Hello! I need more advice, preferably from someone who is a designer, on whether what I wish to do is possible. Extremely grateful for advice.
a) Do I need to reinforce my floor structure to achieve my purpose, or can I proceed without reinforcement?
b) If I must reinforce: Is it possible to reinforce a siporex (lightweight concrete) floor structure with, for example, a reinforced slip layer (self-leveling compound) or do I need to reinforce the floor from below?
Conditions:
According to the technical drawing, it is stated that the floor structure, unless otherwise specified, is constructed of 200mm lightweight concrete elements BE230. In addition to another note on one of the drawings, which states that the floor structure can support 2.3 kN unless otherwise specified, I interpret this as a BE230 element can support 230kg/m2. The span is approximately 3.9 meters, and the floor structure rests on a foundation wall (basement walls) of 250mm siporex above a concrete footing, edge-reinforced with a centrally reinforced slab.
Purpose:
To install a tiled floor in the kitchen. Self-leveling compound approximately 15mm (25kg/m2), adhesive/grout, etc., and stone give approximately 53 kg/m2. Additionally, there will be a kitchen.
a) Do I need to reinforce my floor structure to achieve my purpose, or can I proceed without reinforcement?
b) If I must reinforce: Is it possible to reinforce a siporex (lightweight concrete) floor structure with, for example, a reinforced slip layer (self-leveling compound) or do I need to reinforce the floor from below?
Conditions:
According to the technical drawing, it is stated that the floor structure, unless otherwise specified, is constructed of 200mm lightweight concrete elements BE230. In addition to another note on one of the drawings, which states that the floor structure can support 2.3 kN unless otherwise specified, I interpret this as a BE230 element can support 230kg/m2. The span is approximately 3.9 meters, and the floor structure rests on a foundation wall (basement walls) of 250mm siporex above a concrete footing, edge-reinforced with a centrally reinforced slab.
Purpose:
To install a tiled floor in the kitchen. Self-leveling compound approximately 15mm (25kg/m2), adhesive/grout, etc., and stone give approximately 53 kg/m2. Additionally, there will be a kitchen.
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Best answer
The problem is that the Siporex factory no longer exists, and it is difficult to obtain relevant technical documentation. My own experience with lightweight concrete is limited and dates back quite some time, so I've forgotten a lot. Based on the information you provided, we can still have a theoretical discussion. Assuming that the floor elements can withstand a distributed load of 230 kg/m2 (which I’m not certain about), we can deduct 200 kg/m2 as what is known as the useful load, i.e., all furniture and people, which is the norm for a standard residence. This leaves 30 kg/m2 in available load while you want to increase the dead weight by 53 kg/m2. The result is a deficit of 23 kg/m2. Do you need to reinforce the floor for this reason? No, a ten percent deviation should not make a difference. However, you can still make sure the kitchen furnishings are a bit lighter. Avoid chipboard in the frames and granite countertops, for example.
You cannot reinforce a floor from above; it must be done with, for example, a beam on the underside.
You cannot reinforce a floor from above; it must be done with, for example, a beam on the underside.
Hello!
Thanks for the response! I have studied the issue and understood the connection, so I thought I would try to share if others encounter obstacles.
In the 1970s-80s, a floor slab in a house was calculated to have an operational load (i.e. what you do in the space) of 150kg/m2. Additionally, 50kg/m2 was added for partitions (mounted above the slab) and 30kg/m2 for flooring material. This results in a total design load of 230kg/m2, which roughly corresponds to 2.3kN/m2 (hence the marking BE230). BE400, which was the next level of element (handles a design load of 400kg/m2), was used, for example, in bathrooms and at points where large point loads might occur.
In 2017, it is now the case that the operational load is set to 200kg/m2, the wall to 50kg/m2, and the floor to 30kg/m2, which gives a total of 280 kg or about 2.8 kN/m2, which is why normal concrete floor slabs today are marked as 2.8.
So in my case, where I do not have any partitions, the result is instead 230kg/m2 minus about 55kg/m2 >> about 175 kg/m2 remaining for operational load (useful load). I have concluded just like you that I do not need to reinforce the floor slab but will avoid screeding just under the kitchen island (especially with a wood frame and stone countertop (even if light)).
It is recommendable for those who wish to find the lightweight concrete handbook from 1993. There is a PDF online concerning just floor slabs. The limit for the floor slab, as I understand, is 1.3 times the load capacity, i.e. 300kg/m2.
I hope someone else finds the information useful, and thank you justusandersson for validating what I understood.
Thanks for the response! I have studied the issue and understood the connection, so I thought I would try to share if others encounter obstacles.
In the 1970s-80s, a floor slab in a house was calculated to have an operational load (i.e. what you do in the space) of 150kg/m2. Additionally, 50kg/m2 was added for partitions (mounted above the slab) and 30kg/m2 for flooring material. This results in a total design load of 230kg/m2, which roughly corresponds to 2.3kN/m2 (hence the marking BE230). BE400, which was the next level of element (handles a design load of 400kg/m2), was used, for example, in bathrooms and at points where large point loads might occur.
In 2017, it is now the case that the operational load is set to 200kg/m2, the wall to 50kg/m2, and the floor to 30kg/m2, which gives a total of 280 kg or about 2.8 kN/m2, which is why normal concrete floor slabs today are marked as 2.8.
So in my case, where I do not have any partitions, the result is instead 230kg/m2 minus about 55kg/m2 >> about 175 kg/m2 remaining for operational load (useful load). I have concluded just like you that I do not need to reinforce the floor slab but will avoid screeding just under the kitchen island (especially with a wood frame and stone countertop (even if light)).
It is recommendable for those who wish to find the lightweight concrete handbook from 1993. There is a PDF online concerning just floor slabs. The limit for the floor slab, as I understand, is 1.3 times the load capacity, i.e. 300kg/m2.
I hope someone else finds the information useful, and thank you justusandersson for validating what I understood.