Cost estimation for interior finishing, any experiences?

Hello Chris,

For example, I have an offer for a turnkey house with 180 m² including basement without a white bathtub for 260,000 EUR.

That can certainly be considered a standard house - the BB should provide clarification here. However, from experience, I am sure that my assessment in the end (after adjusting the BB to personal wishes) will come very close to reality; indeed, 200 sqm living space will be built.

As for ventilation ... yes, that is currently a main topic of discussion with us. I have not yet encountered one that is inaudible even in show houses (where I think they make a special effort to sell their services).

You are just a typical German: when we are told about noises, we actually hear them.

However, I must also say that my father has had a solid house for over 20 years (36.5 exterior wall, exact composition I do not know though).

Twenty years ago, smart craftsmen still installed ventilation slots at the window reveal; today all that is no longer allowed.

But as you rightly say, we will have a professional energy consultant advise us again.

Great.

Kind regards

How airtight is your father's house? How often and what is cooked, how many people need to shower, how much laundry needs to be dried. These are all factors that influence indoor humidity. If you want to tilt the windows open, just turn off the system. Either automatically with pressure sensors or window sensors, or manually via the terminal in the living area (if you don't want to go to the basement). Besides, you will have the system in the basement, in the show homes there is usually no basement. Or do you hear the ventilation slots? Houses built today are simply extremely airtight, and there is always a risk, especially if you have many plants or ventilate irregularly, of getting mold. But like with everything, there are pros and cons.

I hope you also understand that turnkey is not equal to turnkey? There are huge differences in what construction companies understand by that. As far as I know, the term is not protected/regulated. Please check and have the construction service description examined exactly to see what is missing. Once you know what is missing, ask for the cost, and have everything put in writing. What is not written down is considered not agreed upon. You can say a lot in initial talks.

Turnkey is not always the same as turnkey is really true. There are huge differences in the construction and service descriptions in some points. Especially when it comes to excavation and construction electricity and water, there are fundamentally different promises or none at all.

So in our rental building, a ventilation system is installed. It is incredibly annoying. There is no way to turn off the fans (because then other apartments would be "affected," I think), in rooms with ventilation (kitchen, guest WC, and bathroom) an extremely loud fan noise can be heard (the possibility of hearing a draft no longer exists). I took the trouble to unscrew the covering to take a look at it. Looking at the filters made one feel sick; they probably have not been changed since construction (we haven't lived here long, and when we moved in, the ventilation seemed practical to prevent the question of why we took the apartment despite such a nuisance). In addition to having to spend another 10,000 EUR on such a ventilation system, there are constant maintenance and servicing measures that do not require open windows. In, I would say, higher-quality systems, it is not as extreme as in our apartment, but I clearly hear a ventilation noise as loud as a normal office PC. If you turn the ventilation off, I don't hear anything anymore. So it can't be imagination. Regarding cost savings, you can forget about these ventilation systems with heat recovery if you trust numerous studies from Fraunhofer & Co. I am happy to be proven wrong, but with ventilation systems, that really is difficult. In addition, you often read that ventilation systems make indoor climate anything but healthy. For example, much too low humidity, which is also confirmed in our apartment. 30% is regularly fallen below in some rooms.

The windows in my father's house have wooden frames and are double-glazed with argon filling (U-value approx. 2 on average). The U-value of the envelope is about 0.4 (estimate based on AutoCAD Revit). There are no plastics or plastic parts on the window except for the seals (normal rubber?). There are few plants, and showers are taken normally. After showering/bathing, the window is simply opened. Similarly, when the dryer is running, the window is tilted (in rain) or completely open.

Dry air can be regulated by an enthalpy heat exchanger. But also just hanging laundry or having many plants.

Talk to people who have such a system, I haven’t met anyone who wasn’t completely enthusiastic. I mean personally, colleagues, or similar. You can also test-listen to something like that on site

PS. you can’t hear my office PC

Elsewhere I just read that, unlike the general contractor, an architect is not allowed to offer a fixed price. I don’t quite understand that yet. I go to the architect with my idea, who makes a concrete plan. Do I already get a cost estimate there? Let’s say just roughly, then he awards the trades and notices, oh, everything costs double?! Of course, he wouldn’t be a good architect to misjudge like that, but the risk exists. I understand that you can’t fix all prices 100% beforehand, but most of it should be known BEFORE signing any contract. I don’t want to pay double afterwards than I thought before... Why is an architect not allowed to offer fixed prices? He must also present some reasonable calculation before you start building.

How is an architect supposed to offer fixed prices? He doesn’t employ craftsmen himself and doesn’t sell materials either...

At the beginning, a rough cost estimate is often made simply based on m²... meaning the architect tells you from his experience, for example, €1300 / m² of living space and €800 / m² of basement space... Now you can still talk a bit with the architect about what he typically installs/plans, and you have a rough price...

When you make a contract with the architect, the planning becomes more detailed. The architect finally creates a more precise cost calculation based on the actually planned equipment/materials etc.

With this detailed planning, the individual trades are then put out to tender... Whether these then fall within the architect’s price framework depends on his experience etc... but he will not guarantee it to you!

PS. You can't hear my office PC

Passive cooling in a fanless PC?