Ackerbürgerhäuschen

Maria-Dorothea-Str. 2

91161

Hilpoltstein, Germany

Architect

Stefan Lerzer
Rennbahnstr. 1, 92318 Neumarkt i. d. Opf.
info@lerzer-ip.de
09181 - 270 590

Owner

Monika und Thomas Fritsch
Kreichwichstr. 2, 92342 Freystadt

Contact Details

Alexandra Troi
Hochschule Coburg
alexandra.troi@hs-coburg.de

Other Information

Related publications
https://www.kfw.de/stories/gesellschaft/bauen/restaurierter-altbau-zweiter-platz/
KfW: The former ruin has become a handsome, well-inhabitable house.
The „Ackerbürgerhäuschen“ is located in middle Franconia and was built around 1400. The building is listed for preservation and is situated in the old town of Hilpoltstein, which is listed as well. During the renovation of the Ackerbürgerhäuschen in 2016, Monika and Thomas Fritsch set themselves the goal of preserving not only the possibly 1,000-year-old cellar vault, but also the outer wall made of sandstone and the oak beams of the framework and roof truss. The house got the KfW Award “Bauen und Wohnen 2016” because of the excellent energetic renovation.
Energy performance
61,94 kWh/m2.y

Climate Zone warm-gemäßigte Klimazone

Altitude 384 m a.s.l.

HDD 2401

CDD 592

Protection level Listed

Conservation Area:
Yes

Level of Protection:
Denkmalschutz / Listed Building

Building age before 1600

Year of last renovation:
2015

Year of previous renovation:
0

Building use Residential (rural)

Secondary use:
NA

Building occupancy:
Permanently occupied

Number of occupants/users:
3

Building area Net floor area [m²]: 207,5

Building typology:
Detached house

Number of floors:
2

Basement yes/no:
Yes

Number of heated floors:
2

Gross floor area [m²]:
283,0

Thermal envelope area [m²]:
484,25

Volume [m³]:
648,5

NFA calculation method:
NGF (de)

Construction type
Stone masonry wall

External finish:
Rendered

Internal finish:
Plastered (on hard)

Roof type:
Pitched roof

+ MORE - LESS
KfW: The former ruin has become a handsome, well-inhabitable house.
KfW: The former ruin has become a handsome, well-inhabitable house.
KfW: the new entrance area on the west side of the building
KfW: the new entrance area on the west side of the building
KfW: micro-apartment first floor
KfW: micro-apartment first floor
KfW: micro-apartment first floor
KfW: micro-apartment first floor
KfW: micro-apartment first floor
KfW: micro-apartment first floor
LERZER ING+Plan GmbH: view from south
LERZER ING+Plan GmbH: view from south
LERZER ING+Plan GmbH: Roof truss
LERZER ING+Plan GmbH: Roof truss

RENOVATION PROCESS

Architecture

BUILDING DESCRIPTION

The Ackerbürgerhäuschen has one floor and is connected to the side of the eaves. The entrance door is placed in the middle of the west side. Besides the entrance door there are two windows right and two windows left. The outside walls are built of sandstone, except for a wide piece of wall on the east side – consisting of breeze block. On the southern gable end, there are two windows on the first floor and two on the second floor. There is also a window in the attic floor. On the east side there are several windows. The north-side gable end has just a door on the ground floor. Under the north-side half of the house there is a barrel vaulting with oriented to the north-south direction. The roof truss consists of a double standing truss with a conveyor in the west-east direction and a knee brace in the north-south direction. The south gable, consisting of sandstone, was original planked. The north gable consists of bricks. The floor on the upper floor consists largely of floorboards.
Urban context
The Ackerbürgerhäuschen is located in the old town of Hilpoltstein in the area of the castle. Opposite of the house there is a church. Because of this position the house is attended as a representative building of the city.

HERITAGE SIGNIFICANCE

ELEMENTS WORTHY OF PRESERVATION
In addition to the barrel vaulting with sandstone in the basement, the outside walls with sandstone and the oak beams of the roof truss are considered worthy of preservation. The trees for the roof truss were felled between 1396 and 1408
Heritage Value Assesment
The Ackerbürgerhäuschen is very important for the local culture, because of the roof truss which is the oldest in the district. The house was expanded and rebuilt over several decades. In the course of a planned reconstruction work, dendrochronological measures were conducted in 1998. Thus, it could be determined that there was a tower on the property. The tower could be assigned to the Romanesque period due to the arch-entrance, the stone offset and the clean arch of the vault. After the demolition of the tower, a ring wall was built at the same place. The breastwork? (Brustwehr) of the ring wall served as an essential eaves side wall when building the new house in 1396. After the abandonment of the outer castle area in 1407/08, the existing house was rebuilt to a residential house. After the renovation process further modifications followed for example the renewing of the outside walls in sandstone and the expansion of the ground floor and the attic room.

