ᐅ Renovation of a Two-Family House from 1936 – Experiences?

Created on: 30 Aug 2022 17:38
L
leschaf
Hello everyone,

We bought a two-family house from 1936 in June. More about the financing can be found in this thread. We are still very happy that we bought it. Our baby is due in December, and once our second child needs their own bedroom, the apartment will become too small. We have also visited the property quite often since then and are very pleased with the location. Everything from daycare to high school is within walking distance, along with plenty of sports clubs, and more.

Since the purchase, quite a bit has happened. Our financing was based on equity and a bank loan for the purchase alone. For the renovation, we planned to use capital from the sale of another property. The sale has now been completed and brought in slightly more than our optimistic estimate (365,000€ vs. 350,000€ optimistic expectation vs. 300,000€ minimum expectation). I have to say that selling caused me more headaches than buying the new house—even though it involved significantly less money. Especially the news about falling prices everywhere unsettled us and made us worry that the buyer might pull out. We did have multiple offers, including two in the same range, but the second highest bidder reacted quite badly to being rejected. That would have meant relisting, which, due to the increased costs of living since the agreement and the age of the house, probably would have led to a lower sale price. Once the notarized contract was signed, we were able to breathe a sigh of relief.

Now the work begins. We already have an architect who we have been consulting with over the past two years while looking at houses. She has so far done all the appointments and planning free of charge and invested a lot of time. We have already met on-site with a heating engineer, electrician, and flooring specialist. All have praised the structural condition and potential of the house so far, which is very reassuring.

Here is a picture of the current exterior from the garden side:



White multi-story house with garden, trees and solar panels on the roof


The house was insulated on the outside with 8cm (3 inches) of external thermal insulation composite system (ETICS) in 1996—but unfortunately, no major energy upgrades have been made since then. According to the energy certificate, the current demand is about 220 kWh/m²/a, which for 187 m² (2,013 sq ft) of living space would mean around 41,000 kWh per year. According to gas bills, however, the consumption in 2020 (the last year it was occupied) was only around 22,000 kWh for two households living there separately. That is still a lot, and of course, we want to modernize it. During the recent heatwave, it was actually cooler in the two full floors than in our already quite cool old apartment, which I see as a good sign. The house itself has cavity solid walls.

This means the following for us:
- Insulation of the top-floor ceiling: The attic has a huge footprint and covers roughly 80% of the developed attic space. Therefore, we decided to insulate the attic floor at first, which is more cost-effective than insulating the entire roof, since we won’t need that space anytime soon.
- Insulation of the basement ceiling
- Elimination of some thermal bridges
- Completely new windows and exterior doors throughout the house

Before buying, the architect said that should reduce the demand to around 150 kWh/m²/a or less, and further optimizations might no longer be cost-effective. Since then, energy costs have changed quite a bit… so we’ll see if we address anything else (would you, for example, recommend adding cavity insulation between the two masonry layers as well? Or would that not work well with the ETICS?). What’s your realistic assessment? I would obviously like to reduce it further, but I would prefer to avoid completely rebuilding the roof.

In addition:
- Replace pipes and wiring throughout the whole house
- New radiators
- Heat pump, if it makes sense / if the house can be heated properly with one
- If heat pump: photovoltaic system (the left side of the roof in the picture faces directly south)

That’s the energy-related part. Several other works are planned as well. This is the current floor plan—the ground floor and first floor are almost identical, but both floors have a nice passage between the two right-side rooms with a sliding door that needs to be preserved:


Floor plan of a house with kitchen, hallway, bathroom, living room, bedroom, and stairs


And the attic floor plan:

Black and white floor plan with several chambers, stairwell, and dimensions.


The rough plan is as follows:

Ground Floor:

Hand-drawn floor plan sketch showing living room, kitchen, dining area, office, hallway, stairs, bathroom.


First Floor:

Hand-drawn floor plan sketch: balcony at top, master bedroom left, 2 children's rooms right, bathroom bottom, hallway.


Since both bathrooms need renewing anyway (photos from inside will follow later), we are moving them to the front, facing the street. This will free up space downstairs to open up the kitchen/dining area and allow a slightly larger bathroom upstairs than currently exists. Right now, we live with a 3 m² (32 sq ft) bathroom—it works for three people but is definitely not very comfortable 😀

I work almost 100% from home, so the office is on the ground floor. The attic layout will remain as is. It will include my partner’s craft/workroom, a guest room, and we have one extra room that is still undecided 🙂. The nice thing is that due to the steep roof, we even have higher ceilings on the attic floor (>2.60 m / 8.5 ft) than on the ground and first floors (2.55 m / 8.4 ft), with very little sloping (photos to follow).

