Help sourcing the right size Padstones

[Oceans247]

Hi there,

My SE has specified the following padstones:

440 L x 100wd x 150dp Concrete Padstone
660 L x 100wd x 215dp Concrete Padstone
1200 L x 100wd x 215dp Concrete Padstone
880 L x 100wd x 215dp Concrete Padstone

I have searched the internet for several hours and I cannot find padstones in these dimensions.

Any guidance would be highly appreciated!

Cheers

 

[tony1851]

A quick way to get the right size is to cut down 6" x 4" and 9" x 4" concrete lintels to the required length - using a disc cutter. They have the advantage of reinforcement in the middle and are ideal for non-standard length padstones.
But why in the name of heaven do you need a 1200 long padstone!!?? What is the beam supporting?

 

[Oceans247]

A quick way to get the right size is to cut down 6" x 4" and 9" x 4" concrete lintels to the required length - using a disc cutter. They have the advantage of reinforcement in the middle.
But why in the name of heaven do you need a 1200 long padstone!!?? What is the beam supporting?

I think my SE is just playing it safe in case I want to add a further 8 stories to my 2 story mid terrace house.

Thank you for the tip about cutting down to size.

 

[Oceans247]

Sorry, I didn't actually answer your question. The 1200mm long padstone is supporting the middle floor beam for the new loft floor and also a post/column that is supporting the ridge beam that is also supporting the chimney stack.

 

[tony1851]

I understand roughly the load it is carrying, but 1200 is still verrrrrrrrrrry long.
Assuming a worst-case scenario of brickwork characteristic strength of 2.5N/mm² (very low!), a 1200 long padstone would be capable of sustaining a factored load of over 100Kn.
Can't somehow see a floor, chimney stack and ridge beam coming anywhere near that?
Certainly a belt-and-braces job!

 

[^woody^]

1200 is still verrrrrrrrrrry long

Wrong not long.

That's just a stupid size. I can't imagine for one moment that a proper engineer calculated that.

 

[Oceans247]

Wrong not long.

That's just a stupid size. I can't imagine for one moment that a proper engineer calculated that.

Well, that's reassuring.....

How can I challenge/question something like this... something I know nothing about?

 

[tony1851]

Just ask him - as a matter of interest, so to speak - what the load is on the 1200 padstone, and post back.

 

[^woody^]

Tell him Tony on the internet said he's a charlaton and there are not even 1200mm padstones on the Severn bridge, let alone for sale in Jewsons. Stop tripping and come down to earth.

 

[Oceans247]

LOL. Thanks guys. I might ask him in passing.

 

[garyo]

Has he given you the calcs to pass to your building control? Somewhere it should talk about the end reactions of the beams, and somewhere in there there must be an assumption on the compressive strength of the brickwork.

 

[Oceans247]

Has he given you the calcs to pass to your building control? Somewhere it should talk about the end reactions of the beams, and somewhere in there there must be an assumption on the compressive strength of the brickwork.

Hi there,

Yes I have a 150 page document with all the detailed calcs.

Can I ask, whats the issue with the oversized padstone, other than the hassle of installing it? The cost saving of a smaller padstone is negligible.

 

[garyo]

whats the issue with the oversized padstone

Purely inconvenience, in my view. The faff of chasing so much brick out to install it, and at 1200mm width you'd want a way of supporting the brickwork above, versus a 440 width where you can probably do it without support. You might also take the viewpoint that if this element of the design is bizarre, what else might be? If there's an error in a calculation it may be upstream, and you may have steels that are twice as large as they need to be too.

 

[Oceans247]

Purely inconvenience, in my view. The faff of chasing so much brick out to install it, and at 1200mm width you'd want a way of supporting the brickwork above, versus a 440 width where you can probably do it without support. You might also take the viewpoint that if this element of the design is bizarre, what else might be? If there's an error in a calculation it may be upstream, and you may have steels that are twice as large as they need to be too.

Thank you for your reply.

I do recall the SE commenting that the mortar was pretty soft. The bricks are also quite soft, yellow stocks.

 

[tony1851]

Yes I have a 150 page document with all the detailed calcs.