GENERAL INFORMATION RENOVATION PROCESS RETROFIT SOLUTIONS EVALUATION

Casa Rossa Chemnitz

Gießerstraße 41

09130

Chemnitz, Germany

Architect

bodensteiner fest Architekten BDA, Stadtplaner PartGmbB

Ickstattstraße 9 Rgb, D 80469 München

mail@bodensteiner-fest.de

49 (0)89 89223388

Contact Details

Christian Bodensteiner

bodensteiner fest Architekten BDA

mail@bodensteiner-fest.de

49 89 89223388

Other Information

Visits
upon request

Related publications
https://www.bodensteiner-fest.de/projekte/2019/GIE-casa-rossa-chemnitz.php

The multi-family house from the turn of the century was saved from demolition and extensively renovated. 6 apartments were set up with the latest technology and low energy consumption. The usable building fabric was carefully renovated and new elements added accordingly.

GENERAL INFORMATION RENOVATION PROCESS RETROFIT SOLUTIONS EVALUATION

Energy performance

55,3 kWh/m2.y

Climate Zone Cfb

Altitude 298 m a.s.l.

HDD 3486

CDD 150

Protection level Not listed

Conservation Area:
Yes

Level of Protection:
Building is not protected

Building age 1900-1944

Year of last renovation:
2018

Building use Residential (urban)

Building occupancy:
Permanently occupied

Building area Net floor area [m²]: 578,0

Building typology:
Tenement (apartments)

Number of floors:
5

Basement yes/no:
Yes

Number of heated floors:
5

NFA calculation method:
NGF (de)

Construction type

Brick masonry wall

External finish:
Exposed brickwork

Internal finish:
Exposed brickwork

Roof type:
Pitched roof

+ MORE - LESS

RENOVATION PROCESS

Architecture

BUILDING DESCRIPTION

The comprehensive renovation enables comfort standards from the new building in the guise of an old building: This creates spacious units of 46 to 168 square meters, original ceiling heights of 3 meters and room sizes of up to 55 square meters. New solid ceilings offer good sound insulation like in a new building. The oiled oak parquet is glued over the entire surface, so it doesn't clack. The south orientation lets a lot of sun into the living rooms. All apartments have a terrace, a balcony and / or a roof terrace. MINIMALIST ARCHITECTURE The really special thing about this house is the space that was given to the architectural concept - the modern interpretation of the charm of the old building in a minimalist design language. Old and new form a special connection with this Wilhelminian style jewelery. The apartments are planned down to the smallest detail and have a high-quality bathroom design with state-of-the-art equipment. Underfloor heating ensures a high level of living comfort, the solar thermal system on the roof ensures low heating and hot water costs. The energy consumption values are at the level of a new building. The materials were selected according to ecological and building biology aspects: wooden windows / brick ceilings / mineral insulation or cellulose insulation / smooth lime plaster, etc. The very narrow window sashes of the street facade, framed by accurate frames, contrast with the rough brick facade with all its irregularities and the visible wounds from the last century. The carefully exposed, brightly glazed brick masonry not only characterizes the street facade. The bricks also spread the special flair of the imperfect in the stairwell and in the apartments.

Urban context

Casa Rossa Chemnitz is located in the Sonnenberg area monument. Where fields had stretched until then, between 1850 and 1914, due to the increasing demand for housing in the course of industrialization, areas with long streets were planned and residential blocks were built, starting on the south-sunny side along Augustusburger Straße. At the beginning of the 20th century, the quarters of the decidedly workers' residential area were extremely densely occupied. The Wilhelminian-style districts were declared area monuments after the fall of the Wall.

State of repair

Conditions of the envelope

The house was initially propped up from the basement to the roof and secured. After the house had been cleared and all components that could come loose in the event of vibrations had been removed or reattached, the ceiling replacement could begin. Only after the dilapidated wooden beam ceilings had been replaced in a chessboard-like manner with new brick-clad ceilings and the roof structure had been replaced, the actual renovation could begin.

