ᐅ Construction costs for terraces and similar elements in cost estimates according to DIN 276
Created on: 16 Oct 2018 15:51
P
Pyrate
First of all, hello to everyone in this great forum!
We are also future homeowners and currently have some questions about construction costs during the conceptual planning phase.
The plan is for a Bauhaus-style house with about 200 sqm (2,150 sq ft) over two floors. We now have initial designs including a cost estimate based on DIN 276.
We have generally liked the idea of having roof overhangs on the south side with covered terraces on the ground floor and balconies on the upper floor underneath. One of the concepts includes exactly this, while the other does not.
However, with the concept that includes covered outdoor areas, the costs according to the DIN 276 estimate skyrocket. The architect explained that the covered terraces and balconies are fully included in the cost estimate, specifically in the parameters of usable floor area (UFA), gross volume (GV), and gross floor area (GFA).
This means that the concept with 200 sqm (2,150 sq ft) of “indoor” space without any overhangs, terraces, or balconies is cheaper than the concept with 180 sqm (1,940 sq ft) of indoor space plus 40 sqm (430 sq ft) of covered balcony/terrace area. The UFA of the first building is 200 sqm (2,150 sq ft), while the second is 220 sqm (2,370 sq ft). Multiplied by the same construction cost index (CCI) values, the second building is more expensive even though it offers less indoor space.
My question is this: Is it really true that the cost estimate does not distinguish between fully enclosed living space and a terrace covered by a projecting roof? The latter should be significantly cheaper to build than true living space, right? Even if it is structurally connected to the main building as a cantilevered roof extension...
I would greatly appreciate your advice here.
We are also future homeowners and currently have some questions about construction costs during the conceptual planning phase.
The plan is for a Bauhaus-style house with about 200 sqm (2,150 sq ft) over two floors. We now have initial designs including a cost estimate based on DIN 276.
We have generally liked the idea of having roof overhangs on the south side with covered terraces on the ground floor and balconies on the upper floor underneath. One of the concepts includes exactly this, while the other does not.
However, with the concept that includes covered outdoor areas, the costs according to the DIN 276 estimate skyrocket. The architect explained that the covered terraces and balconies are fully included in the cost estimate, specifically in the parameters of usable floor area (UFA), gross volume (GV), and gross floor area (GFA).
This means that the concept with 200 sqm (2,150 sq ft) of “indoor” space without any overhangs, terraces, or balconies is cheaper than the concept with 180 sqm (1,940 sq ft) of indoor space plus 40 sqm (430 sq ft) of covered balcony/terrace area. The UFA of the first building is 200 sqm (2,150 sq ft), while the second is 220 sqm (2,370 sq ft). Multiplied by the same construction cost index (CCI) values, the second building is more expensive even though it offers less indoor space.
My question is this: Is it really true that the cost estimate does not distinguish between fully enclosed living space and a terrace covered by a projecting roof? The latter should be significantly cheaper to build than true living space, right? Even if it is structurally connected to the main building as a cantilevered roof extension...
I would greatly appreciate your advice here.
To clarify once again:
The south-facing side of the house is 10 m (33 feet) long, and the house consists of a ground floor (GF) and an upper floor (UF). In front of the south side, the floor slab of the GF extends about 2 m (6.5 feet) outwards, which effectively creates a 20 m² (215 sq ft) balcony for the UF. Below that, a covered terrace of 20 m² (215 sq ft) is created for the GF. Additionally, the roof of the UF (the house roof) also extends 2 m (6.5 feet) outwards, so the UF balcony is covered as well.
In total, this results in 40 m² (430 sq ft) of covered terrace. These areas are counted fully, without any reductions or applying a quarter multiplier, but 1:1 in the net usable floor area (NUF) as well as in other parameters of the cost estimation. Therefore, in the cost calculation, there is no difference whether these 40 m² are normal living space or terrace.
And of course, without any support posts—how else would it look?
