Marcinho14053 Nov 2016 19:43Hello everyone,
I am planning to rebuild the floor of our older house.
The floor itself, meaning the basement ceiling, consists of 12 cm (5 inches) thick B 160 reinforced concrete. On top of that, 6x8 cm (2.4x3.2 inches) squared timbers were laid floating, and wooden floorboards were nailed on.
I have now completely removed the old wooden structure. However, since I have two extensions on the house, there is a height difference of almost 11 cm (4.3 inches) compared to the screed in the extensions.
Leveling with new screed is not an option due to structural and cost reasons.
My planned new build-up is as follows:
- Perimeter insulation strip along the walls
- (new) 6x8 cm (2.4x3.2 inches) squared timbers laid floating
- 22 mm (0.9 inches) OSB 3 board
The main question I have now is whether I should also lay the OSB boards floating or screw them down and glue tongue and groove joints? I want to avoid creaking noises and have already received many different recommendations.
Has anyone here perhaps already carried out a similar build-up or has any other tips?
Thanks in advance.
Kind regards,
Marc
I am planning to rebuild the floor of our older house.
The floor itself, meaning the basement ceiling, consists of 12 cm (5 inches) thick B 160 reinforced concrete. On top of that, 6x8 cm (2.4x3.2 inches) squared timbers were laid floating, and wooden floorboards were nailed on.
I have now completely removed the old wooden structure. However, since I have two extensions on the house, there is a height difference of almost 11 cm (4.3 inches) compared to the screed in the extensions.
Leveling with new screed is not an option due to structural and cost reasons.
My planned new build-up is as follows:
- Perimeter insulation strip along the walls
- (new) 6x8 cm (2.4x3.2 inches) squared timbers laid floating
- 22 mm (0.9 inches) OSB 3 board
The main question I have now is whether I should also lay the OSB boards floating or screw them down and glue tongue and groove joints? I want to avoid creaking noises and have already received many different recommendations.
Has anyone here perhaps already carried out a similar build-up or has any other tips?
Thanks in advance.
Kind regards,
Marc
That's funny. I had exactly the same construction and now face the same question. The old floorboards and panels are removed, and I want to rebuild the floor structure as well.
I planned to use 4x6 timber joists, with leveling fill in between, and then glue and screw tongue-and-groove OSB boards. According to my carpenter, this should help prevent creaking. Before installation, the boards are supposed to stay inside the house for 24 hours to acclimate to the temperature.
What are the drawbacks of using Fermacell boards? Are you planning to install tiles on the OSB boards? At what height should the edge insulation strips be placed? I wasn’t sure if that is mandatory.
Best regards, jan
I planned to use 4x6 timber joists, with leveling fill in between, and then glue and screw tongue-and-groove OSB boards. According to my carpenter, this should help prevent creaking. Before installation, the boards are supposed to stay inside the house for 24 hours to acclimate to the temperature.
What are the drawbacks of using Fermacell boards? Are you planning to install tiles on the OSB boards? At what height should the edge insulation strips be placed? I wasn’t sure if that is mandatory.
Best regards, jan
Marcinho14054 Nov 2016 20:26Hello Jan,
Finally, I find someone who shares the same issue. The problem, as with most DIY questions, is that if you ask three people, you get five different answers.
A drywall installer once told me that screwing the panels in can actually cause creaking noises because the wood can no longer move naturally, and the expansion works against the fixed points created by the screws.
There are two reasons why I’m against using Fermacell boards: first, the cost, and second, my planned large rafter spacing of 62.5cm (25 inches) in the substructure to match the size of mineral wool partition boards for insulation. Tiles will only be installed in the kitchen, where the rafter spacing will be reduced, reinforcement mesh will be applied, and highly flexible adhesive used, along with small-format tiles, so everything should work well there.
I plan to install the edge insulation strip so that it extends above the OSB subfloor and then trim it flush. Is this the correct method? I’m not sure, but it seems like the most reasonable approach for achieving decoupling.
