3601487
2025-02-23 16:58:56
- #1
Good day everyone,
after months of planning our renovation project and some research also in this forum (thanks for all the tips!), I would like to ask you for a brief assessment of our cost planning. First of all: Sorry for the level of detail, I am someone who likes to plan in a structured and extensive way. I don’t expect from you (actually nothing at all, since you do this for fun and free of charge) to read through all the details but just a few ideas / assessments on certain points and a rough confirmation or objections. Many thanks in advance for that!
A brief introduction about me: I am 37 years old and trained as an electrician (15 years ago). So I know construction sites reasonably well from the inside, have helped on a few sites in the meantime and can estimate some things (especially technology like heating and electrical) quite well. What I cannot estimate at all is everything related to building components, concrete, or masonry...
Basic information about the house:
On the plot there is a building constructed in 1960 in solid construction with a gable roof and two dormers. The footprint of the house is approx. 8.45 x 7.95 m and there is a balcony extension on the garden side. The house is on a slope; towards the garden (i.e., south direction) the basement floor is fully visible, towards the street the basement floor is completely covered.
The water supply is provided via a private well on the property. Wastewater disposal is via a pressure drainage system, whose shaft is on the plot. From there, the wastewater is pumped into a higher-level collection point of the sewer system. Drainage of roof and sealed surfaces is carried out via an infiltration system on the property that directs excess water into the small stream at the lower end of the property.
The plot is located in a rural area outside the central area of a medium-sized town in NRW. No development plan exists, construction ban in the outer area, so the building must remain as it is (at least on the outside). Otherwise, I would have preferred to demolish and rebuild. The view and the peace make up for a lot.
Building fabric:
The floor slab in the basement consists of unreinforced rammed concrete and is about 8 cm thick. Directly beneath the slab is soil made of loamy ground. The structure was determined by core drilling, still it might be that the concrete is reinforced.
The exterior walls are designed as double-shell masonry. The air layer between the masonry was retrofitted with blown-in insulation of mineral material. The thickness of the air layer varies between 4 and 8 cm. Different types of bricks were used as wall material. Mainly hollow bricks were installed.
The basement ceiling is constructed as a steel beam capped ceiling with hollow brick masonry. The ground and upper floor ceilings are timber beam ceilings.
The basement staircase is made of concrete. Large ceramic tiles are used as stair treads. The upper floor staircase is made of wood and has two landings. The attic staircase is accessed via an attic hatch with a pull-out ladder from the upper floor hallway.
The roof is a gable roof with purlin construction with a pitch of about 52°. On the left and right house sides there is a roof overhang of approx. 15 cm, on the building sides facing the street and garden there is a roof overhang of 25 cm. The roof was newly covered in the late 1980s with gray clay tiles. During that time, the dormer on the street side was built. The dormer to the garden side was already part of the house when the building was erected. In 2003, the attic was insulated with mineral wool mats and a vapor barrier was glued. The house has two chimneys on the gable roof. The first chimney is no longer in use, the second chimney serves the currently installed oil heating system.
The house has its own water supply via a well system on the property. Wastewater is disposed of via a pressure pipeline leading from the collection shaft on the site to the higher-lying municipal sewer system. The house connections for water and sewage are on the east side in the basement; there is also the pumping station including water tank. An oil heating system was installed in 2003, which heats the rooms via radiators and provides central hot water preparation. The oil heating system itself is located in the basement, where the oil tank is also housed. The electrical installation is moderately modern, the meter cabinet including main distribution is located in the basement hallway. The house connection box is mounted on the northeast side of the house, where the supply line from the utility company also enters. The routing of the telecommunications system (copper cables) is still unclear at the present time.
An existing energy certificate has already been created (building category H). The demolition work by ourselves is already well advanced, all wall and floor coverings have been removed, all ceiling claddings have been dismantled and ceilings exposed. The building seems to have no major defects (no wet basement walls, no flakings or cracks, no mold).
