ᐅ Leave existing wooden floor in bathroom without additional layers?
Created on: 8 May 2017 16:17
A
Altbau1930
Hello everyone, I’m new here (please forgive any beginner mistakes).
We are taking over a house from the 1930s from relatives, which is in good condition and has always had any necessary repairs done promptly.
The house has two floors plus a basement. The ceilings on the first and second floors are wooden, so the original floorboards are still in place there. Their condition is good, but of course we need to sand and seal them all again to make them look nice.
On the first floor, we want to build a bathroom in a room that has so far been used “conventionally” (office/children’s room, etc.). The necessary water pipes can be easily routed from the next room, and the entire house’s electrical system will be updated by a professional company anyway.
In some instructional videos, I saw that you can build a bathroom on a wooden floor with various floor build-ups (impact sound insulation, OSB boards, Fermacell boards, sealants, possibly tiles). What concerns me is the height of the entire structure, which would end up about 100mm (4 inches) higher than the original floor. Also, there would be a small step at the transition. Additionally, the extra load on the ceiling should be kept as low as possible.
Is it not possible to sand and treat the original floor (so it looks nice in the end) but also seal it to install the bathroom there? Of course, no moisture should penetrate the floor later, that’s obvious. The walls will be tiled.
Does anyone have tips for my plan, or is this simply not feasible? How have you solved similar issues?
Thanks in advance!
We are taking over a house from the 1930s from relatives, which is in good condition and has always had any necessary repairs done promptly.
The house has two floors plus a basement. The ceilings on the first and second floors are wooden, so the original floorboards are still in place there. Their condition is good, but of course we need to sand and seal them all again to make them look nice.
On the first floor, we want to build a bathroom in a room that has so far been used “conventionally” (office/children’s room, etc.). The necessary water pipes can be easily routed from the next room, and the entire house’s electrical system will be updated by a professional company anyway.
In some instructional videos, I saw that you can build a bathroom on a wooden floor with various floor build-ups (impact sound insulation, OSB boards, Fermacell boards, sealants, possibly tiles). What concerns me is the height of the entire structure, which would end up about 100mm (4 inches) higher than the original floor. Also, there would be a small step at the transition. Additionally, the extra load on the ceiling should be kept as low as possible.
Is it not possible to sand and treat the original floor (so it looks nice in the end) but also seal it to install the bathroom there? Of course, no moisture should penetrate the floor later, that’s obvious. The walls will be tiled.
Does anyone have tips for my plan, or is this simply not feasible? How have you solved similar issues?
Thanks in advance!
A
Altbau193012 May 2017 15:35Thank you for the answers, it was just a thought! However, I realize that we can’t avoid building a proper subfloor on the wooden floor in order to install tiles. I wanted to avoid that, but it will create a small "step" at the entrance of the bathroom. But okay, we will have to live with that later.
If I have understood correctly: impact sound insulation on the original wooden floorboards, then 2 layers of OSB boards (glued together), then a kind of rubber membrane for sealing (applied like paint), followed by tile adhesive and then the tiles. Is that correct so far? I think that could result in a total height of at least 7mm (0.3 inches).
The most important thing is that the subfloor remains rigid so the tiles stay firmly in place and do not crack due to movement of the wooden floor.
If I have understood correctly: impact sound insulation on the original wooden floorboards, then 2 layers of OSB boards (glued together), then a kind of rubber membrane for sealing (applied like paint), followed by tile adhesive and then the tiles. Is that correct so far? I think that could result in a total height of at least 7mm (0.3 inches).
The most important thing is that the subfloor remains rigid so the tiles stay firmly in place and do not crack due to movement of the wooden floor.
Hello questioner,
If the old floorboards are to be kept without causing problems later with the installation height, then that is fine.
The old floorboards, which must be checked beforehand for firm attachment and re-secured if necessary, will be covered with a fleece underlay, serving as an "anti-creak" layer. However, this underlay must not have a polyethylene (PE) backing film, so do not use painter’s fleece!
The entire system must remain vapor-permeable. Before any further work, check the levelness with a spirit level at least 2 meters (6.5 feet) long.
Even under load, there must be no deflection!
On top of this fleece layer, install a layer of 22 mm (7/8 inch) tongue-and-groove OSB boards, making sure to glue them well!
The entire OSB surface is then coated twice with an alternative waterproofing membrane (a suitable, two-component liquid plastic).
At floor-to-wall transitions, a sealing tape must be firmly and tightly integrated into this waterproofing layer. Prefabricated corner pieces are available for inside and outside corners.
Apply a primer on the OSB boards (acting as a bonding bridge), then fix the tiles with a flexible adhesive. Tiles on wooden subfloors should not exceed dimensions of 30 cm x 30 cm (12 inches x 12 inches), otherwise there is a risk of cracking even with slight floor deflections.
This way, the work will turn out well!
-------------------------------------------
Best regards and good luck: KlaRa
If the old floorboards are to be kept without causing problems later with the installation height, then that is fine.
The old floorboards, which must be checked beforehand for firm attachment and re-secured if necessary, will be covered with a fleece underlay, serving as an "anti-creak" layer. However, this underlay must not have a polyethylene (PE) backing film, so do not use painter’s fleece!
The entire system must remain vapor-permeable. Before any further work, check the levelness with a spirit level at least 2 meters (6.5 feet) long.
Even under load, there must be no deflection!
On top of this fleece layer, install a layer of 22 mm (7/8 inch) tongue-and-groove OSB boards, making sure to glue them well!
The entire OSB surface is then coated twice with an alternative waterproofing membrane (a suitable, two-component liquid plastic).
At floor-to-wall transitions, a sealing tape must be firmly and tightly integrated into this waterproofing layer. Prefabricated corner pieces are available for inside and outside corners.
Apply a primer on the OSB boards (acting as a bonding bridge), then fix the tiles with a flexible adhesive. Tiles on wooden subfloors should not exceed dimensions of 30 cm x 30 cm (12 inches x 12 inches), otherwise there is a risk of cracking even with slight floor deflections.
This way, the work will turn out well!
-------------------------------------------
Best regards and good luck: KlaRa
A
Altbau193013 May 2017 16:29Thank you for your detailed explanation, KlaRa!
That already gives us a starting point, and we are omitting bathtubs in the bathrooms, which reduces the weight load in this regard. A full bathtub including materials and cladding/tiles can easily weigh around 250kg (550 lbs), which could cause the floorboards to give way.
That already gives us a starting point, and we are omitting bathtubs in the bathrooms, which reduces the weight load in this regard. A full bathtub including materials and cladding/tiles can easily weigh around 250kg (550 lbs), which could cause the floorboards to give way.
A
Altbau193013 May 2017 17:34What do you think of this Lux-Elements floor construction system?
Unfortunately, I can’t provide any information about the subfloor – only that terrazzo floors are quite common in kitchens and bathrooms in older buildings. In our case (a house built in 1903), we had linoleum in the kitchen (and the bathroom that was later added to the apartment) as well as terrazzo in the old toilet area (located on the half-landing). In a house from the mid to late 1920s, I know of terrazzo being used in the bathroom, kitchen, and pantry. In my opinion, when floor tiles are smaller than the wall tiles, it doesn’t look bad at all.
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https://www.instagram.com/11antgmxde/
https://www.linkedin.com/company/bauen-jetzt/
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Altbau193013 May 2017 18:54The special aspect of our project is that we want to install a bathroom in a room that was previously not a wet room. As mentioned, the room has wooden floorboards, on which the new floor structure for the bathroom will be built.
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