Hello everyone,
After my "plan" for a new build has become very uncertain due to various factors, I am now planning to extend my existing house and am trying to get a rough overview of the costs involved.
The existing house has a ground floor of approximately 90m² (970 sq ft) of living space and an extension of around 70m² (750 sq ft). My parents live on the ground floor and will remain there (in case anyone thinks of suggesting "just swap"). The older part of the house has a basement. The upper floor of the older building basically contains the same apartment (I live there).
The extension was designed 20 years ago to allow for an easy vertical extension in terms of structural engineering. So, structurally it’s no problem. The roof just needs to be removed, the ring beam at the rear part raised by about 1.5 meters (5 feet), and a suitable intermediate floor installed. No additional support columns or similar are necessary.
The new extension is planned to include a bathroom, kitchen, living/dining room, and a balcony. Possibly a bedroom instead of the kitchen, though that would mean relocating the kitchen to a room in the old building without existing connections—and I would prefer not to have to tear up the entire old building. The new bathroom could be connected to the existing plumbing with a core drilling, which would minimize demolition work.
I asked an acquaintance with architectural "skills" what kind of costs I should expect. He said an extension is basically like a new build, and I should expect roughly €1800 per m² (about $190 per sq ft) of living space. Does that seem realistic?
How would you roughly estimate the costs for the following items (my amateur estimates in parentheses):
Ring beam masonry (€2,000 with own work)
Installing intermediate floor (€20,000)
New masonry work (€10,000 with own work)
Windows (€20,000)
Roof including facade (€30,000)
Sanitary installations including bathroom and underfloor heating (€20,000)
Building services (electricity, network, etc.) (€8,000 with own work)
Flooring, walls, wood ceiling (€15,000 with own work)
Additional costs (€15,000)
Total: €140,000
Does this sound realistic? Or is something way off from actual costs?
After my "plan" for a new build has become very uncertain due to various factors, I am now planning to extend my existing house and am trying to get a rough overview of the costs involved.
The existing house has a ground floor of approximately 90m² (970 sq ft) of living space and an extension of around 70m² (750 sq ft). My parents live on the ground floor and will remain there (in case anyone thinks of suggesting "just swap"). The older part of the house has a basement. The upper floor of the older building basically contains the same apartment (I live there).
The extension was designed 20 years ago to allow for an easy vertical extension in terms of structural engineering. So, structurally it’s no problem. The roof just needs to be removed, the ring beam at the rear part raised by about 1.5 meters (5 feet), and a suitable intermediate floor installed. No additional support columns or similar are necessary.
The new extension is planned to include a bathroom, kitchen, living/dining room, and a balcony. Possibly a bedroom instead of the kitchen, though that would mean relocating the kitchen to a room in the old building without existing connections—and I would prefer not to have to tear up the entire old building. The new bathroom could be connected to the existing plumbing with a core drilling, which would minimize demolition work.
I asked an acquaintance with architectural "skills" what kind of costs I should expect. He said an extension is basically like a new build, and I should expect roughly €1800 per m² (about $190 per sq ft) of living space. Does that seem realistic?
How would you roughly estimate the costs for the following items (my amateur estimates in parentheses):
Ring beam masonry (€2,000 with own work)
Installing intermediate floor (€20,000)
New masonry work (€10,000 with own work)
Windows (€20,000)
Roof including facade (€30,000)
Sanitary installations including bathroom and underfloor heating (€20,000)
Building services (electricity, network, etc.) (€8,000 with own work)
Flooring, walls, wood ceiling (€15,000 with own work)
Additional costs (€15,000)
Total: €140,000
Does this sound realistic? Or is something way off from actual costs?
Hello,
I have received some additional information:
The building authority responsible has approved the project. The structural engineering of the existing extension allows for adding an additional floor without any issues.
The roofer visited and mentioned that the pitch of the new roof won’t allow for a tiled roof anymore. We will need to switch to what he called a sandwich roof – this means that the existing rafters likely can no longer be used significantly. He also said that an additional concrete ceiling will be required on the extended floor, which won't make much difference cost-wise because it would replace insulation anyway. Overall, he estimates about €25,000–30,000 (plus insulation of the facade, which is not included in that price).
The heating engineer came by and said the existing heating system can be used without problems and can easily supply underfloor heating for the new extension. We can install the underfloor heating panels ourselves. He estimated the new bathroom, including my desired fixtures, at approximately €12,000–13,000 – this includes lighting, a stretch ceiling, and a towel radiator. What is still missing are the tiles, which we will also install ourselves. The cost for the underfloor heating should be around €7,000 – we paid about the same for exactly this size 1.5 years ago in the existing extension, so it shouldn't change much. The remaining installations (drainage, supply lines, etc.) he estimated at a maximum of €5,000 – so with €25,000, I think I am on the safe side here.
The flooring contractor has given me a quote of about €7,000 for dry screed panels on the underfloor heating, impact sound insulation underneath, a vapor barrier, and so on, as well as linoleum flooring throughout the extension except the bathroom. That sounds reasonable so far.
