Size/specification of padstone



I've just realised from the specifications and drawings of my single story extension (there is a 5m clear span requiring a 5.4m 203x133 30kg/m UB with 10mm plate), that there is no mention of padstones for the RSJ.

Before I go back to the man who did the drawings few years ago, is this something I have to get calculated? I don't know padstones so don't know if they come in different load ratings or size requirements or whether when my builder starts it's simply a case of get a padstone of type PAD12 (from a random google search) 440 x 215 x 102, for example.

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Rang the BC as I had to arrange a site visit and he said if I'm using dense blocks rather than thermalite then there's no need, but either way, a block sized padstone will be more than sufficient.

Is the UB over the bi-folds so only supporting the extension roof, or is it supporting the existing house wall?
My last extension had a similar sized beam over 5M that the SE said would be fine on the standard 3.5N blocks I was using. I put it on 7N blocks to make myself feel better.
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As long as the reaction at the end of the beam divided by the area of the steel plate is less than the compressive strength of the blocks including all the safety factors then there's no need. I was surprised we didn't need one for the new beam supporting all of upstairs and the roof where it rested on the inner leaf only, but apparently it's fine.
yes, it's a single story extension (7m) with 5m bifolds in the middle and the rsj just taking the load of the roof. The rsj will be 200mm over on each side.

Luckily I rang him because my brickies wanted me to change thermalite to dense blocks as they hate them but the BC said that would only give a k value of 3 not 2.8 so he told me to change rockwool to drytherm 34 or better and all will be good. So many things to know....

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