Leca basement wall with external insulation, should one have a foam frame around basement windows
If you are building a basement wall with Leca and have external insulation, how large should the holes for basement windows be? Should you make the holes with a few cm of margin to the frame just right for caulking, or should you have a margin for, for example, 5cm XPS around the window so that you don't get a thermal bridge around the window? The reason for XPS is that I judge EPS to be on the softer side.
Are you going to have plaster on the outside of the insulation? What thickness do you have for insulation and Leca?
The insulation should be covered with something. Either plaster or, even better, facade stone
http://www.molnsatra.se/umbraco/ImageGen.ashx?image=/media/302628/murbeklädnad grafit-1.jpg
I am open to suggestions regarding the insulation. One or two layers of 5 cm cellplast is what I'm leaning towards.
However, I have only found metal fastening systems.
http://www.liuskemestarit.fi/images...ct/luonnonkivi-musta-laatta-himalaja-0103.jpg
I would prefer a fastening system that insulates somewhat better.
An idea I've had is to attach battens outside the first layer of cellplast which I then attach the facade stone to. Then the distance between the inner and outer fastening points of the battens becomes "insulation."
I have considered composite decking as batten material.
I have also thought about making the fastening with flat-headed screws, i.e., not countersunk, so they rest on the screws and are kept in place by the screw heads. They need to be screw heads that aren't too small. With that system, it would be possible to replace a stone piece if needed.
http://www.molnsatra.se/umbraco/ImageGen.ashx?image=/media/302628/murbeklädnad grafit-1.jpg
I am open to suggestions regarding the insulation. One or two layers of 5 cm cellplast is what I'm leaning towards.
However, I have only found metal fastening systems.
http://www.liuskemestarit.fi/images...ct/luonnonkivi-musta-laatta-himalaja-0103.jpg
I would prefer a fastening system that insulates somewhat better.
An idea I've had is to attach battens outside the first layer of cellplast which I then attach the facade stone to. Then the distance between the inner and outer fastening points of the battens becomes "insulation."
I have considered composite decking as batten material.
I have also thought about making the fastening with flat-headed screws, i.e., not countersunk, so they rest on the screws and are kept in place by the screw heads. They need to be screw heads that aren't too small. With that system, it would be possible to replace a stone piece if needed.
The recess for the window frame should be the same size in both the leca wall and what is outside. A suitable size is the frame's outer dimensions plus about 15 mm on each side. In depth, the frame should be placed so that it can be sealed, if necessary with sealant. In a wall with exterior brick (facade brick), the frame is usually placed at a 1/4-brick depth, approximately 6 cm. If you choose some form of plaster over the insulation, the plaster should also be on the sides of the window opening. In a wooden facade, the window frame is usually aligned with the exterior panel so that molding can be nailed onto both the frame and the panel.
I believe that one should avoid organic material on the outside of lecastone. It is common to use various forms of metal clamps to attach the insulation. When cladding an entire facade with natural stone as in your examples, each individual stone is held up with metal brackets. Generally, there is no insulation directly behind such stone facades.
I believe that one should avoid organic material on the outside of lecastone. It is common to use various forms of metal clamps to attach the insulation. When cladding an entire facade with natural stone as in your examples, each individual stone is held up with metal brackets. Generally, there is no insulation directly behind such stone facades.
"The recess for the window frame should be equally large both in the cinder block wall and in what will be outside. A suitable size is the frame's outer dimensions plus about 15 mm on each side. In depth, the frame should be positioned so it can be sealed, if needed with sealant. In a wall with cladding brick (façade brick), the frame usually sits at 1/4-brick depth, i.e., about 6 cm. If you choose some form of plastering outside the insulation, the plaster should also be applied to the sides of the window opening. In a wooden façade, the window frame is usually set flush with the outer panel so that the trim can be nailed onto both the frame and the panel."
I accept all of this, the question is whether there should be a layer of polystyrene, about 5 or 10 cm thick, beside the window and beyond the 15 mm before reaching the cinder block or if it should be cinder block bordering the 15 mm.
"I think one should avoid organic material on the outside of the cinder block."
I completely agree, and apparently, I had a mental lapse when writing because I do not want to use materials that can rot. A material that isn't affected by moisture and is reasonably insulating and can be screwed into is what I would like.
Like, composite decking, if it doesn't rot as well. I assume that moisture must be able to get in somewhere and find its way along the fibers to cause rotting, albeit slowly.