State of repair

Conditions of the envelope
The eyesore of Hilpolstein: Before Thomas and Monika Fritsch bought the building, the house was empty for twenty years. The plaster was barely visible. Also, the roof truss was in a very bad condition.
Description of pre-intervention building services
The last known inhabitants had only running water. Sanitary installations such as toilets and shower didn´t exist. It was a ramshackle cottage with an outside toilet in the backyard and a charcoal oven.

Aim of retrofit

Renovation
The renovation should not only preserve a historic building in the listed old town of Hilpoltstein, but also revitalize the old town by creating new living space. The eyesore in the centre of the village should disappear and appear in new splendour. During the renovation, attention was paid to the barrier poverty. This was successfully implemented by a barrier-free sanitary area, the avoidance of thresholds and the installation of barrier-free doors. Due to the fact that only little usable building fabric was left of the existing building after years of vacancy, an attempt was made to preserve this building fabric as far as possible. In places where it was possible, the original building fabric was brought to the fore. This is particularly evident in the exposed roof truss, which is over 600 years old, the exposed beams on the ground floor as well as the load-bearing beams or the partially exposed natural stone façade in the interior.
Lessons learned
“We had everything done by local craftsmen. Because we had to let it work in small steps and the preservation of monuments made high demands. So the craftsmen had to come again and again for a few days or hours and that was only possible for short distances”. ( Monika Fritsch, client)
Stakeholders Involvement
Private Sector
Monika und Thomas Fritsch
Kreichwichstr. 2, 92342 Freystadt
Architect
Stefan Lerzer
Rennbahnstr. 1, 92318 Neumarkt i. d. Opf.
info@lerzer-ip.de
Tel.09181 - 270 590
Energy Consultant
Thomas Brandl
Alfred-Bischoff-Str. 8, 92318 Neumarkt i. d. Opf.
info@energieberater- brandl.de
Tel.09181 - 899 822
Tools used
Was the renovation process done following a specific methodology? No
Energy calculation Energieberater 18599 3D PLUS 9.0.5 - Hottgenroth Software -
Hygrothermal assessment in Klärung
Life Cycle Analysis (LCA) Alle wesentlichen Bauphasen wurden durch Bohrkerne dendrochronologisch bestimmt.
Other Des Weiteren wurde ein verformungsgerechtes Bauaufmaß erstellt.

RETROFIT SOLUTIONS

External Walls

Wall outside air east

Wall outside air nord

Wall outside air south

Wall outside air west

Wall outside air west

Wall outside air east

The existing 300 cm thick sandstone masonry could be preserved. Most of the existing plaster was no longer present. The wall area is 44. 18 m².

The existing wall was insulated on the outside with a thermal insulation composite system as an energy-saving measure. In the inside a plaster mortar of lime gypsum, gypsum, anhydrite and lime anhydrite was applied.

U-value (pre-intervention) [W/m2K]: 3,211 W/m²K U-value (post-intervention) [W/m2K]: 0,19 W/m²K
More Details
Original wall build-up
Render - Bestandsputz:
10 mm
Stone - Bestehendes Mauerwerk U=1,70 W/m²K:
300 mm
Retrofitted wall build-up
Render - Putzmörtel aus Kalkgips, Gips, Anhydrit und Kalkanhydrit:
15mm
Stone - Bestehendes Mauerwerk U=1,70 W/m²K:
300 mm
Render - Putzmörtel aus Kalk, Kalkzement und hydraulischem Kalk:
15 mm
Insulation - Wärmedämmverbundsystem (WLG 035):
160 mm
Render - Klebemörtel, Klebespachtel:
10 mm
Wall outside air nord

The existing 250 cm thick brick masonry (klinker) could be preserved. The existing plaster was mostly no longer available. The wall area is 26. 57 m².

The existing masonry was insulated with a composite thermal insulation system as an energy-saving measure both on the outside and on the inside. In the interior, a plaster mortar of lime gypsum, gypsum, anhydrite and lime anhydrite was applied.

