haeuslebauer6 May 2010 09:43Hello everyone,
We are currently in the planning phase for our basement.
After reviewing several house offers, we have two options for building the basement:
1.) Constructing the basement with 36.5 cm (14 inches) perforated bricks
2.) A precast concrete basement or a basement made of 24.5 cm (10 inches) concrete
Both are planned to be built on an appropriate concrete slab. The site is completely level, and the local authorities have informed us that, due to soil conditions and the groundwater level, it is not necessary to plan a basement using waterproof concrete or a “white tank” system. The basement should have a height of 2.80 m (9 ft 2 in) (rough construction dimension) because it will be used as a separate apartment. Mostly standard windows will be installed. The basement will have a separate entrance. All necessary installations (electrical, water, heating) are planned to be installed flush with the walls.
After several discussions with builders, we have not yet made a final decision. However, both options have many pros and cons!
Some say that a basement made of perforated bricks performs better in terms of indoor climate than a concrete basement. Others argue that the difference compared to concrete walls is hardly noticeable. The concrete basement is said to be more resistant and waterproof against potential moisture but needs to be insulated separately with 120 mm (5 inches) rigid foam boards for thermal insulation.
For the basement with perforated bricks, a polymer-modified bitumen thick coating (at least 3 mm (0.1 inches)) would address the same issue!
Because of the wall thickness, no separate insulation is necessary.
Now our question is: Which basement option is better?
Who can help us with this?
Thank you very much in advance.
We are currently in the planning phase for our basement.
After reviewing several house offers, we have two options for building the basement:
1.) Constructing the basement with 36.5 cm (14 inches) perforated bricks
2.) A precast concrete basement or a basement made of 24.5 cm (10 inches) concrete
Both are planned to be built on an appropriate concrete slab. The site is completely level, and the local authorities have informed us that, due to soil conditions and the groundwater level, it is not necessary to plan a basement using waterproof concrete or a “white tank” system. The basement should have a height of 2.80 m (9 ft 2 in) (rough construction dimension) because it will be used as a separate apartment. Mostly standard windows will be installed. The basement will have a separate entrance. All necessary installations (electrical, water, heating) are planned to be installed flush with the walls.
After several discussions with builders, we have not yet made a final decision. However, both options have many pros and cons!
Some say that a basement made of perforated bricks performs better in terms of indoor climate than a concrete basement. Others argue that the difference compared to concrete walls is hardly noticeable. The concrete basement is said to be more resistant and waterproof against potential moisture but needs to be insulated separately with 120 mm (5 inches) rigid foam boards for thermal insulation.
For the basement with perforated bricks, a polymer-modified bitumen thick coating (at least 3 mm (0.1 inches)) would address the same issue!
Because of the wall thickness, no separate insulation is necessary.
Now our question is: Which basement option is better?
Who can help us with this?
Thank you very much in advance.
6
6Richtige6 May 2010 13:25Hello Home Builder,
you’ve been active in the forum for quite some time now, and then this:
Of course, you have this confirmation in writing from the municipality, and they will cover any potential costs for pumps and the waterproof shell? So: first get a soil survey done.
Why build a basement if the plot is level? Have you included the disposal costs for the excess soil? Those can easily reach 10,000 euros (about $11,000 US).
Regarding the question itself: concrete is more resistant to moisture and can be constructed quickly and accurately. Chasing channels for electrical wiring won’t be necessary, so plan everything in advance and have it prefabricated at the factory. The walls are smooth from the formwork and can be painted or wallpapered directly.
How deep do you want to go underground, and how will light reach the granny flat? I wouldn’t want to live there without floor-to-ceiling windows.
Cost-wise, this will be a real challenge. Just an external staircase with an entrance door can easily cost 5,000 euros (about $5,500 US). Overall, you can expect the basement to cost about 50% of the house’s construction costs. So don’t be surprised if the whole thing ends up costing 70,000–80,000 euros (about $77,000–88,000 US).
you’ve been active in the forum for quite some time now, and then this:
The plot is completely level, and we were informed by the municipality that, due to the soil conditions and groundwater level, it is not necessary to plan a basement using waterproof concrete or a waterproof structural shell (white tank).
Of course, you have this confirmation in writing from the municipality, and they will cover any potential costs for pumps and the waterproof shell? So: first get a soil survey done.
Why build a basement if the plot is level? Have you included the disposal costs for the excess soil? Those can easily reach 10,000 euros (about $11,000 US).
Regarding the question itself: concrete is more resistant to moisture and can be constructed quickly and accurately. Chasing channels for electrical wiring won’t be necessary, so plan everything in advance and have it prefabricated at the factory. The walls are smooth from the formwork and can be painted or wallpapered directly.