Basic information about the renovation project:
The project concerns a complete renovation of an existing single-family house. The building will be completely gutted and brought to the KfW55 EE standard. In addition, extensive interior finishing measures will be carried out as well as the construction of a new balcony, a carport, and a canopy for the front door. The largest subprojects in the renovation are:
In addition, a variety of smaller and larger adjustments will be made inside the house:
An architect, a structural engineer, and an energy consultant are already on board and have confirmed many of my plans and provided information. Currently, the architect is working on the approval planning which should be finished in about one week. The energy consultant will then create the BZA for funding and we will proceed with financing talks. For that I now need your help or assessment. We will commission the work on our own after approval; some offers (e.g. windows, underpinning of strip foundations, perimeter insulation) are already available to me and approximately fit the following calculation. The remaining offers will arrive gradually and will be prepared based on a detailed scope of work / construction description created by me.
I know such a renovation project has its peculiarities and is difficult to assess. Our advantage is that a knowledgeable construction manager friend lives next door and will support us a lot. I have now completed the entire construction description, hence also the detailed description here. Basically, a lot will be done in self-performance; I have some time available and a few good colleagues who will help. Everything involving statics, watertightness, and other difficult or dangerous work will, of course, be performed by specialist companies. The electrical installation done in self-performance will be later inspected by the specialist company from which I will source the materials.
Overview of the current building cost estimate:
The following construction costs I have gathered from extensive research from various sources (architect, craftsmen known to me) and then roughly averaged. In the presentation, I tried to follow DIN 276 (slightly customized to my needs, please forgive me if it doesn’t fully comply with the standard). All costs are shown as gross costs.
Explanation of columns:
Cost group Preparation and Demolition (Please note: very much self-performance!):
-----
Cost group Foundations:
-----
Cost group Exterior walls:
-----
Cost group Interior walls:
-----
Cost group Ceilings / Floor coverings:
-----
Cost group Roof:
The new roof area will be considerably smaller due to the changed dormer pitch; therefore, only 89 m² of roof will be re-covered and insulated.
-----
Cost group Water supply and wastewater disposal, sanitary:
-----
Cost group Heat supply:
-----
Cost group Ventilation systems:
-----
Cost group Electrical installation (Please note: all will be done by ourselves with a few colleagues, we are all electricians. So here only material costs are meant. Overall it shall represent a very high-end equipment level):
-----
Cost group Traffic areas:
-----
Cost group Fencing:
-----
Cost group Outdoor facilities:
-----
Cost group Planning costs:
-----
Cost group Approval:
-----
Cost group Construction-related additional costs:
In total, this amounts to approximately €540,000 including all the above listed cost items and the already incurred disposal costs. The earthworks are quite detailed but are already included in several positions. Here we also have access to a mini-excavator and a landscaper who will do it at a reasonable price. Due to the large plot, much of the soil can be reused in the garden for lawn base layers.
The execution planning is carried out by the architect on an hourly basis where necessary (everything regarding statics and watertightness). The rest shall be planned by the trades or by ourselves. The construction management (and coordination of the execution planning) is done by the neighbor, who we are good friends with and who professionally works as a construction manager.
The house already belongs to us and is thus part of the equity. The house will later have (including creditable balcony areas) a living and usable area of 156 m², resulting in about €3,400 / m² construction costs.
What is your assessment of the planned works? Does it roughly fit or am I significantly below / above your cost estimates in one area or another? Attached you will find the current drafts, which still have some detailing work. Afterwards, it will go into approval, whose preliminary inquiry has already been positively decided.
Thank you very much for reading and (if you like) answering. I am grateful for every tip and look forward to your questions.
Best regards!
after months of planning our renovation project and some research also in this forum (thanks for all the tips!), I would like to ask you for a brief assessment of our cost planning. First of all: Sorry for the level of detail, I am someone who likes to plan in a structured and extensive way. I don’t expect from you (actually nothing at all, since you do this for fun and free of charge) to read through all the details but just a few ideas / assessments on certain points and a rough confirmation or objections. Many thanks in advance for that!
