ᐅ Building Without a Ventilation System Using Porous Clay Blocks?

Hello Shism,

did you build with a window rebate ventilation + exhaust system and can you tell me more about it?

Regards, Fabian

o.s. schrieb:

I’m not an expert, but next year I’m starting a house construction project with a general contractor and have asked myself similar questions. A small tip: besides hollow bricks filled with perlite, the same manufacturers (Schlagmann, Wienerberger & Co., brand name Poroton) also offer bricks filled with mineral wool, which have a U-value of 0.08 and are significantly cheaper.
:

These cost noticeably more accordingly; just compare prices yourself (marketing ploy + rip-off).

This Rockwool stuff fell apart in my test setup in the basement. I wouldn’t use such a material. I’d rather build onto the 50 cm (20 inch) masonry with wood fiber mats plus mesh and a special plaster?

o.s. schrieb:

With today’s standard wall thickness of 36.5 cm (14.5 inches) and a U-value of 0.07 or 0.08, you will probably just barely make it or not at all. They will likely recommend at least a wall thickness of 42.5 or 49 cm (17 or 19 inches). For bricks, the material cost is almost proportional to wall thickness, so you should expect several thousand euros in additional costs. :

That is incorrect because the mineral wool-filled brick is noticeably more expensive than a comparable 49 cm (19 inch) solid brick without filling with compressive strength class 8.

The mineral wool-filled brick has a higher compressive strength, and you’ll probably have to heat just as much with the 0.08 U-value as with a 50 cm (20 inch) solid brick that has a lab-measured U-value of 0.15. In the end, whether you burn 2 tons or 3 tons of pellets doesn’t really matter and won’t make a difference if you build about 30% cheaper and invest the rest in beech wood.

o.s. schrieb:

Additionally, with the same living area, the planner will have to increase the size of the foundation slab and the roof (roof structure, roof tiles, etc.) accordingly, and you will usually be charged based on the increased external dimensions. A thicker wall (36.5 vs. 49 cm / 14.5 vs. 19 inches) leads to an increase in the foundation slab area by 5 square meters (54 square feet) in a 10x10 meter (33x33 foot) house. Assume that the cost for these extra 5 square meters is roughly equivalent to 5 square meters more living space per floor, i.e., 10 square meters (108 square feet) in total. How much does 10 square meters more cost with your house planner/general contractor?:

10 m² (108 ft²) costs about 570 euros more for the foundation slab, roughly 270 euros more for the reinforcement, and about 50 euros more for the 0.4 m³ (14 cubic feet) concrete. The additional work for the roof is just around 600 euros. Alternatively, you could manage with 20 cm (8 inch) less internal space—if you spend all year inside the house, something is already wrong with you. People who spend a lot of time outdoors are usually tired in the evening and fall asleep quickly. In retirement, the house will likely be sold anyway, as an apartment is often more practical. Therefore, a house is just a temporary overnight place—nothing more. The terrace area compensates for much of this, like an added sunroom.

o.s. schrieb:

My concern: KfW 40 is a big financial challenge for a traditional brick-on-brick house. The subsidy you receive from the KfW bank for the KfW 40 standard will never compensate for your additional investment, even when considering the energy savings and energy price increases. So why choose KfW 40?:

Building without KfW standards is cheaper anyway. The only catch is the 2016 Energy Saving Ordinance, which imposes requirements that hardly bring any effective benefit (overall balance). What’s the use of saving 1 euro per square meter per year if you have to invest 200 times that amount, ending up with only a small saving that comes with a risk of mold?

You have to keep your expectations realistic. When building abroad, you don’t have to deal with all this energy saving regulation nonsense. It’s mainly a German problem. Go to France—they don’t care. Sure, they insulate, but with reasonable dimensions.

o.s. schrieb:

Yes. Every currently built house must meet legal requirements and be airtight (blower door test). This means you will probably ventilate much more via the windows than in your current dwelling. No one can forbid that.:

The blower door test is also tricky when people cut out the rubber seals at the top edge of windows just to get a more comfortable indoor climate—or when they cut the forced ventilation slots in the roller shutter boxes or windows.

You can also over-insulate yourself to death.

Go to Holland/Amsterdam and ask local project planners what they think about ventilation systems. The trend there is clearly away from ventilation systems because they make people sick. They used to install German technology, but today only about a third of builders install ventilation systems—that’s the current situation in the Netherlands.

My neighbor also has a problem with the ventilation system. When the neighboring farmer sprays his fields, the whole house smells like cow manure, even with filter technology.

Moreover, all the ducts get heavily contaminated over time, and the kids inhale the dirt—no wonder more and more asthmatics are around...

