Building without a ventilation system using hollow bricks?

Hello Shism,

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

Regards Fabian

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 perforated bricks with perlite filling, 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.
:

cost correspondingly significantly more;
just compare the prices (marketing gag + money-making scheme)

This Rockwool stuff fell apart in my test setup in the basement. I wouldn’t use such a material. Rather
wood fiber mats + mesh + special plaster on the 50 cm thickness?

With today’s standard wall thickness of 36.5 cm and a U-value of 0.07 or 0.08 you will probably not quite make it. They will likely recommend at least a wall thickness of 42.5 or 49 cm. With bricks, the material price is almost proportional to the wall thickness, so you are looking at several thousand euros extra. :

That is wrong, since the one filled with mineral wool is noticeably more expensive than a comparable 49 cm plan brick without filling, with compressive strength class 8.

The one filled with mineral wool has a higher compressive strength and presumably you have to heat just as much with the 0.08 U-value as with a 50 cm plan brick, which has a laboratory U-value of 0.15. Whether you end up burning 2 tons or 3 tons of pellets is ultimately irrelevant and doesn’t make much difference if I build 30% cheaper and invest the rest in beech wood.

Also, the planner has to correspondingly enlarge the foundation slab and the roof (roof structure, roof tiles, etc.) for the same living area, which he will usually charge you accordingly based on the enlargement of the exterior dimensions. A thicker wall (36.5 vs. 49 cm) leads to an increase of the foundation slab by 5 square meters in a 10x10 meter house. Assume that the cost for the 5 square meters roughly corresponds to 5 square meters of additional living area per floor = 10 square meters. How much do 10 square meters more cost with your house planner/general contractor?:

10 m2 costs about 570 euros more for the foundation slab, about 270 euros more for reinforcement, and about 50 euros more for 0.4 m3 of concrete.
The additional cost for the roof is just 600 euros.
Or you manage inside with 20 cm less area – if someone spends the whole year just inside the house, then something’s wrong anyway.
Those who spend much time outdoors are usually tired in the evening and fall asleep quickly. In retirement the house is sold anyway, because an apartment is often more practical.
Therefore: a house is only a temporary overnight place – nothing else. The terrace area compensates a lot, like a winter garden extension.

My fear: KfW 40 is a big financial challenge for a stone-on-stone house. The credit you get from the KfW bank for the KfW 40 standard will never make up for your extra investment, even when you take into account saved energy costs and energy price increases. So why KfW 40?:

If you build without KfW, you build cheaper anyway. The only catch is the Energy Saving Ordinance 2016 which imposes requirements that hardly bring any effective benefit (overall balance). Because what use is a savings of 1 euro per square meter per year if I have to invest 200 times that amount so that in the end I receive a small saving, including a mold guarantee?

Somehow one should stay grounded.
If you build abroad, you don’t have the whole Energy Saving Ordinance stuff on your back. It’s only a German problem. Go to France… they don’t care. Sure, they also insulate, but in moderation.

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

The blower door test is also a matter, when people cut out the rubber seals at the top edge of the windows just to achieve a cozier room climate – or these forced ventilation slots in the roller shutter boxes or windows.

You can also over-isolate yourself to death?

Go to Holland/Amsterdam and ask the local planners what they think of ventilation systems.
There the trend is clearly away from ventilation systems because they make people sick.
They used to install the German technologies there…
Today only one-third of house builders install ventilation systems – that is the current state in the Netherlands.

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

In addition, all the pre-installations get heavily contaminated over time and the children breathe in the crap – no wonder more and more asthmatics are wheezing around….

If you put forward your personal opinion for discussion, you should not try to sell it as a fact. What you are presenting here is at best half-baked – and therefore dangerous nonsense for inexperienced construction laymen.

This is a planning tailored to a specific life situation; you copied the views from the front page of my homepage in the single-family house section. These views are an example of a cube.