A brief introduction about me: I am 37 years old and trained as an electrician (15 years ago). So I know construction sites reasonably well from the inside, have helped on a few sites in the meantime and can estimate some things (especially technology like heating and electrical) quite well. What I cannot estimate at all is everything related to building components, concrete, or masonry...
Basic information about the house:
On the plot there is a building constructed in 1960 in solid construction with a gable roof and two dormers. The footprint of the house is approx. 8.45 x 7.95 m and there is a balcony extension on the garden side. The house is on a slope; towards the garden (i.e., south direction) the basement floor is fully visible, towards the street the basement floor is completely covered.
The water supply is provided via a private well on the property. Wastewater disposal is via a pressure drainage system, whose shaft is on the plot. From there, the wastewater is pumped into a higher-level collection point of the sewer system. Drainage of roof and sealed surfaces is carried out via an infiltration system on the property that directs excess water into the small stream at the lower end of the property.
The plot is located in a rural area outside the central area of a medium-sized town in NRW. No development plan exists, construction ban in the outer area, so the building must remain as it is (at least on the outside). Otherwise, I would have preferred to demolish and rebuild. The view and the peace make up for a lot.
Building fabric:
The floor slab in the basement consists of unreinforced rammed concrete and is about 8 cm thick. Directly beneath the slab is soil made of loamy ground. The structure was determined by core drilling, still it might be that the concrete is reinforced.
The exterior walls are designed as double-shell masonry. The air layer between the masonry was retrofitted with blown-in insulation of mineral material. The thickness of the air layer varies between 4 and 8 cm. Different types of bricks were used as wall material. Mainly hollow bricks were installed.
The basement ceiling is constructed as a steel beam capped ceiling with hollow brick masonry. The ground and upper floor ceilings are timber beam ceilings.
The basement staircase is made of concrete. Large ceramic tiles are used as stair treads. The upper floor staircase is made of wood and has two landings. The attic staircase is accessed via an attic hatch with a pull-out ladder from the upper floor hallway.
The roof is a gable roof with purlin construction with a pitch of about 52°. On the left and right house sides there is a roof overhang of approx. 15 cm, on the building sides facing the street and garden there is a roof overhang of 25 cm. The roof was newly covered in the late 1980s with gray clay tiles. During that time, the dormer on the street side was built. The dormer to the garden side was already part of the house when the building was erected. In 2003, the attic was insulated with mineral wool mats and a vapor barrier was glued. The house has two chimneys on the gable roof. The first chimney is no longer in use, the second chimney serves the currently installed oil heating system.
The house has its own water supply via a well system on the property. Wastewater is disposed of via a pressure pipeline leading from the collection shaft on the site to the higher-lying municipal sewer system. The house connections for water and sewage are on the east side in the basement; there is also the pumping station including water tank. An oil heating system was installed in 2003, which heats the rooms via radiators and provides central hot water preparation. The oil heating system itself is located in the basement, where the oil tank is also housed. The electrical installation is moderately modern, the meter cabinet including main distribution is located in the basement hallway. The house connection box is mounted on the northeast side of the house, where the supply line from the utility company also enters. The routing of the telecommunications system (copper cables) is still unclear at the present time.
An existing energy certificate has already been created (building category H). The demolition work by ourselves is already well advanced, all wall and floor coverings have been removed, all ceiling claddings have been dismantled and ceilings exposed. The building seems to have no major defects (no wet basement walls, no flakings or cracks, no mold).
Basic information about the renovation project:
The project concerns a complete renovation of an existing single-family house. The building will be completely gutted and brought to the KfW55 EE standard. In addition, extensive interior finishing measures will be carried out as well as the construction of a new balcony, a carport, and a canopy for the front door. The largest subprojects in the renovation are:
[*]Removal of the current floor slab and installation of a new, insulated and sealed floor slab. The slab will be lowered between the strip foundations; underpinning of the strip foundations is necessary to reach the minimum ceiling height of 2.2 m (currently exactly 2 m). The structural engineer has already been here and says it should be possible without major problems.
[*]Exposure of the basement exterior walls, sealing and insulating the walls (perimeter insulation) and installation of drainage around the house.
