Hello,
Or rather, what do you think it should cost? Shell construction as own work, chasing slots, tiling outside, installations, etc. as well.
I simply cannot answer that for you, as I do not know what purchasing conditions are available to you!
But I can tell you what a comparable finishing house would cost here; then at least you have a reference value if the
refined shell construction is delivered completely from one source.
Almost every provider has a similar house on offer because no one can reinvent the wheel. For us, refined shell construction means: foundation slab, exterior walls including mineral external plaster, interior walls, window trades (7-chamber profiles as well as increased burglary protection on the ground floor with up to 9 mushroom heads) with manual shutters including front door, carpenter & roofer trades as well as tinsmith work. The building envelope is therefore completely made. Such a finishing house costs in NRW and for 148 sqm/GF TEUR 138; including structural engineering, soil survey and earthworks (removal of topsoil and foundation) as well as appropriate securities + warranty. Certainly more in Bavaria; depends also on the region of Bavaria in which you want to build.
If I now look at the listing of both offers for the kit houses, they realistically refer to a simple shell construction
without external plaster, without required soil survey or foundation; I cannot find any information at all regarding the foundation slab. This means you must still add these costs to the pure offer costs; from an accounting point of view even consider your own working time. Therefore, the offer price is, for me, outside of an economical saving to take on this risk. You are sweetened with a chimney flue, a stair flight and a kitchen; all considerably cheaper to have than the missing trades.
I always have problems when potential builders assume they can just pull up a house themselves. Apart from the necessary knowledge and time commitment, from my experience it is always a risk for any partnership; such a thing can easily take 2 years. When I have these conversations, I recommend (only if experience is available) either to purchase from finishing shell construction from one source or to work together with a trusted architect.
It is true that most money can be saved with a shell construction; but it is also true that a lot of knowledge must be available for this part of the new build – expert construction supervision is therefore indispensable. Whether this is the inventor’s intention with a stones + construction management package, I cannot judge; I have too little contact with this type of house construction.
To finally evaluate the offer, you have to see what it would cost you to organize the foundation and to buy the bricks and other materials. Alternatively, you can talk to an architect and commission him with the task "considering much own work" to obtain appropriate prices. Only when you can make reliable comparisons – with all consequences – can you in my opinion make a decision.
Rhenish regards