Construction costs for construction projects

Hello everyone

We are currently planning our construction project and want to make it as accurate as possible. Although we already have offers, we would appreciate an assessment of the costs and a possible addition to the equipment.

Here is an overview of the costs (rounded)

• Plot of land already available
• Construction costs house €26,100
• Construction costs garage €22,000
• Extras €31,000
• Incidental construction costs €17,000
• Outdoor facilities €19,000
• Kitchen €17,000
• Reserve €10,000
= €377,000

Construction service description:
- One-story city villa (setback floor) with 155 sqm & hipped roof + garage with 32 sqm
- Earthworks
- Floor slab
- Plaster facade
- Plinth cladding
- Clay roof tiles (Brass)
- Roof cladding made of plastic
- Balcony
- Terrace roof
- Windows (Schüco) with RC2 outside anthracite
- Aluminum exterior window sill in anthracite
- Front door with 2 side panels outside anthracite
- Side entrance door utility room/garage
- Electric shutters (flush-mounted)
- Staircase tiled with stainless steel railing
- Tiles €35/sqm
- Interior window sill white marble
- Electrical (Busch & Jäger)
- Sanitary (Villeroy & Boch)
- Shower WC
- Additional outdoor tap
- Extra water meter outdoor area
- Gas heating (Vaillant)
- Solar system with 300l storage tank
- Underfloor heating
- Decentralized ventilation system with heat recovery (Lunos)

Extras:
- Glass sliding door hall/living room
- Storage room under stairs
- SAT system
- Concrete floor garage
- Carpet €20/sqm
- Painter
- Outdoor spots 21 pcs + 4 motion detectors
- Additional 50 sockets
- Additional 11 switches
- 3 each network, antenna, outdoor sockets
- Ceiling spots hall/bathroom
- Sanitary sampling

Incidental construction costs
- Site plans
- Building notification
- Construction water
- Construction electricity
- Construction insurance
- Site staking out
- House connections (gas/water/electricity/telephone)
- Height survey
- Rainwater infiltration
- Connection rain- wastewater
- Inspection chimney & wastewater
- House surveying
- Construction supervision

The outdoor facilities will be carried out by ourselves. This item is therefore only for the material and possibly rentals for excavators or similar.

Thanks in advance and best regards

The decentralized ventilation system from Lunos suggests that it is the offering of a well-known franchise provider? Personally, I would never install a decentralized system in a new building, but that was not your question. The estimate seems somewhat realistic to me.

The decentralized ventilation system from Lunos suggests that it might be the offer of a well-known franchise provider?

Which provider do you suspect?

Which provider do you suspect?

I would guess Town & Country?

Additional costs of 17000 might be tight. And regarding the sanitary objects, Villeroy & Boch is very general, do you also know the series? The "standard" of objects would have cost us about 2000 for 2 bathrooms; after we upscaled, the sanitary would have been 12000...

I also don't find exterior window sills in aluminum very appealing, especially since a granite sill only costs about 80.-.