ᐅ Insulating the upper floor ceiling. The ceiling construction consists of panels mounted on battens.
Created on: 3 Jul 2009 11:33
M
MaikS
Hi
I wanted to insulate the ceiling of the upper floor since the attic is not developed.
The ceiling structure consists of panels (on battens) – straw clay plaster – cavity – floorboards.
At first, I thought of filling the cavity between the floorboards and clay plaster, but according to a company, the clay plaster’s fastening is not stable enough.
Now I am considering adding insulation on top of the floorboards. How thick should the insulation be at minimum, and what is the best construction method? What about a vapor barrier?
Best regards
Maik
I wanted to insulate the ceiling of the upper floor since the attic is not developed.
The ceiling structure consists of panels (on battens) – straw clay plaster – cavity – floorboards.
At first, I thought of filling the cavity between the floorboards and clay plaster, but according to a company, the clay plaster’s fastening is not stable enough.
Now I am considering adding insulation on top of the floorboards. How thick should the insulation be at minimum, and what is the best construction method? What about a vapor barrier?
Best regards
Maik
Hello @Maiks,
With such complex and problematic insulation work in the attic, you should neither rely on a local insulation "supplier" and the maybe resulting "good feeling" nor on hot tips from internet forums...
Here, only professional expertise on site counts! Measuring is better than looking and guessing...
At this point, only general principles can be outlined.
It still applies, for example, that the insulation performance of building layers should increase outward, while vapor resistance should decrease...
For what reason should a functioning building layer like the straw-clay rammed mix be replaced by another at relatively high effort?
Certainly only for a valid reason, for example, when the structural conditions do not allow any other option to improve the U-value with additional insulation layers... (U-values can not only be calculated, whether according to Glaser or with dynamic calculation methods, but also measured!)
Wood fiber insulation materials have somewhat lower insulation performance compared to mineral wool, but they do offer advantages in summer thermal protection...
For moisture regulation, the current filling material is almost certainly excellently suited. (Material moisture should be measured!)
By adding insulation, the current dew point moves outward.
Provided that the airtightness layer functions (testing for airtightness is strongly recommended), water vapor transport will by no means be negatively affected.
Materials are certainly not smarter than their installers!!!
(After more than 20 years of installation work and over 10 years of airtightness testing, I have seen enough sealing and insulation disasters...!)
While you can believe (well-intended) half-truths from friends, acquaintances, neighbors, and forum users, I would rather hire professionals with the necessary knowledge and experience to find an optimal solution based on the actual local conditions... even if it costs a few euros. At least they are also liable for their statements or executed services.
Best regards from Erfurt
With such complex and problematic insulation work in the attic, you should neither rely on a local insulation "supplier" and the maybe resulting "good feeling" nor on hot tips from internet forums...
Here, only professional expertise on site counts! Measuring is better than looking and guessing...
At this point, only general principles can be outlined.
It still applies, for example, that the insulation performance of building layers should increase outward, while vapor resistance should decrease...
For what reason should a functioning building layer like the straw-clay rammed mix be replaced by another at relatively high effort?
Certainly only for a valid reason, for example, when the structural conditions do not allow any other option to improve the U-value with additional insulation layers... (U-values can not only be calculated, whether according to Glaser or with dynamic calculation methods, but also measured!)
Wood fiber insulation materials have somewhat lower insulation performance compared to mineral wool, but they do offer advantages in summer thermal protection...
For moisture regulation, the current filling material is almost certainly excellently suited. (Material moisture should be measured!)
By adding insulation, the current dew point moves outward.
Provided that the airtightness layer functions (testing for airtightness is strongly recommended), water vapor transport will by no means be negatively affected.
Materials are certainly not smarter than their installers!!!
(After more than 20 years of installation work and over 10 years of airtightness testing, I have seen enough sealing and insulation disasters...!)
While you can believe (well-intended) half-truths from friends, acquaintances, neighbors, and forum users, I would rather hire professionals with the necessary knowledge and experience to find an optimal solution based on the actual local conditions... even if it costs a few euros. At least they are also liable for their statements or executed services.
Best regards from Erfurt
A
AallRounder2 Feb 2010 17:15Hello Maik,
perhaps you could kindly share here in the forum how your project was inspected by the local professional and then carried out. No one has questioned that in your case this is the only reasonable approach.
I hope, in any case, that both the (well-intentioned) “half-truths” and the (well-intentioned) cited general definitions and guidelines from construction literature have been helpful to you in some way.
Good luck!
perhaps you could kindly share here in the forum how your project was inspected by the local professional and then carried out. No one has questioned that in your case this is the only reasonable approach.
I hope, in any case, that both the (well-intentioned) “half-truths” and the (well-intentioned) cited general definitions and guidelines from construction literature have been helpful to you in some way.
Good luck!
A professional was here, and it was agreed that the floorboards would remain in place.
The setup is as follows:
A vapor-permeable airtight membrane is installed over the floorboards (the airtight membrane allows moisture to pass through),
followed by 200mm (8 inches) of insulation on top (not intended to be walked on).
Best regards
Maik
The setup is as follows:
A vapor-permeable airtight membrane is installed over the floorboards (the airtight membrane allows moisture to pass through),
followed by 200mm (8 inches) of insulation on top (not intended to be walked on).
Best regards
Maik