Padstones sufficient?

[NotAScooby22]

Hi all,

Hoping you can ease my worried mind. We’ve had the ground floor back of the house removed to open up the kitchen. I trust my builder, and his communication is good - but I’ve only known him 5 weeks and I’m placing at minimum my house in his hands, and at most the lives of my children.

We had a structural engineer do the calcs. It was a cavity wall being removed, so it required two 254x146x43 steels (6.9m long) bolted together - with the calcs saying for these to rest on a 200mm (ish) nib of the old wall with two x PAD 02 (perpendicular to the steel - ie. Padstones bridging the cavity).

The builder however, has removed the nib entirely, and rebuilt the wall flush out of high density blockwork. It’s partially toothed into the existing wall, with a single padstone on top for the steels.

I agree with the builder that the new blockwork is stronger than what existed previously - and much more visually pleasing than a nib - but I worry about the weight distribution.

It’s a 2 storey semi detached, with an additional loft conversion. So the steels (and single skin walls with a padstone at each end) are supporting a storey of cavity wall, a soon to be cut on pitched roof and a dormer.

Building control will be due to visit, but I don’t know when.

I’ve attached some pictures, and look forward to being told everything is fine

Thanks

 

[noseall]

Hi all,

Hoping you can ease my worried mind. We’ve had the ground floor back of the house removed to open up the kitchen. I trust my builder, and his communication is good - but I’ve only known him 5 weeks and I’m placing at minimum my house in his hands, and at most the lives of my children.

We had a structural engineer do the calcs. It was a cavity wall being removed, so it required two 254x146x43 steels (6.9m long) bolted together - with the calcs saying for these to rest on a 200mm (ish) nib of the old wall with two x PAD 02 (perpendicular to the steel - ie. Padstones bridging the cavity).

The builder however, has removed the nib entirely, and rebuilt the wall flush out of high density blockwork. It’s partially toothed into the existing wall, with a single padstone on top for the steels.

I agree with the builder that the new blockwork is stronger than what existed previously - and much more visually pleasing than a nib - but I worry about the weight distribution.

It’s a 2 storey semi detached, with an additional loft conversion. So the steels (and single skin walls with a padstone at each end) are supporting a storey of cavity wall, a soon to be cut on pitched roof and a dormer.

Building control will be due to visit, but I don’t know when.

I’ve attached some pictures, and look forward to being told everything is fine

Thanks

Take a phot of it and email or text it to the SE.

I always confer with the SE before doing anything different to what is specified, even if I think it's an improvement.

My thoughts are that all the masonry below that beam would need a re-build and fully tied into the existing. We often have to re-build the masonry beneath a bearing in 7n blockwork, but fully tied in on every course....

shazzabeam10.jpg

• noseall
• 31 Mar 2025

 

[stevie888]

Get BC to inspect soonest and press the SE for comments. If both OK then happy days.

What you have is arguably better than the oiginal BUT I am surprised that such a small nib was deemed acceptable.

Toally agree with Noseall: ask before deviating from approved drawings, especially with structural stuff.

 

[NotAScooby22]

When you say you’re surprised about the small nib, do you mean the original 200mm, or the current 100mm wall?

Thanks

 

[stevie888]

Original.

There are 2 issues: one is the load nearing capacity of the pier, the second is the buttressing effect of the pier on the adjoining walls.

 

[NotAScooby22]

Ok thank you, so I may have misremembered the 200mm aspect- it was two Padstones side by side (so 200mm there) but may have been more like 500mm as a total nib.

Either way the nib no longer remains and it’s all resting on a single 100mm Padstone on a single skin wall.

The builder is confident, but we’d like to live long lives in this house, and I’d like to know it’ll last 50 years.

 

[NotAScooby22]

Take a phot of it and email or text it to the SE.

I always confer with the SE before doing anything different to what is specified, even if I think it's an improvement.

My thoughts are that all the masonry below that beam would need a re-build and fully tied into the existing. We often have to re-build the masonry beneath a bearing in 7n blockwork, but fully tied in on every course....

shazzabeam10.jpg

• noseall
• 31 Mar 2025

Thank you Noseall, I have sent photos to the SE and will hopefully hear what he says soon. I’ll also try and get in touch with BC - obviously if they’re both happy then I’ll feel better. Thanks again

 

[Dereekoo]

From a beam load distributed on to 2nr 100mm walls which then dissipates each half of this load downwards/outwards at 45 degrees down each wall (due to corbelling effect of brickwork) to a load that rests on what basically looks like a vertical 100mm thick column with the odd block passing some load into the side walls ?? Defo for the SE to approve or not as he will know what design parameters/loads he is working to. Please update us on his deliberations.

 

[^woody^]

Many engineers leave poxy nibs for no reason. I've not left a nib since 1984 and good riddance to them.

Looks like the builder has made a good effort to make a better job, but yes strictly it should be confirmed as suitable by the engineer - and that does not mean just saying "put a nib back".