: Open on the ground floor but staircase not located in the living room/open space
Conservative or modern construction? I’m never quite sure of the difference, but I feel fully modern
Open kitchen, kitchen island: Yes, cooking often and joyfully, also with guests
Number of dining seats: 6; existing table extends to 14 seats for Christmas and birthdays
Fireplace: No, no chimney planned
Music/stereo wall: No
Balcony, roof terrace: No
Garage, carport: Carport/roof overhang directly at the building would be good, mainly for bikes and potentially for an electric vehicle in the (near) future. To my knowledge, Hamburg does not require parking spaces.
Vegetable garden, greenhouse: Maybe a small bed later, but not important at the moment
Other wishes/particularities/daily routine, including reasons for certain choices: Currently, leisure activities happen at the dining table, which is between sofa and TV (used about once a week), so large lounge furniture is not really needed. The tree is a critical factor, as it likely narrows the building envelope in the front area to about 6.5m (21 ft). We don’t want to move the house further back because of the garden.
House Design
Planner: Still in the very early idea phase. Overall, we think about 180m² (1,937 sq ft) of living space plus basement. We currently live as four on 61m² (655 sq ft) and can manage. We don’t need huge increases in room size, rather a spatial separation with the accessory apartment and space for hobbies and home office. Dressing rooms or a children’s bathroom are not planned.
Personal budget limit for house including fittings: €750,000–800,000 (USD amount varies), with much furniture available from the existing house. Demolition cost would be extra, but I see plenty of grants and rental expenses during construction period. €450,000 (about $480,000) equity is available; the plot described above would be fully paid off (worth almost €700,000 or approximately $750,000).
Preferred heating technology: Ground-source heat pump with deep borehole and 12–15kWp photovoltaic system plus centralized controlled residential ventilation with enthalpy heat exchanger
If you have to compromise, on which features/extensions
- What can you do without: Either attic conversion or guest-office room
- What you cannot do without: Basement
Why is the design like this? No design yet; we are still considering the orientation on the plot.
It will be a timber frame construction, a gable roof to fit well, knee wall about 1.3m (4.3 ft), roof pitch >45°. The current roof is 60° and gives it a rustic fairy-tale look. On the south side, we want nearly full photovoltaic coverage except for a few roof windows; on the north side, we can imagine a dormer also to integrate the staircase to the attic—maybe a cross-gable?
The rough idea is close to the volume of a Danwood Point 138.1, but a bit wider and longer, and “narrower at the front” (the east side facing the street) due to the tree. Plus an attic conversion with a steeper roof. Access via staircase on the north side.
Alternatively, separate accessory apartment in the south and main residence in the north, but that would split the already narrow house into even narrower parts.
We would like a local timber frame general contractor (any recommendations in the greater Hamburg area?).
Am I completely off track? Have I forgotten anything? Made any major mistakes besides not building three years ago? Are important details missing? Will it all turn out too cramped? Is the budget roughly realistic? Aside from a garden shed, I have no building experience but some electrical knowledge. Photovoltaics and networking could be done by me, full electrical installation I am allowed but would not be practical with a general contractor.
Or is the program so complex that an architect is absolutely necessary because a draftsman would be overwhelmed? From my research it seems that architects for single-family homes that are not villas are quite rare.
Thanks to everyone who made it this far! And even more thanks to those who share their opinions or ideas.
Attached are current ALKIS excerpt, aerial photo, and building plan excerpt, all oriented north and approximately the same section. I hope they are legible… Red borders and points mark the plot.
BucheOnBoard schrieb:
We had already communicated that no car is supposed to be parked in the carport, but that maybe one day an electric car would be charged there, so I would definitely not base the quotation marks on that. Staying overnight at a hotel because the charging car blocks the emergency exit is categorically a definite no-go, and in my opinion the complete opposite of a minor, pardonable planning oversight, which rather earns its quotation marks in gold and on a ribbon.
BucheOnBoard schrieb:
The beech tree is also the main reason for the setback: otherwise, the canopy would be too close and would require annual pruning due to the little space for yearly growth. We said that a bay window (at least a projection not extending across the full width of the house) could be quite practical for that. Now this has turned into more or less a “clumsy cutting off of the upper floor” – which additionally doesn’t work because the southeast corner is too close to the trunk. We discussed this again yesterday with “our” arborist, who assumes that this solution would not be approved or that the tree maintenance requirements would be extremely complex. Using a pressure washer to clean sticky pollen off the flat roof is also not ideal. Unfortunately, I can also imagine that aspects related to avoiding a full upper floor are a reason for the ground floor extension.
hanghaus2023 schrieb:
Some time ago, we had a case where someone had to build a house around an oak tree. The plot was much smaller. Nevertheless, I remember the situation https://www.hausbau-forum.de/threads/grundriss-schlauchhaus-l-form-dreieckiges-grundstueck-samt-eiche.29277/ as less complicated.
ypg schrieb:
The most obvious solution would be to reduce the attic size by cutting back the roof. This has always been done instead of creating an expensive flat roof: without a knee wall or by building a small knee wall inside and using the walls for built-in cupboards. In my opinion, knee walls are definitely advisable here, because considering the roof pitch any knee wall height would be deadly. Whether a knee wall with built-in cupboards would help avoid a full floor is highly doubtful. I rather see knee walls without usable storage spaces.