[*]Insulation of the exterior walls with an external thermal insulation composite system.
[*]Renewal of the roof including enlargement of the existing dormers (these will become wider and the pitch will be flattened to 25°).
[*]Replacement of all windows and doors as well as relocating / bricking up / creating new exterior wall openings.
[*]Installation of a new heating and hot water system. A air/water heat pump, a separate domestic hot water heat pump, and a decentralized ventilation system are to be installed.
[*]Installation of new stairs basement/ground floor and ground floor/upper floor.
In addition, a variety of smaller and larger adjustments will be made inside the house:
[*]The basement floor is to be used as living space in the future (hence the underpinning of the foundation), where an office, a utility room, and the technical room will be located.
[*]The ground floor will feature a large open kitchen, dining, and living area. Additionally, a storage room, a cloakroom, and a guest toilet will be accommodated on the ground floor.
[*]The upper floor will include the main bathroom as well as a large bedroom with dressing area. Additionally, a second office or a child’s room will be set up there.
[*]The attic will initially remain unused or will only be used as storage space.
An architect, a structural engineer, and an energy consultant are already on board and have confirmed many of my plans and provided information. Currently, the architect is working on the approval planning which should be finished in about one week. The energy consultant will then create the BZA for funding and we will proceed with financing talks. For that I now need your help or assessment. We will commission the work on our own after approval; some offers (e.g. windows, underpinning of strip foundations, perimeter insulation) are already available to me and approximately fit the following calculation. The remaining offers will arrive gradually and will be prepared based on a detailed scope of work / construction description created by me.
I know such a renovation project has its peculiarities and is difficult to assess. Our advantage is that a knowledgeable construction manager friend lives next door and will support us a lot. I have now completed the entire construction description, hence also the detailed description here. Basically, a lot will be done in self-performance; I have some time available and a few good colleagues who will help. Everything involving statics, watertightness, and other difficult or dangerous work will, of course, be performed by specialist companies. The electrical installation done in self-performance will be later inspected by the specialist company from which I will source the materials.
Overview of the current building cost estimate:
The following construction costs I have gathered from extensive research from various sources (architect, craftsmen known to me) and then roughly averaged. In the presentation, I tried to follow DIN 276 (slightly customized to my needs, please forgive me if it doesn’t fully comply with the standard). All costs are shown as gross costs.
Explanation of columns:
| Work to be performed | | Cost per unit | | Unit | | Number of units | | Total costs |
Cost group Preparation and Demolition (Please note: very much self-performance!):
| Demolition of roof | €20.00 | m² roof area | 112 | €2,240.00 |
| Demolition of interior walls | €80.00 | m² wall area | 30 | €2,400.00 |
| Demolition of exterior surfaces and balcony | €2,000.00 | lump sum | 1 | €2,000.00 |
| Demolition of floor slab | €50.00 | m² | 56 | €2,800.00 |
| Excavation and grading floor slab | €100.00 | m³ | 10 | €1,000.00 |
| Demolition of interior fittings, windows, doors | €2,200.00 | lump sum | 1 | €2,200.00 |