Throughout the house, there are old wooden floorboards hidden under several layers of flooring. Fortunately, none are glued down but simply laid loose, so we already looked underneath with the flooring specialist and found the condition to be good. These floors will be restored rather than replaced! This is also a reason why we don’t want to install underfloor heating—the floorboards are too thick, probably fragile for removal, and underfloor heating would cause a chain reaction: the doors (which we also just want to restore/paint), the frames, and so on, would no longer fit. However, underfloor heating will probably be installed in the bathroom upstairs. The indoor staircase is another beautiful old wooden staircase that was hidden under carpet and will also only be restored as needed.

The architect’s first cost estimate is around 270,000€ for all measures (excluding photovoltaics). The three tradespeople who have been on site have more or less confirmed her rough calculation. Statics engineer and window fitter will visit next week—we’re excited 🙂

Current concerns:
- Can we achieve an energy level that makes a heat pump reasonably economical (we do have a lot of roof space for photovoltaics)?
- Is the rest of the cost estimate realistic?
- What surprises might still be waiting for us?
- When will it be completed? Target is early summer next year...

We look forward to your feedback!
K a t j a12 Nov 2022 15:11
Maybe something like this because of the windows:

Floor plan of a bathroom with a storage room on the left: shower, bathtub, and sink.


Or with the staggered doors if possible:

Floor plan of a bathroom with two rooms: shower, sink, toilet, and bathtub.
L
leschaf
12 Nov 2022 19:37
Thanks for the input, we will consider that! Over the past six years, we have managed well with the sit-down bathtub (110cm (43 inches)) in our small bathroom, but we have used it exclusively for bathing the children (sometimes even with three kids at once when friends were over). We definitely still need it for that purpose now, with two children. Personally, we’re not really bathtub fans. Before we moved in together, my wife also had a large bathtub, but she didn’t use it even once in three years.

Does anyone have any suggestions regarding the window questions? We would be very grateful for that 🙂
L
leschaf
10 Jan 2023 16:17
New year – a lot has happened! Although less so on the construction site 🙂

We became parents for the second time in mid-November (4 weeks early). Our daughter arrived very light but healthy, and after 2 weeks of care in the hospital, we have all been home since the beginning of December. This currently demands a lot from us, and doing any work ourselves is out of the question right now. That’s why we have now commissioned the remainder of the gutting work; the costs are very reasonable, and work is already underway.

To fully utilize the subsidy amount from BAFA, we waited until January 1st to apply for the heat pump and have now placed the order.

For the windows, we decided to lower the sill height on most of them to bring more light into the house. They will also be wooden windows with a prominent casement sash; here is a design from the architect – we think it looks great.

As can be seen below, we are initially not planning to install lift-and-slide doors but will also use casement doors for cost reasons.

Quotes from the rough and drywall contractors as well as the electrician are still pending; the missing electrician is also causing delays because without them, we cannot get temporary power for the demolition work, etc. 🙁
Tolentino10 Jan 2023 16:27
Congratulations and all the best. I hope no obstacles will be put in your way!
L
leschaf
24 Jan 2023 17:24
So, things actually moved a bit faster with the contractors.

Last week, we received two electrician quotes (one about 40% more expensive than the other) and a shell construction offer. Both match the architect’s cost estimate within +/- 1,000€ (about 1,100 USD), and for the shell builder, we even added two extra items (chimney demolition and removal of the window reveals because they are not insulated...).

Then the structural engineer came in and increased the shell builder’s offer by 10,000€ (about 11,000 USD) because significantly more support is needed than initially expected. Well, we had anticipated having to spend extra for the two additional items, so it’s painful now, but okay.

We also had a roofer on site. Unfortunately, insulating the attic and side spaces is not straightforward and definitely won’t meet the KfW standard of a 0.14 U-value. Also, he mentioned there could be issues with waterproofness concerning the photovoltaic system on the current (old) roof. He is now preparing a quote for a complete re-roofing and insulation above the rafters, so then we can decide how to insulate.

Unfortunately, the correct sizing of the heat pump depends on this, so we still haven’t been able to order it.

But: the shell builder wants to start on Monday. Finally, something is happening 🙂
F
Finch039
25 Jan 2023 08:11
leschaf schrieb:


We had a roofer visit as well. Insulating the attic and knee walls is unfortunately not that simple and definitely won’t meet the KfW requirement of a 0.14 U-value. He also mentioned there could be issues with the watertightness of the photovoltaic system on the current (old) roof. He is now preparing an offer for a complete reroofing and exterior insulation above the rafters, and then we can decide how to proceed with the insulation.

Glad to hear you’re making progress.

Regarding the roof: exterior insulation above the rafters does meet the KfW requirement, and it should make the roof very tight. Why are you hesitating? Is it because of cost, I assume? How big is the difference?