Can someone check my padstone calculations for a beam please

[harrypotter]

I've followed a series of videos (here) on how to find the correct size beam required for removing a 6m wall in my bungalow to open it up into a new extension. Following the video I'm pretty confident in the calculations, but I need to see about a padstone.

Now onto seeing if I need a pad stone for the beam:
- Beam end loads are 29 kN either side.
- Beam will sit on the block by 150 mm
- Concrete block width is 100 mm
- Total area of bearing is 150 mm x 100 mm = 15,000 mm^2
- Load on bearing = 29 kN * 1000 / 15,000 mm^2 = 1.9 N/mm^2

Does this mean regular 7N block would be more than adequate? I assume the 7N refers to 7N/mm^2.

Thanks.

 

[George_engineer]

You should speak to an engineer... removing walls is not just about the beam and padstone, you need to consider the structure's lateral stability and the load bearing capacity of the supporting walls and foundations.

Removing 6m of wall is a good chunk of any house and checking it's safe should be done with professional help. Doesn't mean you can't DIY the work, though.

 

[Deluks]

You should speak to an engineer...

 

[23vc]

You’d need an SE’s calcs anyway for building control

 

[harrypotter]

The 6m of former external wall to be removed is actually made up of 4m of block and a 2m wide patio (fitted when built). The new external wall for the extension will also be made up of 4m of block and 2m of patio door, so there's no concern about losing lateral stability.

Regarding the loads on the foundation, this is a bungalow so I can't imaging this would be a problem.

 

[^woody^]

Blocks will typically fail bearing shear even if adequate for the bearing capacity.