Asked 4 people - got 5 answers...

Dear forum,
we are about to purchase a hillside plot of about 1000m2 (approx. 16° slope, west-facing slope). It is actually larger than what we are looking for, but otherwise it fits so far.

Of course, we have many questions as every building beginner does, and we have asked these to various "experts." Starting from our 2 potential architects to different prefab builders. It is clear that everyone speaks from their own perspective, yet the statements are so contradictory that I cannot plan further on that basis.

Therefore, I am trying here to get an overview ;)

Is a flat roof for a 90m2 area equal in cost to a hipped roof (10*8m @ 15°)?

Is it cheaper to fully develop a basement as a living basement (with a large window front) than to keep it as a dark (insulated) utility basement (cladding the visible part with wood) and instead build an upper floor fully developed like a living floor?

Is it rather cheaper to use part of the front basement ceiling (possibly 3*4m) as a terrace than to use a part of the ground floor in the upper floor as a terrace?

In summary, we need about 130m2 living space, 15m2 terrace (at least at the height of the basement ceiling) and about 30m2 utility space for workshop, storage room etc.
The plan was actually to forgo the upper floor and instead build a fully functional living basement. We cannot reduce the floor plan infinitely since we want a living & kitchen area of 10m*6m to enjoy the hillside view. I actually wanted to attach the terrace as a wooden construction from the living room (ground floor above the living basement) to the side or front. Now I was told it is common to "simply" use the surface of the basement ceiling for that. We are not planning anything special, rectangular floor plan with flat or open hipped roof.

Thanks for any tip, maybe someone knows a similar house with our wishes?

Regards

Pit

Good evening Pit,

we are about to purchase a hillside property of around 1000m2 (approx. 16° slope, west-facing hillside). It is actually larger than what we are looking for, but otherwise the rest fits so far.

You must have a lot of time :D

Is a flat roof on a 90m2 area equal in cost to a hip roof (10*8m @ 15°)?

No. The flat roof (FR) is – if done properly – more expensive.

Is it cheaper to completely convert a basement into a living cellar (with large window front) than to leave it as a dark (insulated) utility cellar (cladding the visible part with wood) and rather build an upper floor with equal living standard on top?

No – but the question is still not that easy to answer. From my point of view, a basement only makes sense if it is actually used as living space. This is usually recommended if the plot has a hillside location.

A pure utility cellar is the most expensive way to generate floor space you can imagine. Also because – since there is plenty of garden – it is increasingly used as an expensive storage space. At first, it’s just a box, later perhaps a piece of furniture that one doesn't want to give up, etc. In the end, almost every utility cellar is cluttered with, in my opinion, useless junk that one will never properly use again anyway.

An 80 sqm utility cellar with partially exposed exterior masonry should cost around EUR 50** thousand. If it is now converted into a living cellar – apart from a utility room – you should expect additional costs in the range of EUR 15** thousand (insulation, expansion of the heating system, underfloor heating, screed...).

A single-family house 10.00 m x 8.00 m – two-story, KfW 70, with FR – should cost around EUR 172** thousand, the utility cellar about EUR 50** thousand (with exposed masonry, plus further conversion to a living cellar).

A bungalow (i.e., single-story) – same parameters as above – also costs EUR 172** thousand plus the costs of the utility cellar and further conversion to a living cellar.

But since you will have a basement anyway, it is – again in my opinion – pointless to spend more money on an upper floor you don’t need. Better to convert the basement into a proper living cellar.

Is it rather cheaper to use the front basement ceiling partially (possibly 3*4m) as a terrace than to use part of the ground floor as a terrace in the upper floor?

Why basement ceiling? You mean you want to cantilever the basement ceiling?

I actually wanted to build the terrace as a wooden structure off the living room (GF above the living cellar) to the side or front. Now I was told it is usual to "simply" use the surface of the basement ceiling for this.

It would be "usual" if the basement level were larger than the ground floor above.

** in Bavaria you may have to calculate costs 3-5 times higher depending on in which district you want to build.

Rhine greetings

Hello construction expert, first of all, thank you very much for your detailed answer!

Can you roughly estimate how much more expensive the FD is compared to the WD or even an SD with about 15°?

If I understand you correctly, you mean we will need a basement anyway because of the slope, so it also makes sense to fully develop it rather than just use the basement as a storage room. I totally agree with you here, but I still see two advantages in a 2nd upper floor: 1. It will be brighter in the room upstairs and the view would be nicer 2. The basement can be more easily converted into living space later on, retrofitting a 2nd upper floor is certainly more complicated!?

Why do you think the basement can cost 3-5 times more in Bavaria? Are you thinking about the excavation? We are not really in Bavaria ;) we are in Franconia at a vineyard – is your assessment the same here?

Why basement ceiling? You mean you want to cantilever the basement ceiling?

Yes exactly, we thought of making the basement floor partly larger than the ground floor, but not across the entire width because we don’t want to obstruct the view too much from a balcony (we are considering floor-to-ceiling windows). Here we are rather thinking of adding a kind of terrace around the corner on the side, accessible from the ground floor.

If I understand you correctly, you calculate with a developed basement and a 2nd upper floor at around 240,000€, so if we skip the basement development, we only save "15-20,000€"? How much additional construction cost would you still estimate (the land is fully developed up to the property)?

And the last question, who would build me the described house for this price?

Many thanks in advance!!

Greetings from Franconia!

Instead of a flat roof, possibly use a shed roof with a 3° pitch. Covered with roofing felt or metal. This is very close to the flat roof and is one of the most affordable roof options due to its simple construction and low material usage.

Hello,

Can you roughly estimate how much more expensive the FD would be compared to the WD or also an SD with around 15°?

Certainly in the range of about EUR 5-8 thousand

2. The basement can be more easily converted into living space afterwards, adding a 2nd floor is certainly more complex!?

In my opinion, both are roughly equal - although converting the basement into living space afterwards becomes difficult if you have not already taken into account a floor height increase, insulation and larger dimensioning of the heat generator during planning.

Why do you think the basement can cost 3-5 times more in Bavaria? Are you thinking of the excavation? We are not really in Bavaria ;) we are in Franconia on a vineyard is your assessment the same here?

I don’t think - I know. In Bavaria - and Franconia is part of that - construction prices are simply higher.

How much additional construction incidental costs would you estimate (the property is developed up to the property boundary).

Sorry, but I can’t responsibly estimate that. I don’t know the soil conditions; nor the property nor the costs for gravel or whatever the geologist prescribes.

And the last question, who will build the described house for me at this price?

Ask here in the forum and request an answer via private message. I’m sure you will receive numerous proposals.

Rhenish greetings