Questions:
1. What should I expect for the cost of demolition? Or who should I ask about that? Also a roofer?
2. What costs should I expect for masonry work? Both for raising the ring beam to one level and for the masonry of the extension?
3. How much does a foundation slab cost? Do I really need two of them? Who should I ask about that?
4. What is a realistic estimate for windows? I think one nice large window in the bathroom, one in the bedroom, and a large glass sliding door at least 2–3m (6.5–10 feet) wide to the balcony should be sufficient, right?
Best regards,
Xorrhal
I have received some additional information:
The building authority responsible has approved the project. The structural engineering of the existing extension allows for adding an additional floor without any issues.
The roofer visited and mentioned that the pitch of the new roof won’t allow for a tiled roof anymore. We will need to switch to what he called a sandwich roof – this means that the existing rafters likely can no longer be used significantly. He also said that an additional concrete ceiling will be required on the extended floor, which won't make much difference cost-wise because it would replace insulation anyway. Overall, he estimates about €25,000–30,000 (plus insulation of the facade, which is not included in that price).
The heating engineer came by and said the existing heating system can be used without problems and can easily supply underfloor heating for the new extension. We can install the underfloor heating panels ourselves. He estimated the new bathroom, including my desired fixtures, at approximately €12,000–13,000 – this includes lighting, a stretch ceiling, and a towel radiator. What is still missing are the tiles, which we will also install ourselves. The cost for the underfloor heating should be around €7,000 – we paid about the same for exactly this size 1.5 years ago in the existing extension, so it shouldn't change much. The remaining installations (drainage, supply lines, etc.) he estimated at a maximum of €5,000 – so with €25,000, I think I am on the safe side here.
The flooring contractor has given me a quote of about €7,000 for dry screed panels on the underfloor heating, impact sound insulation underneath, a vapor barrier, and so on, as well as linoleum flooring throughout the extension except the bathroom. That sounds reasonable so far.
Questions:
1. What should I expect for the cost of demolition? Or who should I ask about that? Also a roofer?
2. What costs should I expect for masonry work? Both for raising the ring beam to one level and for the masonry of the extension?
3. How much does a foundation slab cost? Do I really need two of them? Who should I ask about that?
4. What is a realistic estimate for windows? I think one nice large window in the bathroom, one in the bedroom, and a large glass sliding door at least 2–3m (6.5–10 feet) wide to the balcony should be sufficient, right?
Best regards,
Xorrhal
B
Bauexperte20 Jan 2016 12:28Hello,
If he means a pitched or double-pitched roof under 23° (degrees), he is correct.
So, that’s what he means...
While I understand you want answers – no one here can provide them, as the crystal balls are out of order.
You want to carry out much of this as a self-builder, so it makes sense to hire an architect (which you will need anyway) and contract the individual trades separately. Make sure to choose an architect experienced in renovation of existing buildings. Walk through the current structure with them, discuss the construction measures, and they will tell you what needs to be done and give you a cost estimate. They can also advise where self-building is sensible and what on the existing structure must be altered.
Regarding points 1 to 4, there are many unknowns since no design or thermal insulation calculations exist yet. Until then, a lot can change—or, as we say here in the Rhineland, there’s still a lot of water flowing up the Rhine. I can’t say what demolition will cost, not even roughly. For that, I’d need the documents on the existing building, know the site conditions, materials used, etc. I could imagine there might be potential for self-building here—if the scaffolder has been involved on site.
Regards, Bauexperte
Xorrhal schrieb:
So we have to switch to a – as he called it – sandwich roof, which means that the existing roof structure can probably no longer be used much.
If he means a pitched or double-pitched roof under 23° (degrees), he is correct.
Xorrhal schrieb:
He also said that an additional concrete ceiling would need to be added on the new story, which wouldn’t make much of a cost difference since it would replace insulation.
So, that’s what he means...
Xorrhal schrieb:
1. What should I budget for the demolition? Or who do you ask for that? A roofer as well?
2. What should I budget for the masonry? Both for raising the ring beam to one level and for the masonry work on the extension?
3. How much does a slab foundation cost? Do I really need two of them? Who do I ask?
4. What’s a rough estimate for the windows? I think a nice large one in the bathroom, one in the bedroom, and a large glass sliding door at least 2 to 3 m (6 to 10 feet) wide leading to the balcony should be sufficient, right?
While I understand you want answers – no one here can provide them, as the crystal balls are out of order.
You want to carry out much of this as a self-builder, so it makes sense to hire an architect (which you will need anyway) and contract the individual trades separately. Make sure to choose an architect experienced in renovation of existing buildings. Walk through the current structure with them, discuss the construction measures, and they will tell you what needs to be done and give you a cost estimate. They can also advise where self-building is sensible and what on the existing structure must be altered.
Regarding points 1 to 4, there are many unknowns since no design or thermal insulation calculations exist yet. Until then, a lot can change—or, as we say here in the Rhineland, there’s still a lot of water flowing up the Rhine. I can’t say what demolition will cost, not even roughly. For that, I’d need the documents on the existing building, know the site conditions, materials used, etc. I could imagine there might be potential for self-building here—if the scaffolder has been involved on site.
Regards, Bauexperte
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