Insitu Padstone on cavity wall!

[STORYTELLER]

I'm guessing that the designer of it shoved its end out into the new extension to avoid the padstone jutting into the interior on a nib wall.

Seems weird to me. That will be cold and potentially damp.

i specified to use the new side wall of extension to avoid having to install a steel post and associated foundation... But I didn't know SE was then going to fill the cavity with a big poured padstone... I'd have moved inner wall back by 50mm if it would have allowed steel to sit on it without need to bridge cavity... BUT... even if steel hadn't gone out the side, the SE still specified that big padstone that bridged the cavity!

 

[STORYTELLER]

I would have made the extension half a brick wider, then made that section of the inner leaf 9" wide under the steel by widening that part of the wall into the room. Then the steel wouldn't have crossed the new cavity so wouldn't be bridging cold and damp and would also be fully supported by brickwork to the ground, rather than sitting on a pad that's 50% over fresh air.

Perhaps you could have even extended it further so eliminated the need for any nib wall at all within the original house.

But... the original house doesn't have a cavity anyway, so it's all a bit academic.

is a good point.. but I didn't realise SE would bridge the cavity like that or I would have done... but time as getting tight.. but is still not clear why it had to bridge cavity at all. But thermally... the adjacent bit of house side wall is 1930's solid wall... and is now part of the open room... so infinitely more heat is being lost there anyway... Also, the SE had a scheme where still didn't protrude... may be more nervous... but the pad still bridged cavity!

 

[STORYTELLER]

I'm guessing that he's not banking on the existing foundations being man enough on their own. So he's gaining some additional support from the new masonry (250mm of additional steel and 400mm of additional padstone), in order to satisfy the calc's criteria.

yes exactly - I didn't want to assume foundations were OK, then have to re-design after demolition of the old rear of kitchen... (if they dug down and found foundation issues.. but as it turned out, there is basically hardly any foundation... then sheet rock within about 80cm.) and was trying to avoid cost/hassle of steel post... tho now...... I'm not sure. The full 250 wasn't completely needed... In fact I asked the builder to reduce to 100, got it OK'd by SE, then the builder just order and installed the 250 length steel anyway... f£$%%^£%£. OH and the steel guys just installed the UC...and it's not plumb!