Cost estimate for major renovation

Hello everyone,

I am new here in the forum

My husband and I are looking for a house in the tight real estate market in the Rhine-Main area. We are not under time pressure and started searching about 4 weeks ago.

We find it very difficult to assess old houses. Newer houses often exceed our budget. Occasionally, we see an old house that might be interesting in terms of price, provided that the renovation and refurbishment costs remain within a certain range. And this is exactly where we struggle. There are many guides and calculators online, but somehow the costs indicated there, even if you take the upper limit in the "from-to" estimates, always seem very low to me.

For example, we have now seen an old house from 1900 where we still have about 300,000 Euros of leeway in our budget. But is that enough? We don’t know. Of course, if it becomes relevant, we would go through it with an expert etc. But for the further search, it would be good to know what kind of costs one can expect.

Of course, I am aware that there are very large ranges here and that it also depends on the specific house and what exactly we want to do. But just to get a feeling: in what dimensions do the costs lie if "everything" has to be done and the whole thing should still be reasonably energy-efficient so that you preferably get funding? By "everything" I mean:
- Insulation of the walls, basement, and roof
- New roofing
- Replace heating system
- Replace pipes
- Renew electrics
- Replace radiators or better still: install underfloor heating
- New staircase
- New windows
- Install electric shutters
- New doors
- New front door
- New bathrooms
- Replaster house
- New exterior paint
- Moving/breaking through possibly load-bearing walls to create larger rooms
- Attic conversion

I am not sure if I have really thought of everything, but these are the points I am thinking of. For a detached house with about 140 sqm, what costs should one expect here? Very roughly?

Logically, after that, floors would still have to be laid, walls painted/wallpapered, a kitchen installed, and the outdoor area landscaped. But since that is really very individual, I would not include it in the costs for now.

And another question: we often hear from friends that it is currently very difficult to find craftsmen. Is it possible in a worst case that such an extensive renovation/refurbishment would be affordable and feasible, but you can’t find anyone to carry it out?

I hope the questions are not silly, but we really find it difficult to properly estimate something like this. We would be very happy about opinions etc.

Best regards!

So from my own experience, there is almost nothing one can say about it from my point of view. Because it depends on so many factors, and then individual items can vary greatly. For example, we had costs for replacing our windows + front door and side entrance door ranging from just under €20,000 up to €38,000, and the most expensive offer even included worse windows.

What can be said is that €300,000 is initially still a good margin. And depending on the house, it should also be sufficient, but it does not have to be (also depending on your wishes). Of course, there are various funding programs that can be used, so it is already a good basis. But as an example, you can renovate a bathroom for €10,000, but also easily for €20,000 or even more.

I believe that can be beautiful but also very dangerous. As soon as you have to get down to the nitty-gritty during renovation, like statics, piping, windows, etcpp., even for a professional it's not always easy to foresee it as a whole. If you occasionally see something interesting in the price, it probably has its reason. As a layperson (and I am despite somewhat basic knowledge) I would never get involved in such a project. Maybe you need to change the radius a bit or......adjust the expectations somewhere else but buying and renovating an old property can end badly. It doesn't have to - but it can.

Flat rate from 1,000-1,200€ per sqm as renovation costs. Creating new living space will be more expensive (possibly architect + building permit etc.). With own labor, still significantly cheaper (insulating the basement ceiling, for example, is doable even with two left hands).
In the end, it depends on the standard you want or the energy level you are aiming for.
That actually "everything" needs to be done is rather rare.

KfW-430 program as a grant option or 151/152 as a loan option. In addition, the Bafa subsidy for heating as well as KfW 431 for construction supervision. These are the main programs.

Very important for the house from 1900. Monument protection. Are there possibly elements of the house that are under monument protection? If not, the guideline value of 1,000 - 1,200 € is okay. If yes, it becomes much, much more expensive.

Good morning Sirooris,

about ~1.5 years ago we faced the same questions when we decided to buy a single-story house with 120sqm fully basemented from 1971 in our preferred location in the Rhein-Main area. Our plan from the beginning was to completely overhaul the house and redo everything, including major changes to the floor plan + doubling the living space by building up a knee wall.

