Planning to build some non-load-bearing interior walls in the basement with 90mm lightweight concrete blocks. There will be two door openings where I intend to place lightweight concrete beams. However, I'm now reading the manufacturer's instructions about a bearing support dimension of at least 250mm. The text is general, and I'm not sure if it varies between different lengths/widths, load capacities, etc.
In my case, I was thinking that one of the door openings would be directly against the opposite wall (see attachment), which would provide a bearing support of 90mm, which sounds weak compared to the manufacturer's instructions. One consolation is that it’s likely only one row of masonry blocks will be placed on the beam. The beam’s own weight is 18Kg, and with one row of masonry blocks on top, it becomes 16Kg on the beam.
The beam’s load capacity is 14 kN/lpm. The blocks' compressive strength is 3 N/mm², category 1.
Do you think it would work, or are there other alternatives that might be more suitable? Like casting a beam in place or bringing down a tension rod from the concrete ceiling that goes through the beam along with a flat iron + nut as a complement to the short support?
The last resort is to frame up the wall, but it feels wrong in an old basement; avoiding that as much as possible.
EDIT:
Here's what Weber says about their lightweight concrete beams:
EXECUTION
Leca Beam is laid with the marked side up in mortar
on the undamaged bearing support with a support length of
at least 250 mm. For smaller loads, the support length
can be reduced in consultation with a designer.
So the question then becomes what a smaller load is and how far you can go on 90mm...
In my case, I was thinking that one of the door openings would be directly against the opposite wall (see attachment), which would provide a bearing support of 90mm, which sounds weak compared to the manufacturer's instructions. One consolation is that it’s likely only one row of masonry blocks will be placed on the beam. The beam’s own weight is 18Kg, and with one row of masonry blocks on top, it becomes 16Kg on the beam.
The beam’s load capacity is 14 kN/lpm. The blocks' compressive strength is 3 N/mm², category 1.
Do you think it would work, or are there other alternatives that might be more suitable? Like casting a beam in place or bringing down a tension rod from the concrete ceiling that goes through the beam along with a flat iron + nut as a complement to the short support?
The last resort is to frame up the wall, but it feels wrong in an old basement; avoiding that as much as possible.
EDIT:
Here's what Weber says about their lightweight concrete beams:
EXECUTION
Leca Beam is laid with the marked side up in mortar
on the undamaged bearing support with a support length of
at least 250 mm. For smaller loads, the support length
can be reduced in consultation with a designer.
So the question then becomes what a smaller load is and how far you can go on 90mm...
Last edited:
3 N/mm2 corresponds to approximately 30 kg/cm2. A support of 9x9 cm can therefore handle a bearing pressure of 81x30 = 2430 kg. So it should not be a problem.
Thank you!
If I had stacked everything vertically on these 9x9, would the surface pressure amount to the beam's weight plus 16Kg for the wall blocks? Or is the pressure calculated differently?
Could there be other parameters that make the support unsuitable? Like if the reinforcement is set 50mm into the beam, etc.?
If I had stacked everything vertically on these 9x9, would the surface pressure amount to the beam's weight plus 16Kg for the wall blocks? Or is the pressure calculated differently?
Could there be other parameters that make the support unsuitable? Like if the reinforcement is set 50mm into the beam, etc.?
A bit simplified, you take the total load on the beam (including its own weight) and divide by two to get the load on each support. Then, if you divide the support load by the support area, you get the pressure. I am not aware of any other parameters related to the execution of the lecabalk. Obviously, the support should have a certain minimum length so that the beam doesn't slip off, but there is likely no risk of that here. The beam has an insignificant load. The maximum load of 14 kN/m means about 1400 kg per 1 meter, which is quite a lot more.