U-value (pre-intervention) [W/m2K]: 2,265 W/m²K U-value (post-intervention) [W/m2K]: 0,13 W/m²K
More Details
Original wall build-up
Render - Lehmputz:
10 mm
Brick - Ziegelsteinwand:
250 mm
Retrofitted wall build-up
Render - Klebemörtel, Klebespachtel:
10mm
Insulation - Wärmedämmverbundsystem (WLG 035):
120 mm
Brick - Ziegelsteinwand:
240 mm
Render - Putzmörtel aus Kalk, Kalkzement und hydraulischem Kalk:
15 mm
Insulation - Wärmedämmverbundsystem (WLG 035):
120 mm
Render - Klebemörtel, Klebespachtel:
10 mm
Wall outside air south

The existing 240 cm thick sandstone masonry could be preserved. Most of the existing plaster was no longer present. . The wall area is 42. 87 m².

The existing wall could be preserved. Most of the existing plaster was no longer present. The existing wall was insulated on the outside with a thermal insulation composite system as an energy-saving measure. The existing wall of the south facade was not plastered in the interior and is therefore visible.

U-value (pre-intervention) [W/m2K]: 3,505 W/m²K U-value (post-intervention) [W/m2K]: 0,21 W/m²K
More Details
Original wall build-up
Render - Bestandsputz:
10 mm
Stone - Bestehendes Mauerwerk U=1,70 W/m²K:
240 mm
Retrofitted wall build-up
Stone - Bestehendes Mauerwerk U=1,70 W/m²K:
240mm
Render - Putzmörtel aus Kalk, Kalkzement und hydraulischem Kalk:
15 mm
Other - 12,9%: Konstruktionsholz (DIN 12524 - 500 kg/m³), 87,1%: Zellulosedämmung:
160 mm
Other - Putzträgerplatte, Holzfaserplatte:
50 mm
Render - Klebemörtel, Klebespachtel:
10 mm
Wall outside air west

The existing 240 cm thick sandstone masonry could be preserved. Most of the existing plaster was no longer present. The wall area is 34. 91 m².

The existing wall could be preserved. Most of the existing plaster was no longer present. The existing wall was insulated on the outside with a thermal insulation composite system as an energy-saving measure. In the inside a plaster mortar of lime gypsum, gypsum, anhydrite and lime anhydrite was applied.

U-value (pre-intervention) [W/m2K]: 3,505 W/m²K U-value (post-intervention) [W/m2K]: 0,18 W/m²K
More Details
Original wall build-up
Render - Bestandsputz:
10 mm
Stone - Bestehendes Mauerwerk U=1,70 W/m²K:
240 mm
Retrofitted wall build-up
Render - Putzmörtel aus Kalkgips, Gips, Anhydrit und Kalkanhydrit:
15mm
Stone - Bestehendes Mauerwerk U=1,70 W/m²K:
240 mm
Render - Putzmörtel aus Kalk, Kalkzement und hydraulischem Kalk:
15 mm
Other - 13,3%: Konstruktionsholz (DIN 12524 - 500 kg/m³), 86,7%: Zellulosedämmung:
15 mm
Other - Putzträgerplatte, Holzfaserplatte:
50 mm
Insulation - Schilfrohr Dämmplatten:
50 mm
Render - Putzmörtel aus Kalk, Kalkzement und hydraulischem Kalk:
15 mm
Wall outside air west

The existing 240 cm thick sandstone masonry could be preserved. The existing plaster was mostly no longer available. The wall area is 4. 98 m².

The existing wall could be preserved. Most of the existing plaster was no longer present. The existing wall was insulated on the outside with a thermal insulation composite system as an energy-saving measure. In the inside a plaster mortar of lime gypsum, gypsum, anhydrite and lime anhydrite was applied.

U-value (pre-intervention) [W/m2K]: 3,505 W/m²K U-value (post-intervention) [W/m2K]: 0,19 W/m²K
More Details
Original wall build-up
Render - Bestandsputz:
10 mm
Stone - Bestehendes Mauerwerk U=1,70 W/m²K:
240 mm
Retrofitted wall build-up
Render - Putzmörtel aus Kalkgips, Gips, Anhydrit und Kalkanhydrit:
15mm
Stone - Bestehendes Mauerwerk U=1,70 W/m²K:
240 mm
Insulation - Wärmedämmverbundsystem (WLG 035):
160 mm
Render - Klebemörtel, Klebespachtel:
10 mm


Windows

Window

flat roof windows

Window

The existing wooden windows were replaced by old and new windows with similar forged fittings. The documents show that box windows were installed on the ground floor. By installing a 2-panel thermal insulation glazing, the existing building was energized.

