Croatia - Structural engineer requires 23cm casting against existing interior wall

[mvs]

20mm gypsum board is significantly heavier and slightly stiffer than 13mm gypsum board. This means a lot for sound insulation. A common recommendation is, for example, double gypsum boards on the wall towards the sound source as a good (price and space) solution.
Unfortunately, I don't have a relevant test of it in my head right now.

Ok, good to know. Thanks.

 

[mvs]

The sound of footsteps is somewhat reduced with insulation in the floor structure, but if you want to eliminate more of it, a footstep sound-dampening underlay is better...
...
I wouldn't have installed a vapor barrier unless it's used consistently throughout the entire house...

We will have a 5mm underlay/parkett underlay between the OSB and the parquet floor to minimize footstep noise. Would we have any additional benefit from also placing a 5mm underlay on top of the glulam beam so that the OSB does not rest directly on the glulam beam?

Regarding the vapor barrier, I don't think they have planned anything for the walls. However, they have for the roof. I will ask the architect.

 

[Plupp 405730]

We will have a 5mm underlayment/parkettunderlag between the OSB and the parquet floor to minimize impact noise. Would we have any additional benefit from also laying a 5mm underlayment on top of the glulam beam so that the OSB doesn't rest directly on the glulam beam?

Regarding the vapor barrier, I don't think they've planned anything for the walls. However, for the roof. I will ask the architect.

No, it's more important to screw/nail glue the subfloor against your glulam beams..
5mm is sufficient, we don't normally have it in our single-family houses, it is used more in multi-family houses..
Yes, the roof is another matter where I would put a vapor brake in your situation, if these are not in that country, it is easy to buy some from here..

https://www.isover.se/supporten-tipsar/hur-fungerar-variabla-angbromsen-isover-varior-xtra

 

[mvs]

Just wanted to let you know that I have now started a separate thread for this project.

You can follow it here:
https://www.byggahus.se/forum/threads/sommarhus-i-kroatien-renoveringsprojekt.509243/#post-5583897

 

[mvs]

50mm is enough

Just about to send an email to the architect about this. Shouldn't such an isodrän panel be mounted on the outside of the wall? Here we share a wall with the neighbor, so it would have to be on the inside of our wall. Is that ok? And do you finish with a drywall panel in that case, or is something else needed between the isodrän panel and the drywall panel?

 

[Matti_75]

I would place insulation between the walls so any moisture can run down outside the basement.

 

[mvs]

I would insulate between the walls so any moisture can run down outside the basement

To clarify, it is a single thick wall (mostly made of stone). On one side of this thick wall, you are inside our house, and on the other side of the thick wall, you are inside the neighbor's house. So there is no possibility to lead moisture outside the basement. Imagine a wall that divides two rooms inside your own house ... same principle.

 

[mvs]

To clarify, it is one thick wall (mostly made of stone). On one side of this thick wall, you are inside our house, and on the other side of the thick wall, you are inside the neighbor's house. So there is no possibility to direct moisture outside the basement. Imagine a wall that divides two rooms inside your own house... same principle.

I'm thinking that the best approach might be to scrape away all the loose material on the inner wall and then install a 20mm gypsum board, but with a 30-50mm air gap so that the old wall can breathe. Does that sound reasonable? If you then happen to find a beautiful stone wall behind it, it might actually look nice to leave it fully exposed.

 

[Dublin]

I'm thinking that the best option might be to scrape away all the loose stuff from the inner wall and then install a 20mm plasterboard, but with a 30-50mm air gap in between so that the old wall can breathe. Does that sound reasonable? If a nice stone wall is found behind, it might indeed be attractive to leave it fully exposed.

Why not just go with plastered inner walls and tiles/stone floors? Paint the walls with silicate paint so that they can breathe. You may need a dehumidifier to keep the humidity in check. Do you know how the moisture is entering the basement? Is it through the wall, floor, or air? I guess it can get very warm and humid there in the summers, and when outside air enters a cold basement and cools down, you'll get a lot of moisture in.

 

[Matti_75]

I thought you were going to cast new walls according to your first post, hence the answer. Plastering is the best for your old walls. Gypsum in the basement can mold.

 

[mvs]

Why not just go with plastered interior walls and tiled/stone floors? Paint the walls with silicate paint so they can breathe. A dehumidifier might be needed to control the humidity.
Do you know how the moisture gets into the basement? Is it through the walls, floor, or air? I guess it can get very warm and humid there in the summer, and when the outdoor air comes into a cold basement and cools down, you can get a lot of moisture.

👍 Exactly what I suggested in my email to the architect, i.e. plaster the interior walls and then paint. You often see that down there. It also feels good to be able to keep track if any place starts to look damp.

Regarding moisture, almost all basements in the old town are damp. It's often a combination of the houses being built right next to each other (without any thought of drainage, moisture barriers, etc. - things they didn't care about back then) and the very warm air hitting cold stone walls in the basement and condensation forming. It often gets better if you can get the air to circulate. As soon as it starts to blow, the humidity drops significantly. Our basement is probably one of the least humid I've seen, so in that way, we're lucky. However, the walls furthest in have damp spots, so we will install a ventilation system to get the air to circulate better.

 

[mvs]

I thought you were going to cast new walls according to your first post, hence the answer. Plastering is the best for your old walls.

👍 Sounds reasonable!

 

[mvs]

Plasterboard in the basement can mold.

Ok, good to know. I always thought that plasterboard was very resistant to dampness and mold.

 

[Dublin]

Ok, good to know. I've always thought that drywall is very resistant to moisture and mold.

If you decide to use any board material, wet room boards are preferable, but as mentioned, better to have plastered walls.

 

[Dublin]

The walls at the back have damp spots, so we will install a ventilation system to improve air circulation.

Here I think it's good to read up thoroughly. It's tricky with cold basements and warm, humid outside air. Moderate ventilation combined with appropriate dehumidification is probably the way to go, but it doesn't seem always easy to achieve a good solution.