Description of pre-intervention building services

No building services available. The entire building technology was renewed

HERITAGE SIGNIFICANCE

ELEMENTS WORTHY OF PRESERVATION

The street facade as a characteristic brick facade was preserved and refurbished in its appearance. The staircase with the old railings was preserved, as was the interior doors and facade friezes that can still be used

Heritage Value Assesment

The building is not on the list of monuments. But it blends in harmoniously with the street scene. There are many listed monuments in the same street, most of them in good condition - thanks to good funding. This building is an example of how, in a very difficult environment for investors, buildings can be preserved economically even without monument subsidies. The building was honored with an award and a special sustainability prize: https://www.heinze.de/architekturobjekte/architektenaward/rueckblick/2020/

Aim of retrofit

Renovation

Due to the dilapidated condition of the building, it was initially necessary to restore the stability and secure the building fabric. The old wooden ceilings were replaced in a chessboard-like manner with brick hanging ceilings, the roof was secured against collapse. In the course of the ceiling replacement, the previous toilets, accessible from the landing in the stairwell, were assigned to the bathrooms of the apartments and their ceilings were raised to the level of the apartments. In contrast to the minimalist new elements, the brick walls of the stairwell and the walls of selected areas in the apartments were carefully stripped of plaster, supplemented with recycled original bricks and glazed with light. The same principle also determines the appearance of the facade: Accurate brackets hide the window frames and hold the narrow window sashes. They stand in contrast to the rough brick facade with all its irregularities and the visible wounds of the last century. The tectonics of the facade were further worked out: concrete lintels, cornices and steel girders were restored, the brickwork with cofferings and pilaster strips was re-grouted and coated with a light mineral glaze and made hydrophobic. In a respectful treatment of the building fabric, the building was "Continued to build".

Lessons learned

An economical and careful renovation of the building could be carried out through integral planning with all the engineers involved. Intensive construction supervision for quality assurance is necessary.

Stakeholders Involvement

Architect
bodensteiner fest Architekten BDA, Stadtplaner PartGmbB
Ickstattstraße 9 Rgb, D 80469 München
mail@bodensteiner-fest.de
Tel. 49 (0)89 89223388

Tools used

Was the renovation process done following a specific methodology? For the preservation of the existing building and for security measures, reports on building protection and mold growth were drawn up

Energy calculation Hottgenroth Energieberater 18599
Hygrothermal assessment Thermal bridge calculations for individual components
Life Cycle Analysis (LCA) No LCA tool applied
Other Die ursprünglich verputzte Fassade wurde als sichtbare Ziegelfassade ertüchtigt und prägt das Erscheinungsbild

RETROFIT SOLUTIONS

External Walls

Street facade unplastered

Backyard facade with cladding

Street facade unplastered

The tectonics of the facade were further worked out: concrete lintels, cornices and steel girders were restored, reveals were insulated, the brickwork with cassettes and pilaster strips was re-grouted and coated with a light mineral glaze and made hydrophobic. The joints of the facades have been refurbished and the facade has been hydrophobized with a 20-year warranty and is maintained like a facade painting.

Window formats have been kept, the outside trims have been articulated. The view of the street side was not changed. On the garden side, balconies were added

U-value (pre-intervention) [W/m2K]: 0,85 W/m²K U-value (post-intervention) [W/m2K]: 0,85 W/m²K

More Details

Original wall build-up

Other :
2 mm

Brick :
300 mm

Cladding :
30 mm

Retrofitted wall build-up

Other - waterproof paint:
2mm

Brick :
300 mm

Cladding :
30 mm

Backyard facade with cladding

The rear courtyard facade was made with 12cm mineral WD as ETICS with 15mm thick plaster

The rear courtyard facade was largely retained in terms of design, door openings for balconies were necessary to increase living quality, the balconies were placed in front of them as a light steel construction

U-value (pre-intervention) [W/m2K]: 0,85 W/m²K U-value (post-intervention) [W/m2K]: 0,2 W/m²K

More Details

Original wall build-up

Cladding :
30 mm

Brick :
300 mm

Cladding :
30 mm

Retrofitted wall build-up

Cladding :
15mm

Insulation :
120 mm

Brick :
300 mm

Cladding :
30 mm

Windows

Wooden window with insulated window frame, visible from the inside

Accurate bezels hide the window frames and hold the narrow window sashes. They stand in contrast to the rough brick facade with all its irregularities and the visible wounds of the last century. The tectonics of the facade was further worked out: concrete falls, Cornices and steel girders were restored, the brickwork with cofferings and pilaster strips was re-grouted and coated with a light mineral glaze and made hydrophobic.

The windows were exchanged and replaced with new windows. The wall connection was made with adapted insulation frames

bodensteiner fest Architekten BDA

Existing window U-value Glass [W/m2K]: 6,0 New window U-value Glass[W/m2K]: 0,6 Existing window U-value Frame [W/m2K]: 2,0 New window U-value Frame [W/m2K]: 0,95

More Details

Existing window type	Casement window
Existing glazing type	Single
Existing shading type	NA
Approximate installation year	1910

New window type	Casement window
New glazing type	Triple
New shading type	NA
New window solar factor g [-]	0,55

Other interventions

ROOF

OTHER

MEASURES TO INCREASE AIRTIGHTNESS

ROOF

The roof was completely demolished and rebuilt using demolition bricks. By opening the roof side on the courtyard side, additional living space is created, which is oriented towards a spacious roof terrace with sliding doors.