Jokes aside. This is basically the point we are stumbling over: we can choose whether we prefer regular indoor space or a terrace of the same size, and it would not make any difference in the cost estimation.
The south-facing side of the house is 10 m (33 feet) long, and the house consists of a ground floor (GF) and an upper floor (UF). In front of the south side, the floor slab of the GF extends about 2 m (6.5 feet) outwards, which effectively creates a 20 m² (215 sq ft) balcony for the UF. Below that, a covered terrace of 20 m² (215 sq ft) is created for the GF. Additionally, the roof of the UF (the house roof) also extends 2 m (6.5 feet) outwards, so the UF balcony is covered as well.
In total, this results in 40 m² (430 sq ft) of covered terrace. These areas are counted fully, without any reductions or applying a quarter multiplier, but 1:1 in the net usable floor area (NUF) as well as in other parameters of the cost estimation. Therefore, in the cost calculation, there is no difference whether these 40 m² are normal living space or terrace.
And of course, without any support posts—how else would it look?
Jokes aside. This is basically the point we are stumbling over: we can choose whether we prefer regular indoor space or a terrace of the same size, and it would not make any difference in the cost estimation.
Pyrate schrieb:
Jokes aside. This is basically the point we're stumbling over: we can decide whether we prefer regular indoor space or a terrace of the same size, and it wouldn't make a difference in the cost estimate.No, not at all... You have a 20 sqm (215 sq ft) terrace on the ground floor and a 20 sqm (215 sq ft) terrace on the upper floor, both covered. And both without supports. That means you have two cantilevers, each 2 x 10 m (2 x 33 ft). This results in significantly higher structural engineering requirements (which probably make up a large part of the cost). You have 2 x 10 m (2 x 33 ft) of surface that needs waterproofing, parapets or railings, etc.
You haven’t really looked much into construction costs and how they are formed, have you?
Why don’t you give some numbers... in euros! What is the cost estimate for option 1 and what is it for option 2?
That means a solid concrete structure in the house.
Our ground floor also cantilevers 90cm (35 inches) over the basement. For this, the entire ground floor was shuttered up to the window sill height. There is also an upper floor above, so it’s quite a heavy load.
This means more time and material are required compared to regular masonry.
Our ground floor also cantilevers 90cm (35 inches) over the basement. For this, the entire ground floor was shuttered up to the window sill height. There is also an upper floor above, so it’s quite a heavy load.
This means more time and material are required compared to regular masonry.
I’m not surprised the architect’s cost estimate matches option 1.
Do you know how much a cantilevered flat roof costs?
We would have also liked to have a concrete roof overhang of 1m (3 feet) around the house. But when the general contractor said that would cost almost 20,000 euros, we quickly dropped the idea.
What I’m wondering, though, is how modest it will look in the end if you have a flat roof cantilevering 2m (6.5 feet) on the south side. I’ve never seen that before.
Could you upload some drawings so it’s easier to assess?
Do you know how much a cantilevered flat roof costs?
We would have also liked to have a concrete roof overhang of 1m (3 feet) around the house. But when the general contractor said that would cost almost 20,000 euros, we quickly dropped the idea.
What I’m wondering, though, is how modest it will look in the end if you have a flat roof cantilevering 2m (6.5 feet) on the south side. I’ve never seen that before.
Could you upload some drawings so it’s easier to assess?
Unfortunately, I don’t have any drawings to share here. At this point, it’s not so much about the appearance but more about the costs.
It’s hard to accept that, cost-wise, it doesn’t make a difference whether I convert the terrace 1:1 into regular living space or not.
The roof overhangs also provide a practical advantage as passive solar shading. Otherwise, you basically have to keep the blinds down all day. In that case, I wouldn’t need a view anyway...
It’s hard to accept that, cost-wise, it doesn’t make a difference whether I convert the terrace 1:1 into regular living space or not.
The roof overhangs also provide a practical advantage as passive solar shading. Otherwise, you basically have to keep the blinds down all day. In that case, I wouldn’t need a view anyway...
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