@BucheOnBoard: please provide all floor plans and a cross-section of the existing building, as well as elevations of the design from post #39. I see a missed opportunity in design phase 1 to include the assessment of the existing building’s structural upgrade. From my perspective, the construction task is to create space for the next generation and opportunities for family members to avoid each other or retreat as needed. Treating the existing building—which is currently inhabited and already home to future users—blanketly as to be demolished seems, to put it mildly, impractical and by no means automatically justified by a basement in need of renovation. Besides, it is an unnecessarily expensive exercise that increases the planner’s fee basis. The connection between demolition and fees almost reminds me of a dental procedure ;-)
Have the framework conditions of the zoning plan / building permit been mentioned here yet?
https://www.instagram.com/11antgmxde/
https://www.linkedin.com/company/bauen-jetzt/
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BucheOnBoard23 Oct 2023 12:40First of all, we are quite in love with the layout of the latest design by @K a t j a. From a first-build perspective, the room layout and the position of the stairs feel like a good direction. However, the overall sense is that it still needs to be a bit smaller for the budget, and perhaps the front part could be narrower. I will try to get further clarification on this.
Otherwise, correct me if I’m mistaken, but in Hamburg, adding a knee wall (dormer wall) does not change the number of floors at all. The area with a height over 2.3m (7 ft 7 in) may only be two-thirds of the floor below. Whether the space under 2.3m (7 ft 7 in) consists of a large knee wall and a shallow roof pitch (similar to a townhouse), or runs down to 0cm (0 inches) without a knee wall or dormer, or is "not there at all" (stepped storey), makes no difference.
@11ant The zoning plan was already mentioned in the first post (with the almost only important information being “one full storey”). I have also repeatedly pointed out that it’s not just the damp basement. It doesn’t necessarily have to be a flat roof that needs pressure washing; a shallow monopitch roof (more space for photovoltaics), a balcony, or a green roof are also possible.
I’ve attached the elevations, although the measurements for the beech tree were provided, it is not drawn correctly—the tree is 16–18m (52–59 ft) tall, not about 12m (39 ft) as shown in the drawings. The trunk diameter right above the ground is approximately 1.5m (5 ft), which is what I meant by “terrace in the beech tree” — the drawing extends into the trunk, not just to the canopy dripline area.
Otherwise, correct me if I’m mistaken, but in Hamburg, adding a knee wall (dormer wall) does not change the number of floors at all. The area with a height over 2.3m (7 ft 7 in) may only be two-thirds of the floor below. Whether the space under 2.3m (7 ft 7 in) consists of a large knee wall and a shallow roof pitch (similar to a townhouse), or runs down to 0cm (0 inches) without a knee wall or dormer, or is "not there at all" (stepped storey), makes no difference.
@11ant The zoning plan was already mentioned in the first post (with the almost only important information being “one full storey”). I have also repeatedly pointed out that it’s not just the damp basement. It doesn’t necessarily have to be a flat roof that needs pressure washing; a shallow monopitch roof (more space for photovoltaics), a balcony, or a green roof are also possible.
I’ve attached the elevations, although the measurements for the beech tree were provided, it is not drawn correctly—the tree is 16–18m (52–59 ft) tall, not about 12m (39 ft) as shown in the drawings. The trunk diameter right above the ground is approximately 1.5m (5 ft), which is what I meant by “terrace in the beech tree” — the drawing extends into the trunk, not just to the canopy dripline area.
BucheOnBoard schrieb:
Please correct me if I’m misunderstanding, but in Hamburg, adding a knee wall does not affect the number of stories in any way. The floor area with a ceiling height above 2.3m (7.5 ft) may only cover two-thirds of the story below. Whether the section below 2.3m (7.5 ft) consists of a large knee wall and a shallow roof pitch (like a town villa), or slopes down to 0cm without a knee wall or dormer, or is “not there at all” (setback story), does not matter at all. In the present case (>45° roof pitch), even a small knee wall increases the share of the area above 2.3m (7.5 ft).
https://www.instagram.com/11antgmxde/
https://www.linkedin.com/company/bauen-jetzt/
BucheOnBoard schrieb:
First of all, we are quite in love with the layout of the latest design by @K a t j a,Yes, it’s great! However, by moving the entrance, does that mean the workshop is no longer included? BucheOnBoard schrieb:
Otherwise, correct me if I’m wrong, but in Hamburg adding a knee wall (dormer wall) does not change the number of floors at all. The living space with a ceiling height over 2.3m (7 ft 7 in) can only cover two-thirds of the floor area underneath. It doesn’t matter whether the part under 2.3m (7 ft 7 in) consists mostly of knee walls and a shallow roof pitch (like a town villa), or slopes down to 0cm (0 inches) with no knee wall (dormer wall) — or if that area simply doesn’t exist at all (as in a stepped floor).Then compare the sections with the same roof but different knee wall heights. The higher the roof starts, the more space over 2.3m (7 ft 7 in) you get. And you shouldn’t compare a town villa, stepped floor, and a hipped roof because you are planning an attic.
BucheOnBoard schrieb:
First of all, we are somewhat smitten with the layout of the latest draft by @K a t j a. From a building feel perspective, the room arrangement and stair position seem like a good approach. I’ll start working on the calculations… 😉
By the way, I just noticed that the kitchen sliding door is missing.
BucheOnBoard schrieb:
- the feeling also says that overall it would still need to be somewhat smaller to fit the budget, and possibly the front part could be even narrower, For the granny flat, you can definitely save at least half a meter. The 10.60m (35 ft) at the top of the plan could probably be reduced by another 20 to 30cm (8 to 12 inches). That depends on the size of the closet near the entrance and, above all, on the space required for the utility room.
BucheOnBoard schrieb:
but I’ll try to clarify that again. From whom?
K a t j a schrieb:
You can definitely save about half a meter more on the granny flat. How large is it? For official funding, at least 30 sqm (about 323 sq ft) is required, as far as I know.
K a t j a schrieb:
Space requirements in the utility room And how big is it? For the house on the slope, it was only about 6.5 sqm (about 70 sq ft). I find that a bit tight, even with a pantry included.
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