How deep do you want to go underground, and how will light reach the granny flat? I wouldn’t want to live there without floor-to-ceiling windows.
Cost-wise, this will be a real challenge. Just an external staircase with an entrance door can easily cost 5,000 euros (about $5,500 US). Overall, you can expect the basement to cost about 50% of the house’s construction costs. So don’t be surprised if the whole thing ends up costing 70,000–80,000 euros (about $77,000–88,000 US).
haeuslebauer6 May 2010 13:58Basement Details
Hello 6Richtige,
thank you again for your input. We have learned from the InovaHaus case. The municipality commissioned a soil report for the new development area, including our building plot. This seems to be common practice in the region. Based on this report, we were informed that a waterproof concrete basement (WU basement) is not necessary.
Of course, I am not a geologist, and I don’t know what will happen in the next 40 years. But the soil report only represents a snapshot in time. The houses in this new development area are partly built with masonry (Poroton) and partly with precast concrete elements. Both neighbors are very satisfied with the respective basements they have.
Regarding the windows, even though this was not asked, these are standard living space windows, not basement windows! There is only one typical basement window, as it is located below the terrace.
By a level plot, I mean no slope! The costs for excavation and earthworks have already been determined. The basement depth is about 180 cm (70 inches). This ensures good daylight access (southwest side). Also, only my son will be going down there!
The outdoor staircase and separate entrance were also previously calculated from a cost perspective. Obviously, this will not be a “normal” basement.
Our question now is: which is better, a masonry basement or a precast concrete basement?
Your points regarding the wall surfaces are valid. However, if we want to do something different in a few years, like installing new wiring etc., there could be complications! For a masonry basement, additional chases can be cut relatively easily.
Hello 6Richtige,
thank you again for your input. We have learned from the InovaHaus case. The municipality commissioned a soil report for the new development area, including our building plot. This seems to be common practice in the region. Based on this report, we were informed that a waterproof concrete basement (WU basement) is not necessary.
Of course, I am not a geologist, and I don’t know what will happen in the next 40 years. But the soil report only represents a snapshot in time. The houses in this new development area are partly built with masonry (Poroton) and partly with precast concrete elements. Both neighbors are very satisfied with the respective basements they have.
Regarding the windows, even though this was not asked, these are standard living space windows, not basement windows! There is only one typical basement window, as it is located below the terrace.
By a level plot, I mean no slope! The costs for excavation and earthworks have already been determined. The basement depth is about 180 cm (70 inches). This ensures good daylight access (southwest side). Also, only my son will be going down there!
The outdoor staircase and separate entrance were also previously calculated from a cost perspective. Obviously, this will not be a “normal” basement.
Our question now is: which is better, a masonry basement or a precast concrete basement?
Your points regarding the wall surfaces are valid. However, if we want to do something different in a few years, like installing new wiring etc., there could be complications! For a masonry basement, additional chases can be cut relatively easily.
6
6Richtige6 May 2010 14:08Hmm, 1 meter (3 feet) above ground level? No issues expected with the eave/ridge height? You could possibly spread the excavation soil on the property, which might create a steeper path to the house or garage, depending on how close the building is. If you plan to chase out channels later, go with a masonry basement and a black tank waterproofing—it’s better to be safe.
S
schornstein7 May 2010 20:03Hello, home builders
All our acquaintances who have built basements from stone have had problems with water. In these cases, there was no groundwater present. In one case, it was due to rainwater pipes; in another case, it was a neighbor who simply let rainwater seep into the ground (great!). They then had to excavate again and fix the problems.
Regarding drilling into concrete. We have a concrete basement and did not want the installation exposed on the surface. We installed empty conduits in the basement ceiling before the concrete was poured. Now the conduits are embedded in the concrete, and the pipes can be routed freely. If you think ahead a little about what might be needed, you can manage the issue well.
All our acquaintances who have built basements from stone have had problems with water. In these cases, there was no groundwater present. In one case, it was due to rainwater pipes; in another case, it was a neighbor who simply let rainwater seep into the ground (great!). They then had to excavate again and fix the problems.
Regarding drilling into concrete. We have a concrete basement and did not want the installation exposed on the surface. We installed empty conduits in the basement ceiling before the concrete was poured. Now the conduits are embedded in the concrete, and the pipes can be routed freely. If you think ahead a little about what might be needed, you can manage the issue well.
haeuslebauer7 May 2010 20:07Concrete Basement
Hello Schornstein,
thank you very much for the information.
Did you contract the basement as a separate trade, or was it part of the overall fixed-price contract with your builder?
Which basement manufacturer did you use?
Hello Schornstein,
thank you very much for the information.
Did you contract the basement as a separate trade, or was it part of the overall fixed-price contract with your builder?
Which basement manufacturer did you use?
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