Made a small sketch, hope you understand it 
You can find it at http://www.labbas.se/pics/reglar.jpg
The bathroom will be within the white dots.
The red are existing floor joists
The black are beams
The blue is a wall (should remain, resting on existing floor joists)
The distance between the existing floor joists is cc60 (even if it's different in my picture), these have a size of 170x45.
The beams have support every 1.5 m. They have a dimension of about 15x15 cm.
In this room, it will become a bathroom. I want to reinforce the floor to cc30.
These are the problems I have,
What size should I have for the new floor joists?
I've considered 220, but the problem is that they become much higher than existing ones. Alternatively, notching them for the beams (but then I lose load-bearing capacity, can this be reinforced?)
How do I solve the problem of not reaching the beam at the top as it is under another floor/room?
How does it seem to screw a larger dimension floor joist into a smaller floor joist (resting on all beams)? I assume the load-bearing capacity won't be greater than the smaller joist's dimension?
Grateful for any tips and ideas.
You can find it at http://www.labbas.se/pics/reglar.jpg
The bathroom will be within the white dots.
The red are existing floor joists
The black are beams
The blue is a wall (should remain, resting on existing floor joists)
The distance between the existing floor joists is cc60 (even if it's different in my picture), these have a size of 170x45.
The beams have support every 1.5 m. They have a dimension of about 15x15 cm.
In this room, it will become a bathroom. I want to reinforce the floor to cc30.
These are the problems I have,
What size should I have for the new floor joists?
I've considered 220, but the problem is that they become much higher than existing ones. Alternatively, notching them for the beams (but then I lose load-bearing capacity, can this be reinforced?)
How do I solve the problem of not reaching the beam at the top as it is under another floor/room?
How does it seem to screw a larger dimension floor joist into a smaller floor joist (resting on all beams)? I assume the load-bearing capacity won't be greater than the smaller joist's dimension?
Grateful for any tips and ideas.
30 cc is wise to have in a bathroom floor. But I don't understand why you should increase the dimension, does it flex in the middle of the joist? The span is very short, so a 170 mm joist shouldn't be a problem. I would have "nogged" joists next to the wall and then connected the new floor joists to it. If you then plan to have a chipboard and leveling compound, it will be by the book
Managed to reconsider and bought 170 studs. Had exactly the same thought as you. 😊
Can't say it's sagging at the moment; of course, if I stand and jump on a stud, it might flex a bit, but nothing I can feel.
In the worst case, I can put a support beam right under the wall. But I don't think it's needed with the floor chipboard and leveling compound.
You want to do a proper groundwork😛
Can't say it's sagging at the moment; of course, if I stand and jump on a stud, it might flex a bit, but nothing I can feel.
In the worst case, I can put a support beam right under the wall. But I don't think it's needed with the floor chipboard and leveling compound.
You want to do a proper groundwork😛
I would like to then develop the question to how long a span determines when the flexural stiffness becomes inadequate? The requirement for cc30 is somewhat dependent on the span and the floor. If we start with 22 mm flooring chipboard and cc60 according to the TS image, what is suitable to consider regarding noggings, the levelling compound, reinforcement, and thickness?
If you have a floor structure with cc60 that meets the basic requirements for bending stiffness for floor structures (which TS's floor structure surely does), one method is to use 22mm chipboard flooring, minimum 12mm self-leveling compound that is reinforced. Then you can lay tiles on the floor.
Okay, I think the previous speaker is right in this, that one then meets the requirements. But it is not uncommon to have 30 cc in the floor. Probably to have both belt and suspenders. Designers often draw in cc30 on drawings. I would have at least added a few extra studs, it doesn't take many minutes.
Reference for sufficient bending stiffness
A long experience of tried and tested solutions shows that the bending stiffness achieved with a c-distance of 300 mm between the beams and a 22 mm chipboard floor is reassuring so that the ceramic layer is not damaged. (Such a construction, however, also requires reinforced leveling compound to accommodate movements in the wood board, not primarily for bending stiffness.
Copied this from BKR.
A long experience of tried and tested solutions shows that the bending stiffness achieved with a c-distance of 300 mm between the beams and a 22 mm chipboard floor is reassuring so that the ceramic layer is not damaged. (Such a construction, however, also requires reinforced leveling compound to accommodate movements in the wood board, not primarily for bending stiffness.
Copied this from BKR.
Okay, I am familiar with what is in BKR.
This is from the section for floors, cc600 and self-leveling compound with reinforcement is fully sufficient:
5.7.2 Floors
Board structures on floors usually consist of
22 mm chipboard* on joists with c-spacing
between 300 and 600 mm. Wooden floors
require adaptation for a ceramic coating
so that it is not damaged by the wood material's
natural movements due to changes in humidity
and/or deflection of the wood material
between joists under floor load.
Regardless of c-spacing between joists, however
max. 600 mm, reinforcement of bending stiffness
between joists, and measures to prevent
moisture movements being transferred to the ceramic layer,
should be performed. Reinforcement can be done with leveling
compound according to the following example of
construction principle. Reinforcements with
equivalent effect can be achieved with other
construction methods according to the responsible designer/manufacturer.
This is from the section for floors, cc600 and self-leveling compound with reinforcement is fully sufficient:
5.7.2 Floors
Board structures on floors usually consist of
22 mm chipboard* on joists with c-spacing
between 300 and 600 mm. Wooden floors
require adaptation for a ceramic coating
so that it is not damaged by the wood material's
natural movements due to changes in humidity
and/or deflection of the wood material
between joists under floor load.
Regardless of c-spacing between joists, however
max. 600 mm, reinforcement of bending stiffness
between joists, and measures to prevent
moisture movements being transferred to the ceramic layer,
should be performed. Reinforcement can be done with leveling
compound according to the following example of
construction principle. Reinforcements with
equivalent effect can be achieved with other
construction methods according to the responsible designer/manufacturer.