Finally, I find someone who shares the same issue. The problem, as with most DIY questions, is that if you ask three people, you get five different answers.
A drywall installer once told me that screwing the panels in can actually cause creaking noises because the wood can no longer move naturally, and the expansion works against the fixed points created by the screws.
There are two reasons why I’m against using Fermacell boards: first, the cost, and second, my planned large rafter spacing of 62.5cm (25 inches) in the substructure to match the size of mineral wool partition boards for insulation. Tiles will only be installed in the kitchen, where the rafter spacing will be reduced, reinforcement mesh will be applied, and highly flexible adhesive used, along with small-format tiles, so everything should work well there.
I plan to install the edge insulation strip so that it extends above the OSB subfloor and then trim it flush. Is this the correct method? I’m not sure, but it seems like the most reasonable approach for achieving decoupling.
I also find Fermacell too expensive compared to OSB. That’s why OSB is my choice at the moment. Are you planning to put mineral wool insulation between the joists?
I wanted to fill the Fermacell leveling compound to provide both insulation and a larger support area for the boards.
The downside of the compound is, again, the price.
In our case, this construction needs to be done in the hallway, wardrobe, and kitchen. Tiles will be installed on top everywhere. The tiler said he definitely needs a decoupling mat, which also adds to the cost.
I wanted to fill the Fermacell leveling compound to provide both insulation and a larger support area for the boards.
The downside of the compound is, again, the price.
In our case, this construction needs to be done in the hallway, wardrobe, and kitchen. Tiles will be installed on top everywhere. The tiler said he definitely needs a decoupling mat, which also adds to the cost.
All those who complain about "the money" regarding this and similar topics should ask themselves what they actually want.
There is no such thing as "too expensive." Every necessary construction method simply has its price. "Necessary" in this case means that you can also build in other ways, but you must accept the disadvantages of the chosen method.
For example, I cannot complain that mineral wool insulation under the precast screed slab involves costs. Yes, it is possible to do without it, but then you won’t have any thermal or sound insulation (which is, however, a questionable effort in timber construction).
Of course, I can also skip the separating layer beneath a dry fill.
That would save roughly 24.30€ per room but would lead to unpleasant problems on the floor below.
These examples could go on endlessly.
There are always several options for a proper build-up. But even the cheapest (still functional) solution involves costs.
The 11cm (4.3 inches) height difference that "Marcinho1405" mentioned as the starting point can simply be equalized by applying a vapor-open separating layer on the existing floorboards, which must be checked for loose floorboards, and by leveling the height over guides with a binder-containing fill so that a 19mm (0.75 inches) wood chipboard layer—well glued at the joints—can be installed as the finished usable surface, or alternatively a suitable load distribution based on a floating gypsum board layer.
Those who do not want or cannot spend money must live with the conditions provided on site.
------------------------------------------------
Regards, KlaRa
There is no such thing as "too expensive." Every necessary construction method simply has its price. "Necessary" in this case means that you can also build in other ways, but you must accept the disadvantages of the chosen method.
For example, I cannot complain that mineral wool insulation under the precast screed slab involves costs. Yes, it is possible to do without it, but then you won’t have any thermal or sound insulation (which is, however, a questionable effort in timber construction).
Of course, I can also skip the separating layer beneath a dry fill.
That would save roughly 24.30€ per room but would lead to unpleasant problems on the floor below.
These examples could go on endlessly.
There are always several options for a proper build-up. But even the cheapest (still functional) solution involves costs.
The 11cm (4.3 inches) height difference that "Marcinho1405" mentioned as the starting point can simply be equalized by applying a vapor-open separating layer on the existing floorboards, which must be checked for loose floorboards, and by leveling the height over guides with a binder-containing fill so that a 19mm (0.75 inches) wood chipboard layer—well glued at the joints—can be installed as the finished usable surface, or alternatively a suitable load distribution based on a floating gypsum board layer.
Those who do not want or cannot spend money must live with the conditions provided on site.
------------------------------------------------
Regards, KlaRa
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