Insulate glass blocks through a front panel

Hello,

I am currently in the process of buying a house that is a bit older, but I like it precisely because of that and want to preserve the appearance as much as possible while improving the terrible energy efficiency (269.3 kWh/(m2·a)) as much as possible.

One problem is certainly the uninsulated extension in which there are two glass block panels (approx. 250 cm * 300 cm and 80 cm * 230 cm). The blocks are narrower than the surrounding wall (24 cm, aerated concrete) and flush on the inside, so that on the outside there is a free strip about 6 cm wide all around.

My idea would now be to bolt small wooden slats all around on the outside of the wall as stops / spacers (2 cm slats), then insert one (or more) glass or acrylic glass panes, and then attach another 2 cm lathing as a frame.

This would only slightly affect the appearance, but do I achieve my goal of better insulation or will I cause problems in the long run.

Thanks

Hans-Joerg

What purpose do the glass blocks serve? Why not just replace them with "normal" windows (fixed glazing)?

My idea would be to drill small wooden slats all around on the outside as a stop/spacer in the wall (2 cm slats), then insert one (or several) glass or acrylic glass panes and afterwards attach another 2 cm lathing as a frame.

Probably brings exactly 0 in terms of energy.

What purpose do the glass blocks serve?

Let light through

Why not just replace them with "normal" windows (fixed glazing)?

We like the look - otherwise there is no other reason.

Probably brings exactly 0 in terms of energy.

The additional pane creates an insulating air cushion, basically just like the old double-glazed windows which still had "normal" air between the individual panes. It is clear that this is not as efficient as modern insulating glazing, but I cannot imagine that it has no effect at all.

I am a bit afraid that moisture could condense between the panes since the surrounding masonry is capillary.

Hans Joerg

Extension, old, high energy consumption,
the windows are not the only issue,
there is no insulation in the ceiling,
floor, walls, doors without insulation,
first get an idea of the actual condition of the house, then make a plan with an energy consultant including the costs of the individual measures and then a plan for the execution, you are groping in the dark
Regards Nida
PS: Double windows are never airtight, they ventilate dry

Extension, old,

the extension is what is relatively new (around 1968), the rest is old (around 1850)

high energy consumption, the windows are not the only cause,

Of course not [*], the glass blocks are—regarding energy consumption—just one of many problems.

first get an impression of the current condition of the house,

Apart from the energy consumption, this house has no problems. The condition of the building is really good, and on the second inspection I had a building expert with me. But he also said that (with my priorities) it would be difficult to achieve a good energy retrofit. I could carry out a number of individual measures * to improve the situation, but the big solution (energetically speaking) probably wouldn’t be done. He didn’t say much specifically about the glass blocks, which is why I addressed it here. This is less due to the building fabric and more to the external circumstances. The old building (1850) consists of basalt stone or basalt lava, not plastered on the outside, which I like very much and for this reason I do not want to insulate it from the outside. The extension made of aerated concrete (with the mentioned glass blocks) is built into a hillside, so basically the entire ground floor is embedded into the slope on two sides and on one side is attached to the garage. Here too, external insulation is difficult for obvious reasons, especially since another house is located further up the slope; digging away the slope to get to the outside is therefore not easily possible. The first floor of the extension protrudes into the slope on one side, the other two sides are surrounded by a prefabricated, enclosed winter garden. cu Ha-Joe * He suggests (no claim to completeness, written off the top of his head) * replacing the windows * replacing the old exterior roller shutters with motorized ones if possible; on this occasion closing the passages for the strap bands, etc. * having the roof redone sometime (which is planned anyway) and adding insulation from the outside in addition to the existing interior insulation * if I absolutely do not want to insulate the old house from the outside (which he recommends), I should have a diffusion-open interior insulation installed, but it should not be 3–4 cm thick; in his opinion I should carefully look for someone who really knows how to do this well—his skepticism is noticeable. In any case, I should first have determined the water vapor diffusion coefficient of the unplastered basalt walls and then contact him again before insulating. He seems particularly concerned about this part. * in the case of interior insulation, wall heating systems would not be bad or would improve the situation (I realized I did not ask which situation he meant, I will do so if I contact him again) * if I have interior insulation installed, one or the other ventilation unit would probably not be a bad idea either * he would have the fully open sides of the extension insulated from the outside, the other sides I should observe for one or two years first to see if the walls always remain completely dry.

We like the look - otherwise there is no other reason.

I can't imagine that people are into the look without some kind of cladding. But well, as a missionary, I don't really understand BDSM.

The laminated glass creates an insulating air cushion, basically just like the old multi-pane windows where there was still "normal" air between the individual panes. It's clear that this is not as efficient as modern insulated glazing, but I can't imagine that it has no effect at all.

The "normal" air has, firstly, been replaced by a special gas that doesn't form dew droplets; and secondly, this gas filling is tightly sealed, which the laths won't achieve.