Additional insulation over a row of Leca, should vapor barrier/sill insulation be used?
Hi,
We have recently erected a garage, the frame is in classic 145-timber and the foundation is an insulated slab on the ground.
Due to the proximity of a slope that belongs to the neighbor, one side is built with a layer of concrete blocks (height 19cm) to meet the higher ground level. A Platon mat is attached on the outside of the blocks.
The plan was to insulate the frame as usual and apply the plastic sheeting, then add additional insulation with 45x45 before OSB/drywall. In doing so, I would like to extend the OSB/drywall to cover the row of concrete blocks at the bottom.
The question now is, should I extend the plastic sheeting over the concrete blocks? Should I use sill gasket or similar between the 45x45 and the concrete blocks (as well as the floor)? Or should I skip the insulation? Or should I not extend the wall over the concrete blocks at all?
Grateful for any tips!
We have recently erected a garage, the frame is in classic 145-timber and the foundation is an insulated slab on the ground.
Due to the proximity of a slope that belongs to the neighbor, one side is built with a layer of concrete blocks (height 19cm) to meet the higher ground level. A Platon mat is attached on the outside of the blocks.
The plan was to insulate the frame as usual and apply the plastic sheeting, then add additional insulation with 45x45 before OSB/drywall. In doing so, I would like to extend the OSB/drywall to cover the row of concrete blocks at the bottom.
The question now is, should I extend the plastic sheeting over the concrete blocks? Should I use sill gasket or similar between the 45x45 and the concrete blocks (as well as the floor)? Or should I skip the insulation? Or should I not extend the wall over the concrete blocks at all?
Grateful for any tips!
Know-It-All
· Västra Götaland
· 11 967 posts
Pull the plastic all the way down and out onto the floor. Then start with the first 45x45 against the floor.
Know-It-All
· Västra Götaland
· 11 967 posts
Hmm right. 45mm mineral wool insulates roughly like 19cm leca. Then you can replace the mineral wool with foam plastic and skip the plastic down there or run the plastic on the inside and sacrifice the installation layer there.
Moisture wants to condense on the cold side. In a garage, which side is the colder side in the summer?
Insulate the foundation on the outside and consider the vapor pressure. Is the moisture coming from the inside or outside?
In unheated spaces, it's not obvious to use plastic in the walls.
Personally, I would build a layer with leka (more where needed) and plaster the foundation.
Just to be able to hose down when needed, and to avoid damage when driving in a snow-covered car.
Insulate the foundation on the outside and consider the vapor pressure. Is the moisture coming from the inside or outside?
In unheated spaces, it's not obvious to use plastic in the walls.
Personally, I would build a layer with leka (more where needed) and plaster the foundation.
Just to be able to hose down when needed, and to avoid damage when driving in a snow-covered car.
You should have insulated the outside of the leca wall, with something like iso-drän or similar. Then it wouldn't be a tricky question now.
It is quite possible that the moisture load will always come from the outside, as the garage may be relatively cool and have little/no moisture production, while the ground outside the foundation wall can be considered to always have 100% RH.
In that case, the vapor barrier should be on the "wrong side," i.e., as close to the ground as possible.
But it will remain a bit unclear which way the moisture will want to travel in your construction, making it always difficult to say for sure how you should proceed.
Perhaps skip the moisture barrier entirely and build with diffusion-open inorganic materials...
It is quite possible that the moisture load will always come from the outside, as the garage may be relatively cool and have little/no moisture production, while the ground outside the foundation wall can be considered to always have 100% RH.
In that case, the vapor barrier should be on the "wrong side," i.e., as close to the ground as possible.
But it will remain a bit unclear which way the moisture will want to travel in your construction, making it always difficult to say for sure how you should proceed.
Perhaps skip the moisture barrier entirely and build with diffusion-open inorganic materials...
Know-It-All
· Västra Götaland
· 11 967 posts
If you're unsure, it's certainly not a bad idea to use diffusion-open methods.
Maybe you could apply a layer of lättbetong and then plaster over it instead?
Maybe you could apply a layer of lättbetong and then plaster over it instead?
My thought, place a steel sill along the floor, insulate against the leca and extend the vapor barrier outside the insulation for that part. It could be risky considering moisture from outside. An alternative is to insulate and plaster the lowest section.
Thank you for all the answers.
The idea is that the garage will be heated with a heat pump, I'm considering letting the vapor barrier end at the top edge of the lecablock and only insulating with sill insulation against the studs.
Alternatively, I could avoid extending the paneling past the leca, but it will look a bit odd since I only have leca at the bottom on two of the walls.
The idea is that the garage will be heated with a heat pump, I'm considering letting the vapor barrier end at the top edge of the lecablock and only insulating with sill insulation against the studs.
Alternatively, I could avoid extending the paneling past the leca, but it will look a bit odd since I only have leca at the bottom on two of the walls.