"It is common to use different types of metal brackets to attach insulation. When covering an entire façade with natural stone as in your examples, each individual stone is held up with the help of metal fasteners. Usually, there's no insulation directly behind such stone façades."
If you want insulation between the cinder block and stone, is it possible to arrange that? If so, how?
Or you transition to isolating cinder block just below the surface that will be clad with stone.
At the bottom, it will be plaster cinder block plaster polystyrene
at the top, it will be plaster isolating cinder block plaster façade stone
I accept all of this, the question is whether there should be a layer of polystyrene, about 5 or 10 cm thick, beside the window and beyond the 15 mm before reaching the cinder block or if it should be cinder block bordering the 15 mm.
"I think one should avoid organic material on the outside of the cinder block."
I completely agree, and apparently, I had a mental lapse when writing because I do not want to use materials that can rot. A material that isn't affected by moisture and is reasonably insulating and can be screwed into is what I would like.
Like, composite decking, if it doesn't rot as well. I assume that moisture must be able to get in somewhere and find its way along the fibers to cause rotting, albeit slowly.
"It is common to use different types of metal brackets to attach insulation. When covering an entire façade with natural stone as in your examples, each individual stone is held up with the help of metal fasteners. Usually, there's no insulation directly behind such stone façades."
If you want insulation between the cinder block and stone, is it possible to arrange that? If so, how?
Or you transition to isolating cinder block just below the surface that will be clad with stone.
At the bottom, it will be plaster cinder block plaster polystyrene
at the top, it will be plaster isolating cinder block plaster façade stone
Yes.U utbygget said:
I have insufficient knowledge about composite materials. In each individual case, one must probably read the manufacturer's advice.
When using natural stone as wall cladding, you would probably want an air gap behind it. In such (and many other cases), isoleca is an excellent alternative. An exterior wall of isoleca that is plastered on both the inside and outside is a wonderfully simple construction with excellent properties. If a leca wall is to be airtight, it must be plastered on both sides.
Why is it better to use leca instead of foam around basement windows?
Why should there be an air gap up to half the height of the house? I imagine that in the lower half there is negative pressure and in the upper half there is positive pressure in the house. In the basement, air will be drawn in during the winter, and the further in the air goes, the warmer it becomes, thus drying the air. Is an air gap needed up to half the height of the house then? If there is a risk of air escaping, i.e., on the upper floor, an air gap is obviously necessary.
I imagine composite joists like these so that they do not risk rotting and to ensure they provide some insulation and are strong enough to attach the facade stone to. I imagine the screw should reach through the first chamber so the screw has support in two layers of the plastic and then supports the weight of the stone when the screw extends about 3 cm and has the screw head outside the edge of the stone.
http://janssonpartner.se/parkmobler/plankorreglarsyllar/fyrkants-reglarsyllar-i-returplast
outside the plastered leca (to make it airtight). Then PU foam between the joists to provide a thin, well-insulated layer between the stone and leca.
Why should there be an air gap up to half the height of the house? I imagine that in the lower half there is negative pressure and in the upper half there is positive pressure in the house. In the basement, air will be drawn in during the winter, and the further in the air goes, the warmer it becomes, thus drying the air. Is an air gap needed up to half the height of the house then? If there is a risk of air escaping, i.e., on the upper floor, an air gap is obviously necessary.
I imagine composite joists like these so that they do not risk rotting and to ensure they provide some insulation and are strong enough to attach the facade stone to. I imagine the screw should reach through the first chamber so the screw has support in two layers of the plastic and then supports the weight of the stone when the screw extends about 3 cm and has the screw head outside the edge of the stone.
http://janssonpartner.se/parkmobler/plankorreglarsyllar/fyrkants-reglarsyllar-i-returplast
outside the plastered leca (to make it airtight). Then PU foam between the joists to provide a thin, well-insulated layer between the stone and leca.
A window frame must be able to be attached to a rigid material.U utbygget said:
I don't quite understand your reasoning here. An air gap behind, for example, facade bricks is not connected to any indoor space. However, you are correct that there are pressure differences in all air-filled spaces where there are temperature differences in height.U utbygget said:
It is quite possible that what you are thinking about composite beams can work. I haven't seen examples of such implementations. The question is whether the plastic has sufficient durability. As for natural stone-clad facades, I have some design experience, although it was a long time ago when insulation was not a major issue.