| Demolition and disposal of oil heating + tank | €2,500.00 | lump sum | 1 | €2,500.00 |
| Disposal of demolition material | €4,000.00 | lump sum | 1 | €4,000.00 |
| Filling and compacting carport and garbage area | €70.00 | m³ | 20 | €1,400.00 |
| Earthworks garden area | €70.00 | m³ | 20 | €1,400.00 |
| Adaptation of wastewater disposal | €2,500.00 | lump sum | 1 | €2,500.00 |
| Adaptation of water supply | €1,500.00 | lump sum | 1 | €1,500.00 |
-----
Cost group Foundations:
| Insulated floor slab old building | €220.00 | m² | 56 | €12,320.00 |
| Underpinning basement foundations | €45,000.00 | lump sum | 1 | €45,000.00 |
| L-blocks garbage area | €450.00 | linear meter | 11 | €4,950.00 |
| Retaining walls carport in cast-in-place concrete | €350.00 | m² | 24 | €8,400.00 |
| Foundation heat pump | €1,200.00 | lump sum | 1 | €1,200.00 |
| Point foundations balcony | €250.00 | pcs | 6 | €1,500.00 |
-----
Cost group Exterior walls:
| Basement: closing exterior wall openings | €200.00 | m² | 4.4 | €880.00 |
| Perimeter insulation basement exterior walls soil excavation | €60.00 | m³ | 58.5 | €3,510.00 |
| Perimeter insulation basement exterior walls prepare base | €30.00 | m² | 36 | €1,080.00 |
| Perimeter insulation basement exterior walls sealing bitumen thick coating, insulation, studded membrane | €160.00 | m² | 36 | €5,760.00 |
| Perimeter insulation basement exterior walls drainage, filter package | €90.00 | linear meter | 25 | €2,250.00 |
| Perimeter insulation basement exterior walls backfilling | €50.00 | m³ | 60 | €3,000.00 |
| Ground floor: closing exterior wall openings | €200.00 | m² | 6 | €1,200.00 |
| Ground floor: creating exterior wall openings | €700.00 | m² | 6 | €4,200.00 |
| Ground floor: masonry interior walls / install supports | €5,000.00 | lump sum | 1 | €5,000.00 |
| Upper floor: closing exterior wall openings | €200.00 | m² | 2 | €400.00 |
| Upper floor: creating exterior wall openings | €700.00 | m² | 2 | €1,400.00 |
| Facade insulation (160 mm mineral wool boards) | €140.00 | m² | 180 | €25,200.00 |
| Facade plastering, painting, and sealing | €80.00 | m² | 180 | €14,400.00 |
| Windows and side entrance doors including shading | €1,000.00 | m² | 36 | €36,000.00 |
| Front door | €6,000.00 | lump sum | 1 | €6,000.00 |
-----
Cost group Interior walls:
| Drywall | €85.00 | m² | 14 | €1,190.00 |
| Interior doors | €1,000.00 | per door | 7 | €7,000.00 |
| Sliding doors | €1,200.00 | per door | 3 | €3,600.00 |
| Plastering work | €40.00 | m² | 80 | €3,200.00 |
| Wall tiles bathroom and kitchen | €130.00 | m² | 27 | €3,510.00 |
| Filling and sanding (painting and wallpapering is self-performance) | €30.00 | m² | 400 | €12,000.00 |
-----
Cost group Ceilings / Floor coverings:
| Dry screed ground and upper floors | €80.00 | m² | 100 | €8,000.00 |
| Floor covering basement | €90.00 | m² | 39 | €3,510.00 |
| Floor covering ground floor | €130.00 | m² | 46 | €5,980.00 |
| Floor covering upper floor | €90.00 | m² | 37 | €3,330.00 |
| Floor covering bathroom | €90.00 | m² | 9 | €810.00 |
| Insulation basement ceiling | €50.00 | m² | 48 | €2,400.00 |
| Insulation ground floor ceiling | €50.00 | m² | 46 | €2,300.00 |
| Ceiling cladding | €40.00 | m² | 148 | €5,920.00 |
| Stairs basement --> ground floor | €7,000.00 | lump sum | 1 | €7,000.00 |
| Stairs ground floor --> upper floor | €7,000.00 | lump sum | 1 | €7,000.00 |
| Access attic | €1,000.00 | lump sum | 1 | €1,000.00 |
-----
Cost group Roof:
| Re-roofing and insulating (roof insulation above rafters) | €340.00 | m² | 89 | €30,260.00 |
| Adjustments to dormers / roof structure | €9,000.00 | piece | 2 | €18,000.00 |
The new roof area will be considerably smaller due to the changed dormer pitch; therefore, only 89 m² of roof will be re-covered and insulated.
