We have a house built in the 50s, and we're going to renovate the upper floor. We thought, why not open up to the ridge and make it a bit more airy? The insulation today consists of wood shavings or something similar. How do you solve it with an air gap, insulation, etc.? I understand that the trusses were not made to be visible when they were built, but I don't see that as the biggest problem. Grateful for information and words of wisdom.
/Ecke
/Ecke
I assume you have a typical 1 1/2-story house with about 115 sqm of living space. Such a house has a frame truss. The parts that can look unattractive are the so-called collar beams. They can be replaced with more aesthetically pleasing and slimmer variants.
When it comes to insulating along the outer roof, there are two options depending on how the roofing is done. If the outer roof is covered with underlay felt, you need to create an air gap of a couple of centimeters along the inside of the roof boards. The air gap should have ventilation openings at the eaves and preferably also at the ridge. The simplest way to arrange the latter is to place vents at the top of the gable peaks and not extend the insulation all the way up, so that a small ventilation channel is formed. The other option is that the outer roof's waterproofing layer consists of a diffusion-open membrane (less common, but gaining popularity). In that case, you can skip the air gap and have a more compact roof.
Regardless of the method, the inside of the insulation should be covered with a diffusion-tight plastic film. How much insulation you should fit is a matter of compromise. Reaching today's new building standards is not reasonable, nor is it justified considering that the other parts of the house are at a much lower level. It is possible to calculate what is optimal.
When it comes to insulating along the outer roof, there are two options depending on how the roofing is done. If the outer roof is covered with underlay felt, you need to create an air gap of a couple of centimeters along the inside of the roof boards. The air gap should have ventilation openings at the eaves and preferably also at the ridge. The simplest way to arrange the latter is to place vents at the top of the gable peaks and not extend the insulation all the way up, so that a small ventilation channel is formed. The other option is that the outer roof's waterproofing layer consists of a diffusion-open membrane (less common, but gaining popularity). In that case, you can skip the air gap and have a more compact roof.
Regardless of the method, the inside of the insulation should be covered with a diffusion-tight plastic film. How much insulation you should fit is a matter of compromise. Reaching today's new building standards is not reasonable, nor is it justified considering that the other parts of the house are at a much lower level. It is possible to calculate what is optimal.
Yes, a 1.5-story house, there's roofing felt under the tiles, so a ventilation gap is necessary. How much insulation should one have? Would it look like this if we go through the construction:
Roof boards on the outer roof
Ventilation gap
Insulation
Wind barrier?
Furring strips
Drywall/indoor panel
/Ecke
Roof boards on the outer roof
Ventilation gap
Insulation
Wind barrier?
Furring strips
Drywall/indoor panel
/Ecke
It should be a diffusion-tight layer (e.g., plastic film) not wind fabric. Regarding the thickness of the insulation, I believe around 200 mm may be suitable. The house's exterior walls only have 100 mm mineral wool. Increasing to 300 mm only provides a marginal improvement in the house's overall U-value, which is not proportionate to the significant additional work.
The house is built with concrete hollow blocks and light concrete/blue concrete in the walls. There is no ventilation in the eaves as it appears today. There is only one on each side high up on the gable peak in the space above the ceiling. How would one solve ventilation in the eaves, drill through the wall and into the future air gap? Or perhaps a mold stopper at the top and bottom in each section?
Perhaps the kattvindar can be used as ventilation ducts via gable vents? Please post drawings.
Yes, there is attic space (kattvind) on each side. Do you mean that one should have an opening at the bottom in each compartment through the insulation to the attic space and at the top ridge, a mold stopper or whatever they are called? I honestly don't know if I have any drawings of the current roof construction. The attic spaces today have no ventilation at all, only in the space between the inner ceiling and the ridge.
Yes, and a corresponding one at the top for a small air channel.E Ecke16 said:
Was up looking at the roof trusses today, they have older dimensions around 140x75. Do you really need as much as 200mm insulation? To get it with an air gap, you have to build up almost a decimeter, feels like it steals a lot then...
It should be 75x150 since real inch measurements were used for cross-sections at that time.
No one is forcing you to have thicker insulation than what fits. If you have 150 mm of sawdust or cutter chips today, it corresponds to about 75 mm of mineral wool. So, most of what you can add will be an improvement. The air gap should be about 25 mm high.
No one is forcing you to have thicker insulation than what fits. If you have 150 mm of sawdust or cutter chips today, it corresponds to about 75 mm of mineral wool. So, most of what you can add will be an improvement. The air gap should be about 25 mm high.
Yes, battens will be great. You don't need to use oil-hardened board but it works, of course.
Reviving old thread. Finally getting to it and demolishing the upper floor. Planning to insulate between the rafters with iCell boards 120mm plus air gap, which is what I have room for without having to lower the ceiling. How does such a board perform compared to, for example, 120mm fiberglass? Another question, I will now insulate all the way down to the walls, how should I handle ventilation in the cavities? They will be in contact with the existing ridge vent at each end of the house, but do I need to allow air at the bottom of each cavity as well?
/Ecke16
/Ecke16