Experiences with construction cost savings through self-performance?

Especially since it is not significantly cheaper to include the material and tools for the self-performed work at 3.5% in the mortgage over 15 or 20 years, instead of taking a private loan at 5% over 5 or 6 years. But it does significantly reduce the burdens from the installments at the beginning, when money is usually tight.
I read that children are also planned, just wait and see what costs are still coming your way...

I don't understand where it comes from that I want to take out a private/consumer loan for the material of the self-performed work? I never said that?!

I have a completely normal construction financing running.
The house costs 400k. I calculate earthworks and additional costs at 60k and carport plus outdoor facilities initially at 25k (and yes, that means just a fence and lawn in the garden – I believe we don't need to discuss that).

That's 485k plus the land (which has already been bought from equity).
400k loan and 50k equity are declared at the bank. The 35k for the carport and outdoor facilities is primarily a reserve for the house (in case there are additional costs during construction). Then there simply won't be a carport or a fence for the time being.
But if I include it in the financing, that is 400k loan and 85k equity, then I have the problem that I have to spend the equity first before I can draw down the loan. Afterwards, I either do not draw a significant sum from the bank or have to pay commitment interest.

Moreover, the interest rate does not change with more equity, since the 60% threshold is not reached.
Or am I missing something?
Equity in financing must be “spent” first. This way, I take a greater risk of falling into the commitment interest and possibly end up not taking out a sum at all.

Equity in financing must first be "spent." Otherwise, I take a greater risk of falling into commitment interest and possibly ending up with a non-acceptance of an amount at the end.

I've also read that several times. But it wasn't like that in my two construction financings. The one for the owner-occupied home was with the Sparkasse. The financing for building a two-family house to rent out was with the VR-Bank. Both times, this topic played no role. Otherwise, everything was/is quite uncomplicated. I am building the two-family house together with my brother. The bank always accepts the division in the invoices, for example, how we proceed, e.g., 50/50, 100/0, 20/80, or whatever.
I think it depends on the bank.

I don’t understand where the idea comes from that I want to take out a private/consumer loan for the material of the own contribution? I never said that?!

I initially assumed that you would also take borrowed money for that. That you instead use equity for it is fine – but treating it like it’s invisible in the financing calculation is clumsy. Besides, equity is practically borrowed money too (albeit from oneself) and also costs interest (a return you can’t simultaneously have elsewhere).

Equity in financing must be “spent” first. That way I take a greater risk of falling into commitment interest and possibly ending up not purchasing a certain amount.

I have also read that several times. But that wasn’t the case in my two construction financings.

Having to “spend equity first” belongs to Alg II, but not to construction financing. There, equity should serve agility. Having to spend it first would also be totally counterproductive because you mainly need it “later in time.” Nobody does gardening work and buys a kitchen before laying the foundation.

I am building the two-family house together with my brother. The bank always accepts the split on invoices as you proceed, e.g. 50/50, 100/0, 20/80, or however.

Do you have the same bank that has also known you for about the same length of time?

Equity in financing must first be "spent".

We generally always do it this way. Equity first, then debt. Only in exceptional cases different - that is then individually justified.

I. Do you have the same bank that has also known you for about the same length of time?

In fact, the financing is with different banks.

Having to "spend equity first" belongs to Alg II, but not to construction financing.

We basically always do it that way. First equity, then debt capital. Only in exceptional cases differently - that is then individually justified.

So now it confuses me. Do banks all react differently? I was told by a financial advisor, first equity and then debt capital. The bank wants to have the security that you will actually contribute it.