-----
Cost group Water supply and wastewater disposal, sanitary:
| Water filter and softening system | €5,000.00 | lump sum | 1 | €5,000.00 |
| Hot water heat pump | €4,500.00 | lump sum | 1 | €4,500.00 |
| Water and wastewater pipes | €18,000.00 | lump sum | 1 | €18,000.00 |
| Toilets | €500.00 | pcs | 2 | €1,000.00 |
| Bathroom washbasins | €500.00 | pcs | 2 | €1,000.00 |
| Walk-in shower | €4,000.00 | pcs | 1 | €4,000.00 |
| Additional external connection | €1,000.00 | lump sum | 1 | €1,000.00 |
-----
Cost group Heat supply:
| Air-water heat pump | €20,000.00 | lump sum | 1 | €20,000.00 |
| Installation of underfloor heating | €9,000.00 | lump sum | 1 | €9,000.00 |
-----
Cost group Ventilation systems:
| Decentralized ventilation system with heat recovery | €13,000.00 | lump sum | 1 | €13,000.00 |
-----
Cost group Electrical installation (Please note: all will be done by ourselves with a few colleagues, we are all electricians. So here only material costs are meant. Overall it shall represent a very high-end equipment level):
| Basic electrical installation | €10,000.00 | lump sum | 1 | €10,000.00 |
| Extended distribution board including smart home components | €9,000.00 | lump sum | 1 | €9,000.00 |
| 5 kWp photovoltaic system | €10,000.00 | lump sum | 1 | €10,000.00 |
| 7 kWh battery storage | €3,000.00 | lump sum | 1 | €3,000.00 |
| Wallbox | €1,000.00 | lump sum | 1 | €1,000.00 |
-----
Cost group Traffic areas:
| Paving work driveway, carport, and terraces | €80.00 | m² | 150 | €12,000.00 |
| Erection of carport | €8,000.00 | lump sum | 1 | €8,000.00 |
| Entrance area: roof and steps | €5,000.00 | lump sum | 1 | €5,000.00 |
-----
Cost group Fencing:
| Hedges | €80.00 | m | 52 | €4,160.00 |
-----
Cost group Outdoor facilities:
| Balcony (elevated steel balcony with garden stairs) | €650.00 | m² | 30 | €19,500.00 |
| Terracing garden (creating levels) | €8,000.00 | lump sum | 1 | €8,000.00 |
-----
Cost group Planning costs:
| Architect phase IV | €80.00 | hour | 70 | €5,600.00 |
| Structural engineer | €3,000.00 | lump sum | 1 | €3,000.00 |
| Energy consultant | €89.00 | hour | 70 | €6,230.00 |
| Surveying / setting out | €1,000.00 | lump sum | 1 | €1,000.00 |
-----
Cost group Approval:
| Preliminary building inquiry, building permit, and other official approvals | €2,000.00 | lump sum | 1 | €2,000.00 |
-----
Cost group Construction-related additional costs:
| Scaffolding erection and rental | €30.00 | m² | 156 | €4,680.00 |
| Construction road / preparation of gravel area in front of the house | €5,000.00 | lump sum | 1 | €5,000.00 |
| WC, general facilities | €1,000.00 | lump sum | 1 | €1,000.00 |
| Construction power supply | €500.00 | lump sum | 1 | €500.00 |
In total, this amounts to approximately €540,000 including all the above listed cost items and the already incurred disposal costs. The earthworks are quite detailed but are already included in several positions. Here we also have access to a mini-excavator and a landscaper who will do it at a reasonable price. Due to the large plot, much of the soil can be reused in the garden for lawn base layers.
The execution planning is carried out by the architect on an hourly basis where necessary (everything regarding statics and watertightness). The rest shall be planned by the trades or by ourselves. The construction management (and coordination of the execution planning) is done by the neighbor, who we are good friends with and who professionally works as a construction manager.
The house already belongs to us and is thus part of the equity. The house will later have (including creditable balcony areas) a living and usable area of 156 m², resulting in about €3,400 / m² construction costs.
What is your assessment of the planned works? Does it roughly fit or am I significantly below / above your cost estimates in one area or another? Attached you will find the current drafts, which still have some detailing work. Afterwards, it will go into approval, whose preliminary inquiry has already been positively decided.
Thank you very much for reading and (if you like) answering. I am grateful for every tip and look forward to your questions.
Best regards!