We planned a lot of work ourselves, but commissioned the key trades such as: new floor in solid construction, roof structure/roof, gas-water-bath, windows to specialist companies.

To give some orientation about the prices, I am writing below on your list what came up for us as far as we are already through or have offers.

- Insulation of walls, basement and roof
Basement insulation outside (bitumen and dimpled membrane), drainage, inspection shaft with excavation work 7,000€.
Insulation of basement ceiling material for 120sqm costs about 2,500-3,000€, we will do it ourselves at the end or after moving in. Exterior wall insulation

- New roof covering
Dismantling the old roof + roof structure took 1 Saturday with 5 people, 2,000€ disposal (however with gables).
New roof structure + roof including 4 roof windows with electric shutters 46,000€
- Replace heating
Removal of the old oil tank by a specialist company cost 1,200€.
Dismantling the old heating took 3 hours of self-work with 2 men.
New gas condensing boiler with solar and underfloor heating in drywall system (necessary due to floor build-up height in the existing building) plus completely new piping + second heating circuit for towel warmers in the bathrooms as well as new water pipes costs 48,000€
- Replace piping
Is included in the heating position.
- Renew electrical installation
Is completely done as self-work, costs an incredible amount of time: preparation by studying and executing. In the upper floor it is going faster now as I have some practice. New fuse box connection and later connection of the cables is done by a friendly master electrician (who thankfully also checks my self-work), so the price is not representative. However, I probably come to about 10,000€ including switches program for the material.
- Replace radiators or better: install underfloor heating
Heating is included in the position above. The underfloor heating in drywall system costs about 19,000€ + 2,000€ for insulation and 5,000€ for dry screed on nearly 240sqm floor area. The 19,000€ is included above, so here only +7,000€ to bring the floor ready for covering.
- New staircase
We had a concrete staircase poured on site which was probably quite cheap at 2,500€. However, it must be treated afterwards, so about 3,000€ in the end. The railing and handrail are drywall for us, we cover the handrail with Nero Assoluto as well as the window sills and kitchen countertop. The marble 700€.
- New windows
All windows new with electric shutters including large lift-slide door and aluminum front door and basement windows cost us about 30,000-35,000€. According to the offer it was 28,000€ without basement windows, I don’t have the final invoice yet, only a partial invoice.
Electric garage door with remote control about 2,000€
- Install electric shutters
- New doors
About 200-300€ per door with frame
- New entrance door
Is included in the window price. Ours is completely anthracite with 2 80cm wide light shafts left and right and costs about 3,000€ according to the offer
- New bathrooms
We were at the sampling appointment 2 weeks ago and are still waiting for the offer. We have a reference from the same sampling company and an equivalently expensive installer from the area from family, which was 20,000€, because we have somewhat larger showers and a bathtub, I rather estimate 30,000€
- Newly plaster the house
I’m still waiting for an offer, according to the architect’s estimate 25,000€ including exterior insulation. But I guess it will cost more with insulation.
- New exterior paint
Included in the plastering
- Relocation / breakthrough of potentially load-bearing walls to create larger rooms
This cost us the most time of self-work on the ground floor. The entire demolition, conversion, installation of steel beams, partially re-bricking, etc. took about 6 months with an average of 20 working hours per week. The costs were highest for disposal (this also includes removing the asphalt screed, etc.).
Disposal: approx. 10,000€, I didn’t calculate precisely
Conversion material: 5,000
- Attic conversion
Building the knee wall 1.20m + gable and load-bearing interior walls and chimney 37,000€
Non-load-bearing interior walls from drywall, under-rafter insulation roof, knee wall from OSB insulated, all clad with OSB and drywall as plaster for the ground floor cost (material only) 6,000€.
Self-work in working hours 150 hours.

Additional costs were like site setup with crane and scaffolding ~7,000€ for 5 weeks
Architect phases 1-4: 6,000€
Structural engineer: 2,500€
Building permit: 800€

Site management is handled by my grandpa as a civil engineer, so free of charge. The architect would have charged 10,000€ for that.