Bauexperte schrieb:

If you present your personal opinion for discussion, you should not claim it as fact. What you are sharing here is, at best, ill-considered—and therefore, for inexperienced building amateurs, dangerously misleading.

This is a plan tailored to a specific life situation; you copied the views from the homepage’s entry page in the single-family house section. These views are an example of a cube-shaped design.

With all due respect, Ms. Schenk,
from a building physics perspective, flat roofs with their depressions are structural botches, flawed even in the planning stage, and they cause problems.
When water gets underneath the bitumen membranes, you only notice the damage much later, when frost causes the concrete panels to crack.
If you had personal experience with these types of building defects, you would not return to such a amateurish design; my father could tell stories about this, due to poor advice.

Bauexperte schrieb:

Many of your so-called “old masters” produced this dangerous nonsense. By the way, just like their “estimates” of the heating energy demand for a single-family home. I know plenty of them and have “benefited” from considerable unnecessary additional work because of them. Recently, one of your old “masters” decided on short notice to install a heating unit with 3 kW higher output—just to be safe. Apart from the fact that it was completely unnecessary—the heating load calculation confirms the installed unit—it would have cost my clients an extra 5–6 thousand euros. So much for the “old masters.” .

You should never have a heating system designed by a questionable heating contractor but by a proper heating engineer, because you can hold them accountable if they size the boiler too large or too small.
If the contractor goes bankrupt, there’s nothing to claim anymore, including expert witness costs.

Bauexperte schrieb:

Here is a commentary on the flat roof guideline for interested building amateurs:

“Since October 2008, the new flat roof guideline has been mandatory and has undergone many significant changes compared to the old version from September 2003, for example regarding its scope, rules for waterproofing, materials, etc. It is basically aligned with DIN 18531 for non-occupied roofs.”

I still maintain that every flat roof construction is a botch and will remain so. Why did the local municipality replace the school’s flat roof with a hip roof after 30 years?
Because sand was falling from the ceiling? No, because the ceilings were all damp—where else should the water go during heavy rain?
Building physics: how do you expect to drain thousands of liters of water through a 100 mm (4 inch) pipe?

Bauexperte schrieb:

If the builder uses Douglas fir instead of spruce and maintains the facade properly, this claim falls flat. But—back to you—Douglas fir is obviously more expensive.

Do you also have empirical experience, or are you just copying your arguments from Wikipedia or similar sources?

Try using larch wood—it lasts 100 years or more if not covered with the cheapest wood paint.
That’s how the old builders around here used to build. They even built chimneys with it, and those did not burn down (using “moon wood”).

Only treated wood rots from the inside—see Swedish houses in Sweden. The red paint there just holds the wood fibers together, because the paints contain heavy metals that completely contaminate the wood fibers. No wood-boring beetle wants to touch that—it’s so toxic.

Bauexperte schrieb:

There is a petition committee—even in Brussels. Ask your questions there!

Not all, that’s true—but I still preferred the very old church or cathedral builders over the "old masters or master builders" you praise uncritically.

Dear Ms. Schenk, Brussels does not interest me, as I also build abroad … but in a simpler way, without energy saving regulations or forced restrictions, etc. These are German practices that do not concern me much.
The skill is rather to build small and pragmatically/energy efficiently (also financially), and I manage that without your lobby-influenced advice.

The old master builders constructed houses that still stand today. Concrete structures crumble because problem sources like missing eaves and flat roofs gradually destroy the building fabric through thoughtless planning.
(Just look at the Berlin Holocaust Memorial made of concrete—it started crumbling after only a few months, even with waterproof special concrete…)

Amazing how someone can still respond so angrily after 1.5 years.....

Apparently, user kamnik is unloading personal issues here at the main forum. After repeatedly mentioning x tons of charcoal briquettes and y cars on z sqm (square meters), I got myself a beer to endure this male chatter and the showing off (potency?).

Hello Yvonne,

now I "also" know what/who you mean

kamnik schrieb:

Dear Mrs. Schenk, I am not interested in Brussels since I also build abroad, ...but more straightforward, without energy saving regulations, forced restrictions, etc. These are German practices that don’t really concern me. The art is rather to be able to build a small and pragmatic/energy-efficient (also budget-friendly) house, and I manage that even without your lobby-influenced advice.

The "dear Mrs. Schenk" does not care at all where, why, or how you build. What I do care about is the manner of your conduct here; and I explicitly do not mean only your response to me. Therefore, I suggest you carefully reread your upcoming posts before clicking the send button, because I have no desire to tolerate rude behavior and the resulting nervous finger.

Since you obviously hold fixed opinions, the question naturally arises: what goals do you associate with the HBF?

Best regards, Bauexperte