The roof view of the street side was changed minimally, the flat built-in parts in the roof were adapted in color to the roof covering. Roof terraces were integrated on the garden side, these are not visible from the garden.

U-value (pre-intervention) [W/m2K] 5 U-value (post-intervention) [W/m2K] 0.12

More Details

Original roof build-up

Tiles - Shingles:
20 mm

Other - Roof Boarding:
24 mm

Other - Rafters:
140 mm

Other - NN:
5 mm

Retrofitted roof build-up

Shingles - Shingles:
20 mm

Other - Roof Boarding:
24 mm

Other - Rafters / cellulose injection insulation:
280 mm

Other - Wood/ Plasterboard:
24 mm

OTHER

The floor to the cellar, a cap ceiling, was insulated with perlite fill (on average approx 8cm, on top of it insulation of the underfloor heating 4cm)

The insulation was invisibly applied to the existing cap ceiling and does not impair the visual appearance

MEASURES TO INCREASE AIRTIGHTNESS

All windows were connected to be wind and rainproof. The building envelope and the roof were made windproof, a blower door test was carried out

Airtightness (pre-intervention) [ach@50Pa] 4 Airtightness (post-intervention) [ach@50Pa] 1.4

HVAC

HEATING

VENTILATION

DOMESTIC HOT WATER

HEATING

A completely new heating system was installed. A solar system supplies floor heating and domestic hot water. Many close-meshed heating circuits have been laid to optimize solar use for low-temperature heating.

The existing shafts were largely used. The heating was designed as underfloor heating because the floors had to be completely renewed. Cables were partially laid on the plaster.

More Details

	New primary heating system	New secondary heating system
New system type	Condensing
Fuel	Gas	Solar
Distribuition system	Radiating floor	Radiating floor
Nominal power	18 kW	kW

VENTILATION

Exhaust system for internal bathrooms with overflow opening, fresh air supply via window rebate ventilation

Exhaust air is moved into shafts

More Details

Original roof build-up	New ventilation system
Type ventilation system	Decentralized
Type flow regime	Overflow
Heat recovery	No
Humitidy recovery	No
Nominal power	0.015 kW
Electric power	0,015 kW
Control system	light and CO2 sensor

DOMESTIC HOT WATER

Solar thermal system for domestic hot water and heating support. Heating system with gas boiler

Thermal solar collectors match the color of the roof

More Details

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

RENEWABLE ENERGY SYSTEMS

SolarThermal

Solar thermal collectors

The color was adapted to the roof skin. A roof-top system was chosen to enable simple reversibility of the technical component as soon as there are fully compatible components in terms of design, which is often a requirement for monument protection. Together with the roof windows, they represent a neglibible disturbance of the roof landscape. The installation of components for the generation of renewable energies are often privileged compared to the preservation of monuments. So far there are no adequate components in terms of color and haptics.

More Details

	SolarThermal System
Type	Flat collector
Collector area	20,0 m²
Elevation angle	30,0
Overall yearly production	12000,0 kWh
Heating_contribuition	2000,0 kWh
DHW contribuition	10000,0 kWh
Cooling contribuition	0,0 kWh

Energy Efficiency

Energy Performance

Energy performance certificate: KfW 100 Standard/ reference building 91 kWh/m2.y
Voluntary certificates: No

Energy Use

Heating
Primary Energy 62,8 kWh/m2.y

Documents:

Energieausweis.pdf
Consumption_estimation_After: 55,3 kWh/m2.y

Primary Energy
Consumption_estimation_Calculation_method: NA
Consumption_estimation_Including_DHW: Yes
Consumption_estimation_After: 62,8 kWh/m2.y

Measured Parameters

Internal Climate
Type_of_monitoring: Punctual
Description: Annual billing of energy consumption

Internal Climate

Temperature

The building envelope was made airtight with new, highly efficient windows. The roof was provided with maximum insulation thickness. There was positive feedback on comfort from users

Indoor Air Quality

In summer, the building mass and the cellulose roof insulation ensures an appropriate temperature level. In winter, the underfloor heating offers radiant heat at the highest level of comfort

Daylight

The existing window sizes have not been changed, they offer adequate lighting comfort. The attic apartment was provided with roof windows and large terrace windows for the best lighting conditions.

Acoustic Comfort

The floors have been upgraded according to the acoustic standards. All HVAC istallations comply with acoustic norms

Costs

Financial Aspects

The renovation standard was adapted to the state of the art and comfort. A market analysis showed an economic viability for the chosen renovation strategy

Running Costs

Lifecycle cost
No