Due to the identical windows with identical wrought iron fittings, the appearance of the existing windows could be preserved as far as possible.

Existing window U-value Glass [W/m2K]: 0,0 New window U-value Glass[W/m2K]: 0,6 Existing window U-value Frame [W/m2K]: 0,0 New window U-value Frame [W/m2K]: 1,3
More Details
Existing window type Fixed window
Existing glazing type Single
Existing shading type NA
Approximate installation year 1886
New window type Box-type window
New glazing type Double
New shading type Outer shutter
New window solar factor g [-] 0,6
flat roof windows

Installation of a DFF 2-panel heat insulation glazing with plastic frame and a stainless steel edge compound. The gable walls have a thermal resistance value of 0.26 W/m2 K. The structure of these gable walls consists of 6cm wood fibreboard WLG 045, a board formwork, 10cm insulation WLG 032 between the beams and a steam brake.

There were no roof windows in the existing building. The roof windows were provided with the same historical window frame as the other windows in the farmer’s house.

New window U-value Glass[W/m2K]: 1,0 New window U-value Frame [W/m2K]: 1,35
More Details
Existing window type no existing window
Existing glazing type no existing window
Existing shading type NA
New window type flat roof windows
New glazing type Double
New shading type NA
New window solar factor g [-] 0,6

Other interventions

ROOF

GROUND FLOOR

OTHER

ROOF

The oldest roof structure of the district should be preserved as far as possible. In order to remove the soot of the last centuries, the owners Thomas and Monika Fritsch brushed the old beams for weeks in the course of the renovation. Parts of the roof structure that could no longer be saved were replaced by new ones.

The oak beams of the roof come from trees that were felled between 1396 and 1408.

U-value (pre-intervention) [W/m2K] 3,704 U-value (post-intervention) [W/m2K] 0,22
More Details
Original roof build-up
Tiles - Biberschwanzziegel :
25 mm
Other - Lattung (Konterlattung) :
50 mm
Retrofitted roof build-up
Tiles - Biberschwanzziegel :
25 mm
Other - Konstruktionsholz (DIN 12524 - 500kg/m3):
27 mm
Other - Dampfbremse:
2 mm
Other - 14,3%: Konstruktionsholz (DIN 12524 - 500kg/m3), 85,7%: Zellulosedämmung:
160 mm
Other - Diffusionsoffene Unterdeckplatten:
52 mm
Other - Sparren 19/16:
190 mm
GROUND FLOOR

In the course of the renovation a new floor structure was built on all floors. The floor slab against the ground was adequately insulated both from below and from above. The ceiling against the unheated basement was insulated from above. Underfloor heating has been installed in all rooms for a comfortable room temperature and foot warmth.

There was no usable floor structure in the existing building.

U-value (post-intervention) [W/m2K] 0,21
More Details
Original groundfloor build-up
Finish - Holzdielen (Annahme):
50 mm
Other - Unterkonstruktion Holz mit Zwischendämmung (Annahme):
100 mm
Retrofitted groundfloor build-up
Finish - Holzdielen :
14 mm
Other - Asphalt (DIN 12524) mit Fußbodenheizung:
40 mm
Insulation - Dämmung unter Estrich:
60 mm
Other - nackte Bitumenbahn (DIN 52129):
5 mm
Concrete slab - Beton armiert mit 1% Stahl (DIN 12524), (neue Bodenplatte):
150 mm
Insulation - TECHNOpor Glasschaum-Granulat (Dämmung unter Bodenplatte):
250 mm
OTHER

A terrace was built in the west on the roof of the narrow annex. In addition, the no longer existing front garden with wall was reconstructed.

The existing building already had a small half-height intermediate building with a flat roof to the west. This was taken up in the course of the renovation, energetically upgraded and thus extends the usable space on the ground floor. A terrace with a filigree railing was built on the flat roof. By reconstructing the front garden with the wall made of sandstone, a part of the former building was restored.

