ᐅ Planning a Building Extension (Foundation/Load-Bearing Capacity/Alternatives)
Created on: 26 Sep 2019 13:09
P
pmuente
Hello,
I’m Peter and new here.
At the moment, I’m dealing with my eight-family house.
The house was built in 1957. Actually, it consists of two adjacent four-family houses, each with two apartments side by side and two stacked above. All the apartments are about 57m² (600 sq ft) each.
The previous owners renovated a lot over the decades, but not the roof, and it is now beyond repair.
Since the stairwell leads up to the attic, the idea came up to add another floor with four more apartments (side by side).
The city building authority approved this. Unfortunately, there are no original plans, not even in the city archives. Because of this, the structural engineer instructed to expose the foundation of the load-bearing exterior walls and the central wall in one continuous section.
And here things stand now. All the foundations are only as wide as the load-bearing walls (30cm (12 inches)) and the structural integrity is, by today’s standards, insufficient even for the existing building.
To add the additional floor, all load-bearing walls and foundations would have to be strengthened.
However, for a building of this length, the foundation reinforcement alone would reportedly cost no less than €100,000.
I don’t want to put such a strain on the old house.
Currently, neither architect nor structural engineer can offer a solution.
One idea I had was to build the apartments almost independently, using steel columns and beams above the existing structure at a height of 5.5m (18 feet). Visually, I find steel beams running along the existing building appealing, and it would decouple the weight of the new apartments from the old structure. Everyone still looks at me skeptically, but I’m searching for solutions and both the architect and structural engineer seem somewhat conservative at the moment.
I hope to find national and many other suggestions in this forum.
Thank you very much.
Peter
I’m Peter and new here.
At the moment, I’m dealing with my eight-family house.
The house was built in 1957. Actually, it consists of two adjacent four-family houses, each with two apartments side by side and two stacked above. All the apartments are about 57m² (600 sq ft) each.
The previous owners renovated a lot over the decades, but not the roof, and it is now beyond repair.
Since the stairwell leads up to the attic, the idea came up to add another floor with four more apartments (side by side).
The city building authority approved this. Unfortunately, there are no original plans, not even in the city archives. Because of this, the structural engineer instructed to expose the foundation of the load-bearing exterior walls and the central wall in one continuous section.
And here things stand now. All the foundations are only as wide as the load-bearing walls (30cm (12 inches)) and the structural integrity is, by today’s standards, insufficient even for the existing building.
To add the additional floor, all load-bearing walls and foundations would have to be strengthened.
However, for a building of this length, the foundation reinforcement alone would reportedly cost no less than €100,000.
I don’t want to put such a strain on the old house.
Currently, neither architect nor structural engineer can offer a solution.
One idea I had was to build the apartments almost independently, using steel columns and beams above the existing structure at a height of 5.5m (18 feet). Visually, I find steel beams running along the existing building appealing, and it would decouple the weight of the new apartments from the old structure. Everyone still looks at me skeptically, but I’m searching for solutions and both the architect and structural engineer seem somewhat conservative at the moment.
I hope to find national and many other suggestions in this forum.
Thank you very much.
Peter
4 x 57m² (4 x 613ft²) new construction plus costs for unknown demolition, reinforcement, and other renovation work on the existing structure will likely amount to at least €500,000 - €600,000 including incidental building costs (gross). However, without knowledge of the specific construction task and the structural conditions, such estimates remain purely speculative.
N
nix zu schwör13 Oct 2019 12:00Alternatively, it might be a good idea to consult another structural engineer.
With existing buildings, this is quite common until you find the right one.
We do a lot of planning in the Rhine-Main area, where adding additional floors is often the only solution.
A steel framework can be located either inside or outside the existing building envelope. Nowadays, it is often requested that all interior walls in an existing building be removed.
The existing foundations may possibly be completely disregarded.
This is no dream at all—how else could residential units be implemented on a warehouse roof? Even timber constructions have their weight.
It is unlikely to be a social housing project.
Furthermore, the upper building closure should have complied with the Energy Saving Ordinance since 2015.
With existing buildings, this is quite common until you find the right one.
We do a lot of planning in the Rhine-Main area, where adding additional floors is often the only solution.
A steel framework can be located either inside or outside the existing building envelope. Nowadays, it is often requested that all interior walls in an existing building be removed.
The existing foundations may possibly be completely disregarded.
This is no dream at all—how else could residential units be implemented on a warehouse roof? Even timber constructions have their weight.
It is unlikely to be a social housing project.
Furthermore, the upper building closure should have complied with the Energy Saving Ordinance since 2015.
nichts zu schwör schrieb:
The existing foundations might possibly be completely irrelevant. Those of the steel frame would need to be quite close by.
nichts zu schwör schrieb:
It’s unlikely that any social housing is planned. Which premium tenants do you think would be attracted to 57 sqm (about 615 sq ft) in the foothills region?
https://www.instagram.com/11antgmxde/
https://www.linkedin.com/company/bauen-jetzt/
N
nordanney13 Oct 2019 20:09pmuente schrieb:
Well, Euskirchen is definitely in high demand.In high demand? Well, then rents would be higher. On average, you’re paying about €7.50 (around $8) in your area; there’s no way to get more than €8.50 (around $9) rent for a brand new building. Now calculate your investment realistically.
Four units of 57 m² (about 613 sq ft) at €8 rent bring in €22,000 (about $24,800) per year.
If we roughly estimate €2,000 (about $2,250) per m² for the construction costs of the additional storey, that rounds up to a lean €500,000 (about $565,000) including incidental building costs. That results in a gross yield of 4.4% BEFORE management and taxes. That’s total nonsense. To break even reasonably well, you’d need at least 6%. With that, your budget would shrink to about €370,000 (about $418,000), which means only €1,622 (about $1,835) per m² living space for a technically demanding solution. And that won’t work.
If the rest of the building and the location aren’t comparable to new construction standards, you won’t get top rents, and your investment will increasingly lose value...
By now, I’m charging 500€ (about $540) per month excluding utilities for each new rental, and people are really lining up. Maybe I should build a third building?
The house was built in 1957, partially insulated about 15 years ago, and fitted with a central heating system.
When there are no curtains on the windows, strangers ring the tenants’ doorbells asking if the apartment is available. For a newly built, first-time rental, I expect even 9€ (about $9.70) or more per square meter.
I actually don’t consider it inexpensive either, but apartments of this size are almost non-existent on the market. You almost tend to build five units of 45 square meters (about 484 square feet) each, since even more people would stand in line.
But the financial calculation is my problem.
Since I urgently need a new roof, having a roof without added value would probably be an even worse investment—or am I mistaken?
And by roof, I actually mean everything, not just tiles and insulation.
The house was built in 1957, partially insulated about 15 years ago, and fitted with a central heating system.
When there are no curtains on the windows, strangers ring the tenants’ doorbells asking if the apartment is available. For a newly built, first-time rental, I expect even 9€ (about $9.70) or more per square meter.
I actually don’t consider it inexpensive either, but apartments of this size are almost non-existent on the market. You almost tend to build five units of 45 square meters (about 484 square feet) each, since even more people would stand in line.
But the financial calculation is my problem.
Since I urgently need a new roof, having a roof without added value would probably be an even worse investment—or am I mistaken?
And by roof, I actually mean everything, not just tiles and insulation.
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