Hello everyone!
I am going to build a house that is 11m wide and 8 meters deep.
The ground floor will consist of a slab and become quite a large garage, with raised wall height and a pitched roof.
The garage will have an internal ceiling height of about 2.40, the rest will be living space.
I want the garage section to be externally plastered, with the wall height and the rest in wood.
He wants to frame the garage with wood, put 12 mm outdoor gypsum boards, then styrofoam that is screwed into the frame, a reinforcement mesh, and then spray the facade, which is then ready to be insulated and clad on the inside.
What do you who know about this say? Very grateful for opinions!
I am going to build a house that is 11m wide and 8 meters deep.
The ground floor will consist of a slab and become quite a large garage, with raised wall height and a pitched roof.
The garage will have an internal ceiling height of about 2.40, the rest will be living space.
I want the garage section to be externally plastered, with the wall height and the rest in wood.
He wants to frame the garage with wood, put 12 mm outdoor gypsum boards, then styrofoam that is screwed into the frame, a reinforcement mesh, and then spray the facade, which is then ready to be insulated and clad on the inside.
What do you who know about this say? Very grateful for opinions!
No!!!
You should (must) have an air gap between the wooden frame and the plaster!
Preferably between the styrofoam and the outdoor gypsum, but then you lose the insulation ability of the styrofoam (cellplast) and can then rather use a board material. (Follow manufacturers' recommendations.)
For example, NCC has built a lot of houses in the way your contractor wants to do, and they have, among other things, had to replace the facade on ~200 newly built houses due to moisture problems. The most noted area is called Annehem:
http://www.nyteknik.se/nyheter/bygg/byggartiklar/article75932.ece
http://www.byggnyheter.se/2008/09/ncc-letar-fukt-pa-annehem
http://www.nyteknik.se/nyheter/bygg/byggartiklar/article75932.ece
You should (must) have an air gap between the wooden frame and the plaster!
Preferably between the styrofoam and the outdoor gypsum, but then you lose the insulation ability of the styrofoam (cellplast) and can then rather use a board material. (Follow manufacturers' recommendations.)
For example, NCC has built a lot of houses in the way your contractor wants to do, and they have, among other things, had to replace the facade on ~200 newly built houses due to moisture problems. The most noted area is called Annehem:
http://www.nyteknik.se/nyheter/bygg/byggartiklar/article75932.ece
http://www.byggnyheter.se/2008/09/ncc-letar-fukt-pa-annehem
http://www.nyteknik.se/nyheter/bygg/byggartiklar/article75932.ece
Arrange an air gap somewhere between the insulation and the plaster...
Example from inside to outside:
*Gypsum
*Plywood /chipboard (For mounting, e.g., paintings, shelves)
*Installation zone (wood studs & insulation, as well as space for electricity & pipes)
*Vapor barrier /-retarder (ÅB Building plastic or wind barrier)
*Wood frame & insulation
*Exterior gypsum or wind barrier
*Air gap
*Sheet material
*Plaster (& mesh)
Example from inside to outside:
*Gypsum
*Plywood /chipboard (For mounting, e.g., paintings, shelves)
*Installation zone (wood studs & insulation, as well as space for electricity & pipes)
*Vapor barrier /-retarder (ÅB Building plastic or wind barrier)
*Wood frame & insulation
*Exterior gypsum or wind barrier
*Air gap
*Sheet material
*Plaster (& mesh)
Both STO and Maxit use approved systems where work is done in this manner (without an air gap) but with stone wool boards instead of polystyrene, furthermore, the render itself is of a type that is completely diffusion-open to allow breathing.
Even if the render is diffusion-open, it still feels like a risk...
A diffusion-open render allows the wall to dry outwards, but if you have a leak where water comes in every time it rains, it's not certain that it will dry between rain showers.
Diffusion is a rather slow process and while the wall is drying out, you will have too high a moisture content in the wall.
It all depends on the amount of moisture that enters during rain in relation to the drying time. Personally, I wouldn't want to take the chance...
A diffusion-open render allows the wall to dry outwards, but if you have a leak where water comes in every time it rains, it's not certain that it will dry between rain showers.
Diffusion is a rather slow process and while the wall is drying out, you will have too high a moisture content in the wall.
It all depends on the amount of moisture that enters during rain in relation to the drying time. Personally, I wouldn't want to take the chance...
