ᐅ Comparison of Internal and External Insulation: Is External Insulation Significantly Better?

karl.jonas schrieb:

@SoL yes, that’s exactly what I’m currently considering (and I share your disappointment).

I understand, but after internal or external insulation, that wouldn’t be an issue anymore. Still, I shouldn’t place anything in front of the wall heating, right? I have plenty of ceiling height, but I can’t yet estimate the effort involved in retrofitting underfloor heating beneath the wooden plank floor. However, I’m probably willing to accept that—it’s for the next 100 years after all.

I don’t think it makes sense to retrofit old wooden planks for underfloor heating. If you are planning to use clay plaster indoors anyway, I would seriously consider wall heating. (I have had it personally for a year, my brother for about 15 years.) Although, without clay plaster in our case 😳

i_b_n_a_n schrieb:

I don't think it makes sense to retrofit old floorboards for underfloor heating. Since you are "already" planning to have clay plaster indoors, I would strongly consider wall heating systems. (Personally, I've had one for a year, and my brother for about 15 years). However, without clay plaster in our case 😳

...would you be willing to share some of your experience with the wall heating? How much surface area do you have compared to the living area / the built volume?

@i_b_n_a_n Okay, I will take a closer look at the option of "wall heating" (and I’m looking forward to your reply to the question from @SoL).
@Philfuel Thank you! So you didn’t do anything on the exterior? Yesterday, I watched the YouTube video "Internal Insulation II" by "Energiesparkommissar" (before the comments start: I know I need to gather more information besides YouTube videos, and I will definitely also consult an energy advisor...). The summary starting at about minute 10 is:

• In an old, porous brick wall, over the years, water and frost have penetrated; this cannot be fixed with "simple means";
• From minute 11, the possible measures are mentioned: applying a plaster or cladding;
• or hydrophobing (sealing the masonry).

Obviously, you didn’t do this, yet you have had good experiences. My wife also asked this morning why a cladding with bricks (@11ant refers here to facing bricks) is acceptable in terms of splash water and frost resistance, but keeping the old brickwork as the exterior wall is not. Well, maybe it’s because of the many holes / capillaries that have eaten into the old masonry over the years?

The walls are approximately 3 and 4 meters (10 and 13 feet) long and 2.55 meters (8.4 feet) high, with a total living area of about 65 square meters (700 square feet). The bathroom has tiles and underfloor heating and measures just over 9 square meters (97 square feet).

karl.jonas schrieb:

So you didn’t do anything on the outside?

Hi!
Yes, the old mortar joints were damaged because ivy had grown into them for decades. We had the facade sandblasted first. Then I removed all the joints with a chisel hammer and cleaned everything out, then reset and re-mortared all the loose bricks. That took a few days. Afterwards, we had the house re-pointed – which turned out to be much cheaper than expected. Finally, I impregnated the entire surface.
So yes, the facade was renovated. But we would have had to do that even without the interior insulation. For us, it was also important that the work could be done as DIY, including the interior insulation, which was always a deciding factor. If you have brickwork, removing the joints won’t be complicated. And maybe it’s necessary anyway?

karl.jonas schrieb:

You obviously didn’t do that, and yet you had good experiences. My wife also immediately asked this morning why cladding with bricks (@11ant means facing bricks here) is fine in terms of splash water and frost resistance, but keeping the old brickwork as an external wall is not. Well, maybe it’s due to all the holes/capillaries that have developed over the years in the old masonry?

Haha, who would make holes in it? The "stone louse" is a hoax. Frost causes damage by cracking, it doesn’t create capillaries. A brick veneer wall is usually installed (with an air gap) in front of the structural wall, so it is not part of it, and as a result there is no shared moisture balance. Overall, after much consideration involving the pros and cons regarding sandblasting, sealing, repointing, and interior insulation, I would lean toward those options. If I’m not mistaken, the energy saving advisor also works individually and provides constructive advice, so they are not just a complaint expert and certainly not a half-knowledge entertainment YouTuber. Therefore, I am confident that you can get a sensible, well-planned proposal from them. I found a service area radius of 50 km (30 miles) around Darmstadt online, but I think a trip from SU to DA (about two hours’ driving time) would be worth it. However, I have not met them in person yet.

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