Wall construction in 40s house

[Snck]

Hello, I'm trying to perform an energy calculation on my parents' 1940s house. Does anyone know a bit better how the exterior walls are constructed?

What I know is that from the inside, there's tretex of about 25mm, then a plank wall of about 2-3cm, then an air gap. Does anyone know more precisely what it looked like back in the day? Possibly any old drawings?

Best regards

 

[useless]

It can probably vary a lot from house to house and depending on if something was done after the construction. If you want to make a reasonably accurate calculation, you probably have to try to check exactly how it is done.

 

[Snck]

It can probably vary a lot from house to house and if something has been done after the construction. If you want to make a somewhat accurate calculation, you probably have to try to see exactly how it is done.

Yes, that would be the best, but it's unfortunate to have to tear down a wall just to take a look..

The walls I've had open before are tretex 25mm, probably 34mm raw planks, about 3cm air gap and some kind of plank wall with asphalt paper of some kind with reed mat and plaster on that.
The walls are about 15cm thick in total.

I was thinking if someone has had something similar, you could use the dimensioning they've come up with :kr

 

[justusandersson]

In its original state, the wall construction was often as follows, from inside to out: 15 mm plaster on reed mat (called rörning), 25 mm split panel (common boards mounted diagonally and split with an axe after installation), 50-75 mm (2-3 inch) plank, tarred paper, 25 mm outer panel + battens. In your case, the treetex and possibly something else seems to have been added afterwards. Plank thickness and house height are related. In a 2 to 2½ story house, you can assume that it is 3-inch plank. The insulation value of the wall before any extension is roughly equivalent to 40-45 mm mineral wool. However, that is not the whole truth. Due to its weight and density, it has better energy properties than a corresponding stud wall.

 

[Snck]

In its original state, the wall construction was often as follows, from inside to out: 15 mm plaster on reed mat (called "rörning"), 25 mm splinter panel (ordinary boards mounted diagonally and splintered with an axe after installation), 50-75 mm (2-3 inches) planks, building paper, 25 mm outer panel + battens. In your case, it seems that the Treetex and possibly something else have been added afterwards. The plank thickness and house height are related. In a 2 to 2-1/2 story house, you can assume it is 3-inch planks. The insulation value of the wall before any additions is roughly equivalent to 40-45 mm mineral wool. However, that's not the whole truth. Due to its weight and density, it has better energy properties than a comparable stud wall.

Okay, sounds reasonable, but on the house, the outer layer is plaster with reed mat, then 2-3 inch planks with air gap, then 1-1.5 planks with nailed Treetex, and currently gypsum, would that be a reasonable construction?

 

[useless]

Yes, that would be the best but it's boring to tear up a wall just to check..

You don't have to tear up an entire wall... Check at the bottom of the facade if you can see anything, remove a window trim, or drill a hole in a hidden spot. Maybe there's a storage or attic where there's nothing inside the frame?

 

[Snck]

You don't need to cut open a whole wall... Check the lower edge of the facade if it's possible to see anything, loosen a window frame or drill a hole in a hidden spot. Maybe there's a storage or cold attic where there's nothing on the inside of the frame?

unfortunately, I've looked a bit, plastered facade with a brick basement so nothing is visible from the outside, haven't found any other place to check either..

 

[justusandersson]

Rendered façade (plaster on lath outside paper-covered plank wall) was also quite common. With your description (which I initially misunderstood), I believe that the treetex and what's inside it are original. The drywall has definitely been added later. Gypsum didn't come until the introduction of stud houses in the early 1950s. There's no need to demolish the wall. Drywall is a replacement for plaster as an interior surface.

 

[Snck]

Plastered facade (plaster on lathing outside paper-clad plank wall) was also quite common. With your description (which I first misunderstood) I believe that the treetex and what is inside it are original. The gypsum board was definitely added later. Gypsum didn't come until the frame houses in the early 1950s. There is no need to tear down the wall. Gypsum is a substitute for plaster as an interior surface.

Okay, you seem knowledgeable on the subject, so 20mm plaster, 2-3 inch plank as the frame, air gap of 20-30mm, 1-1.5 inch plank, treetex at 25mm, and finally 12mm gypsum board,

would that be a reasonable construction for the vintage? And reasonably correct to input into the software to calculate an energy assessment of the house.

Thanks for the answers!

 

[justusandersson]

Absolutely.