HVAC

HEATING

VENTILATION

DOMESTIC HOT WATER

HEATING

While most of the neighbour buildings had already been equipped with modern heating systems, the previous occupant, Mrs Fischbacher, was still living in her almost 600-year-old cottage with a charcoal stove for heat. The charcoal stove was replaced by a central heat generation system. The new gas condensing boiler has a buffer tank for domestic hot water storage, hydraulic balancing (KfW confirmation) and insulated pipes in accordance with EnEV. This gas condensing boiler also heats the underfloor heating installed in all rooms. This has an average temperature of 35/28°C. As an additional heating source, a fireplace stove was connected in the ground floor living room. This also creates a pleasant homely atmosphere.

The farmhouse has only a decentralized coal-fired furnace for heat generation. This was replaced by a central gas-combustible heating system, underfloor heating throughout the building and a fireplace stove.

More Details
New primary heating system New secondary heating system
New system type Condensing Stove
Fuel Gas Biomass
Distribuition system Radiating floor Air
Nominal power 14,2 kW NA kW
VENTILATION

A central ventilation system with exhaust air/feed air heat transfer (heat recovery) was installed for a pleasant room atmosphere. The heat supply ratio is 40%.

There was no ventilation system in the existing building. A new system was installed.

More Details
Original roof build-up New ventilation system
Type ventilation system Decentralized
Type flow regime
Heat recovery Yes
Humitidy recovery No
Nominal power 0,30 kW
Electric power 0,0 kW
Control system Einzelraumregelung
DOMESTIC HOT WATER

Prior to the renovation, there was no means of producing hot water, except for the charcoal stove. The new central system has also created a possibility for hot water preparation as well as hot water storage. The gas condensing boiler has a buffer tank for storing domestic hot water.

The existing building did not have any means of generating hot water or storing hot water. Only the old charcoal stove could be heated portions of water. As a result, a completely new system was installed.

More Details
New DHW system
Type with heating system
Hot_water_tank Yes
With heat recovery No

Energy Efficiency

Energy Performance
Energy performance certificate: There is an energy certificate for residential buildings in accordance with §§ 16 ff. Energy Saving Ordinance (EnEV) of 18. November 2013. The final energy demand of this building is 73. 4 kWh (m²a) and the primary energy demand is 85. 1 kWh (m²a). The procedure according to DIN V 4108-6 and DIN V 4701-10 was used to calculate the energy demand. The energy quality of the building envelope has an actual value of 0. 36 W/(m²K). The CO² emissions amount to 19. 2 kg(m²a).
Voluntary certificates: No
Energy Use
Heating
Primary Energy 85,1 kWh/m2.y
Documents:
Ergebnisse Heizung.jpg
Energie consultant and planning office Thomas Brandl: Results heating
Energieausweis Seite 1.jpg
Energieberatungs- und Planungsbüro Thomas Brandl: Energy certificate page 1
Energieausweis Seite 3.jpg
Energieberatungs- und Planungsbüro Thomas Brandl: Energy certificate page 3
Energieausweis Seite 2.jpg
Energieberatungs- und Planungsbüro Thomas Brandl: Energy certificate page 2
Energieausweis Seite 4.jpg
Energieberatungs- und Planungsbüro Thomas Brandl: Energy certificate page 4
Energieausweis Seite 5_1.jpg
Consumption_estimation_After: 61,94 kWh/m2.y

Primary Energy
Consumption_estimation_Calculation_method: Derived from energy bills
Documents:
Primärenergie.jpg
Energie consultant and planning office Thomas Brandl: Primary energy

Consumption_estimation_Including_DHW: Yes
Consumption_estimation_After: 85,1 kWh/m2.y

Internal Climate

Temperature

Normal indoor temperature

Indoor Air Quality

Thanks to the newly installed ventilation system the interior has a consistently good indoor climate.

Daylight

Due to the numerous existing windows as well as the newly installed roof-gapes, the living rooms have enough natural light. If necessary, the interior spaces can be shaded by the shutters out of wood.

Acoustic Comfort

There are pleasant room and building acoustics.

Artifact Conservation

There is no artifact.

Costs

Financial Aspects

An important aspect is energy saving. Costs are saved by reed insulation, ventilation and the condensing boiler. The exact amount is not known. During construction, efforts were also made to reduce costs. Due to the high demands of the monument protection it was possible to work only in small steps. Therefore, all trades were assigned to local craftsmen. Thus, the craftsmen did not have to charge long distances to get there, if they worked every now and then for a few days or hours.

Investment Costs
Total investment costs
2.648 € (per m2)
In order to give you a better service this site uses cookies. Additionally third party cookies are used. By continuing to browse the site you are agreeing to our use of cookies. More information