With all due respect, Mrs. Schenk,
from a building physics perspective, flat roofs with their gutters are, to me, shoddy workmanship/botch, already from the planning phase
and sources of disturbance.
If water gets under the bitumen membranes, you will only notice the damage much later, when the frost breaks up the concrete slabs.
If you had personal experience with these construction damages, you would not resort to such a dilettante planning again; my father
knew all about it, due to poor advice.

Many of your "old" masters have produced this dangerous crap. By the way, just like their "estimates" of the heating energy demand of a single-family home. I know enough of them and "owe" them a not insignificant amount of additional and unnecessary work. Recently, one of your old "masters" again decided on short notice to install a 3 kW higher heat generator – better safe than sorry. Apart from the fact that it is completely unnecessary – the heating load calculation confirms the sold heat generator, this would have cost my clients an additional EUR 5-6 thousand. So much for the subject of "old masters" .

You don’t have a heating calculation done by a shady heating craftsman,
but by a proper heating planner, because you can hold them liable if they design a boiler that is too large or too small for you.
The master goes bankrupt and then there is nothing left to get, including expert costs.

Here is a commentary on the flat roof guideline for interested construction laymen:

"Since October 2008, the new flat roof guideline has been introduced as mandatory and has undergone many essential changes compared to the old version from September 2003, for example, regarding its scope, the rules for sealing, the materials used, etc. It has based its essential rules on DIN 18531 for unoccupied roofs.

I stick to the opinion that every flat roof structure is and remains botch. Why did the local municipality build a hip roof on the school (flat roof) after 30 years?
Because sand was falling from the ceiling… no, because all the ceilings were damp – because where on earth should all the water go if it actually rains properly?
Building physics: how do you want to drain thousands of liters of water through a 100 mm pipe?

If the respective client uses "Douglas fir" instead of spruce and maintains his facade, this statement misses the mark. But – and here we are again with you – Douglas fir is of course more expensive

Do you also have empirical values available or do you just copy your argumentation from Wikipedia-Hütte.de?

Take larch wood – it lasts 100 years and longer if you don’t plaster it over with the cheapest wood paint.
That’s how the old folks built here with us. They even built chimneys with it long ago and those did not burn down (moon wood).

Only treated wood rots from the inside – see Swedish houses in Sweden. The red paint there only holds the wood together because heavy metals are integrated in the paints, and the wood fibers are completely contaminated.
No wood-boring beetle even approaches it – that toxic.

There is a petition committee – also in Brussels. Ask your questions there!

Not all, that’s true – I still preferred the very old church or cathedral builders to the "old masters or master builders" you generally praise

Dear Mrs. Schenk. Brussels does not interest me, since I also build abroad, … but more simply minded, without energy saving regulations, forced patronizing, etc. These are German habits that don’t interest me much.
The art rather consists in being able to build small and pragmatically/energy-saving (also wallet-friendly) – and I manage that even without your lobby-soaked advice.

The old master builders built houses that still stand today. Concrete structures crumble because sources of disturbance like missing overhangs, flat roofs erode the substance step by step through brainless planning.
(Just look at the Berlin Holocaust Memorial made of concrete – it started crumbling after just a few months, even with waterproof special concrete…)

Amazing how one can still respond so upset after 1.5 years.....

Apparently, personal problems are being unloaded here at the HBF by the user kamnik. After the repeated mention of x tons of charcoal briquettes and y cars on z sqm, I got myself a beer to do justice to this male babble and to endure the bragging (potency?).

Hello Yvonne,

now "I too" know what/who you mean

dear Mrs. Schenk. Brussels does not interest me, as I also build abroad, ...but simpler minded,
without energy saving regulations, forced paternalism, etc. These are German ways that do not interest me much.
The art is rather to be able to build small and pragmatically/energy-saving (also for the wallet) and I manage that, even without your lobby-soaked advice.

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

Since you are obviously stuck in - set in stone - views, the question naturally arises for me, what goals do you associate with the HBF?

Rhenish regards