Hello 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.
S
schornstein7 May 2010 20:40Our basement was included in the contract. I don’t know which manufacturer it was. We installed the empty conduits ourselves. The shell construction contractor told us the date when the ceiling would be installed, then you have a few days to complete the work. However, we had to hurry a lot because the concrete had to be poured the next day.
B
BumbleBee21 May 2010 00:15Well
I don’t mean to offend anyone, but what is written here only covers half of it. Sure, there are more pros and cons than can be listed here. If you’re building something to last, then do it properly, otherwise you’ll have to invest a lot of money later on. I suggest using concrete C20/25.
1. Foundation: C20/25 concrete with 0-32 mm (0-1.25 inches) aggregate size, not waterproof concrete since it’s an exterior component.
2. Floor slab: also C20/25 concrete with 0-16 mm (0-0.6 inches) aggregate size, waterproof concrete with joint tape (horizontal), for example pentaplex or similar.
3. Concrete walls: cast-in-place, not precast elements, because too many joints are created otherwise, which are weak points for water. Also C20/25 with 0-16 mm (0-0.6 inches) aggregate.
4. Ceiling: precast slab elements can be used and then poured with in-situ concrete. The structural engineer must decide on the type and consistency of the concrete as it depends on the exposure class, mechanical or natural weather influences, soil type and condition. Electrical conduits can be installed in the walls or ceiling beforehand. If the basement wall can’t be poured all at once, a joint tape must be installed (vertical).
5. Insulation: best to clean the surface well and form a fillet at the base. Then apply bitumen primer, let it dry, and afterwards apply a thick coating (approximately 3 mm (0.1 inches)), let it dry for 2-3 days. An 80 mm (3 inches) Styrodur insulation is sufficient because thermal transmittance can never be reduced to zero, not even with 2 meters (6.5 feet) of insulation.
6. Protection for the insulation: best to use a dimpled membrane to prevent damage from stones.
7. Windows: no problem, you can make a large light well; these are available in many sizes.
8. Drainage: very important. Best to lay a geotextile around the floor slab, then 20 cm (8 inches) of rolled gravel above, install the drainage pipes and inspection chambers, then cover again with 20 cm (8 inches) of rolled gravel and another geotextile on top so that soil does not mix with the gravel and clog the drainage.
9. Then backfill and compact very well, ideally every 30-50 cm (12-20 inches) with a jumping jack compactor or vibrating plate.
I have to say this costs more but it’s a very good solution if you want to.
Regards, BumbleBee
If you want, I can list the pros and cons compared to concrete and stone, no problem.
I don’t mean to offend anyone, but what is written here only covers half of it. Sure, there are more pros and cons than can be listed here. If you’re building something to last, then do it properly, otherwise you’ll have to invest a lot of money later on. I suggest using concrete C20/25.
1. Foundation: C20/25 concrete with 0-32 mm (0-1.25 inches) aggregate size, not waterproof concrete since it’s an exterior component.
2. Floor slab: also C20/25 concrete with 0-16 mm (0-0.6 inches) aggregate size, waterproof concrete with joint tape (horizontal), for example pentaplex or similar.
3. Concrete walls: cast-in-place, not precast elements, because too many joints are created otherwise, which are weak points for water. Also C20/25 with 0-16 mm (0-0.6 inches) aggregate.
4. Ceiling: precast slab elements can be used and then poured with in-situ concrete. The structural engineer must decide on the type and consistency of the concrete as it depends on the exposure class, mechanical or natural weather influences, soil type and condition. Electrical conduits can be installed in the walls or ceiling beforehand. If the basement wall can’t be poured all at once, a joint tape must be installed (vertical).
5. Insulation: best to clean the surface well and form a fillet at the base. Then apply bitumen primer, let it dry, and afterwards apply a thick coating (approximately 3 mm (0.1 inches)), let it dry for 2-3 days. An 80 mm (3 inches) Styrodur insulation is sufficient because thermal transmittance can never be reduced to zero, not even with 2 meters (6.5 feet) of insulation.
6. Protection for the insulation: best to use a dimpled membrane to prevent damage from stones.
7. Windows: no problem, you can make a large light well; these are available in many sizes.
8. Drainage: very important. Best to lay a geotextile around the floor slab, then 20 cm (8 inches) of rolled gravel above, install the drainage pipes and inspection chambers, then cover again with 20 cm (8 inches) of rolled gravel and another geotextile on top so that soil does not mix with the gravel and clog the drainage.
9. Then backfill and compact very well, ideally every 30-50 cm (12-20 inches) with a jumping jack compactor or vibrating plate.
I have to say this costs more but it’s a very good solution if you want to.
Regards, BumbleBee
If you want, I can list the pros and cons compared to concrete and stone, no problem.
haeuslebauer21 May 2010 12:33Pros and Cons of Masonry or Concrete Basements
Hello BumbleBee,
thank you for your opinion regarding concrete basements. It would be very interesting to learn about the pros and cons you have.
BumbleBee schrieb:
I have to say, it does cost more, but it’s a very good solution. If you want, I can list the pros and cons compared to concrete and stone, no problem.
Hello BumbleBee,
thank you for your opinion regarding concrete basements. It would be very interesting to learn about the pros and cons you have.
I have done some more research and now understand that building a basement for an energy-efficient house has to be done quite differently compared to a standard house. Is that correct, and if so, what exactly needs to be considered? Does this involve higher costs, and if yes, how much more in percentage terms?
Thank you in advance!
Thank you in advance!
haeuslebauer5 Jun 2010 08:58Which Basement?
Hello Bambus,
To give you an accurate answer, you should know which energy efficiency class you want to achieve with your house/basement. As you probably know, there are different classes such as 85, 70, 50, or the so-called passive house. The better the efficiency class, the better the loan conditions from KfW. However, the lower the heating demand, the more expensive the structural measures can be!
Also important is how you plan to use the basement. What do you intend to do with your basement later on? Should it be designed as a utility basement or a living basement? Are you possibly planning a granny flat or separate apartment with its own entrance (e.g., an outside staircase)? Should you install thermal insulation windows with triple glazing and roller shutter boxes instead of standard basement windows and light wells?
At the same time, you should also consider the basement height, electrical and plumbing installations. Will you possibly need a wastewater lifting station? What is your plot like? Is it on a slope or flat? How is the soil condition and groundwater level?
As mentioned earlier, depending on the usage and level of planning, building a basement can cost more or less.
Your question is unfortunately too general to provide a precise answer.
bambus schrieb:
So, I’ve done some more reading and now understand that building a basement for an energy-efficient house is quite different from building one for a standard house. Is that correct, and if so, what exactly should be considered? Does it involve higher costs? How much more, percentage-wise?
Thanks in advance!
Hello Bambus,
To give you an accurate answer, you should know which energy efficiency class you want to achieve with your house/basement. As you probably know, there are different classes such as 85, 70, 50, or the so-called passive house. The better the efficiency class, the better the loan conditions from KfW. However, the lower the heating demand, the more expensive the structural measures can be!
Also important is how you plan to use the basement. What do you intend to do with your basement later on? Should it be designed as a utility basement or a living basement? Are you possibly planning a granny flat or separate apartment with its own entrance (e.g., an outside staircase)? Should you install thermal insulation windows with triple glazing and roller shutter boxes instead of standard basement windows and light wells?
At the same time, you should also consider the basement height, electrical and plumbing installations. Will you possibly need a wastewater lifting station? What is your plot like? Is it on a slope or flat? How is the soil condition and groundwater level?
As mentioned earlier, depending on the usage and level of planning, building a basement can cost more or less.
Your question is unfortunately too general to provide a precise answer.
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