How to realistically assess personal effort?

Hello forum community,

I actually wanted to create the thread only after the appointment with the planning office. Hopefully, there will still be optimizations and then a concrete plan will be available. As discussed in another thread, however, it seems helpful to involve you beforehand :)

Background:
The plot is available, 1800m², slope across the house width 6% and across the house length 9%. The plot is to be mostly leveled and smoothed. Connections are already at the plot boundary.

We are currently thinking of a single-family house with a granny flat (necessary), 240m² living area (terraced house, solid construction). Originally planned as KFW40+, it will now be something between KFW55 and KFW40. The budget for the house, including buffer and own contribution, is 500k.
Location is a rural area in Lower Bavaria.

Construction time is not our focus. We aim to move in by 2025; if it takes a year longer, that’s also okay.

An important item is the own contribution that we want to bring in, which now needs to be realistically considered and calculated, and I am very curious about your critical opinions.

People usually overestimate themselves (or their family), as you know :)

Professional support from the family:
- Electrician
- Painter

Professional support from friends:
- Heating engineer
- Carpenter

Layman support:
- 5 people

I myself bring:
Experience as a helper on various construction sites including hall construction, single-family house demolition/construction and core renovation of an old building.
From laying floor/external insulation, laying laminate, pulling cables, paving, concreting strip foundations, milling slots, drywall work, roofing, installing wood cladding to laying trench collectors, I have done everything in practice. Operating mini excavators, vibrating plates, concrete mixers, and tractors is also familiar territory.
Time: Annual leave, 1-2 months leave per year, weekends and evenings.

Already available or usable at no cost:
The usual tools of a well-equipped workshop in multiple copies (miter saw, angle grinder, drills, hammer drill, cross laser, wall groove mill, etc.)
Forced concrete mixer
Telescopic work platform
Tractor + trailer
Tractor with front loader
3.8t mini excavator
Water
WC and snack supply :) in the neighboring house

Planned as own contribution so far:

- Laying of trench collector
- Trenches for development
- Laying electrical installations
- Laying ventilation pipes
- Suspending ceilings
- Painting work
- Outdoor facilities
- Creating slots/breakthroughs
- Floor insulation
- Laying floors
- Paving work
- Minor woodworking (e.g., construction site stairs)
- Roof covering (hanging tiles, installing photovoltaics)

Now the question is whether my intention is even monetarily calculable?

All helpers including me still have a full-time job. Considering 3k/m² as fixed, how much of that can realistically be "worked in" during their free time? Does it even make sense to include the own contribution in the planning in detail? Or simply roughly estimate 50k for own contribution and deduct that? Can construction prices really be generalized so that each sqm strictly costs at least 3k?

I look forward to your input!

Now the question is whether my request is even monetarily calculable?

This is normally determined (for the bank) by the architect. Your planning office should take care of this for you and calculate the labor costs for the EL. Of course, you still need the materials.

Can construction prices really be generalized to the extent that every sqm strictly costs at least 3k?

Depending on the region and customer requirements (equipment, type of building, size, etc.), yes. But it remains a rough estimate without consideration of EL. You can of course also buy from the developer for €2,000. You get what you pay for! People also find happiness in that (and especially young families are often happier there than in individually planned single-family homes). By the way, EL also cost money – commitment interest on the financing. You must not hide or forget that.

Hey, interesting question. Basically, it was also a significant issue for us at the beginning. In the end, we deviated generously from it for the following reasons: - EL on a larger scale is only possible if you can be on the construction site quickly and effectively. Stopping by briefly after work and on weekends can take forever, must be constantly coordinated with all subcontractors, and can severely strain the relationship. - Ultimately, you only save labor costs. One foreman plus two journeymen cost triple the wages but work at least 4 times faster than you. This means one week of EL costs you a month. - If you pay rent alongside, you have to offset this against the potential loss of earnings from the withdrawn EL. - Some trades do craftsman work because they are apprenticeship professions and often not DIY tasks. - The construction manager must share liability for EL work or insure it accordingly. - Downtime in EL means downtime for all subsequent trades. Basically, you don't bring time pressure, which is good. In the current situation, however, time is your greatest enemy. Six months waiting time or delay can mean 5% higher material costs/wages and inflation losses. You can't earn money fast enough and work hard enough to keep up with rising costs. We have evaluated EL for work that does not prevent us from moving in. For example, floors in less relevant rooms. The garage and outdoor facilities can be done by yourself. But in my opinion, the ready-to-occupy building shell should be completed as quickly as possible. Additionally, friends can also fail you sometimes. Or they don't work like a liable installer because, after all, they don't enter into an employment contract with you. Overall, the topic should be approached with caution. But I tip my hat to anyone who consistently takes such a project into their own hands from A to Z, fully aware of all risks.

Don't let the people here in the forum convince you that it can't be done. And even that 3000 euros per square meter is only correct if you don't want to lift a finger yourself.

I started building a townhouse in timber frame construction 2 years ago. Without a basement on a slab. I did everything myself. Craftsmen were only a master carpenter for assembling. For 4 hours a civil engineering company for concreting the slab and the window installers. You have much better conditions than I do. So do it. My villa is now completely finished on the outside and has 192 square meters of living space and I still have about 1.5 years of interior work ahead of me. It has cost me 148,000 euros so far. If I invest another 100,000 in the interior, I will be at around 1300 euros per square meter. But then it’s a palace. Including a 45 meter long driveway. I’m just paying with 3.5 years of my life. Go for it, it’s the best thing I have done in my life so far!

Corona taught us one thing: construction planning can be difficult to calculate even with professional companies, with friends and relatives you can almost forget about it. And a problem not to be underestimated: discussing shoddy workmanship and consequential damages, construction delays, etc. with friends and relatives does not make you happy. Added to this are liability and insurance issues,…

Don't let the people here in the forum tell you that it can't be done. And those 3000 euros per square meter are only correct if you don't want to lift a finger yourself.

I started building a city villa in timber frame construction 2 years ago. Without a basement on a slab. I did everything myself. The craftsmen were only a master carpenter to set it up for 4 hours, a civil engineering company for concreting the slab, and the window installers. You have much better conditions than I do. So do it. My villa is now completely finished from the outside and has 192 square meters of living space and I still have about 1.5 years of interior work ahead of me. So far it has cost me 148,000 euros. If I invest another 100,000 in the interior finishing, I'm at costs of about 1300 euros per square meter. But then it's also a palace. Including a 45-meter-long driveway. I pay with 3.5 years of my life. Go for it, it’s the best thing I’ve done in my life so far!

I am not talking the OP out of it. I just want to separate naivety from realism. 3.5 years… That corresponds to 55k euros rent for us…

As I said, if you have the time and family support, I endorse such decisions.

I want to help the OP also consider the downside.