Maintaining the coursing above a steel beam

6 Jun 2007
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United Kingdom
I'd appreciate some advice please.

I'm building a two storey extension which is going OK and I'm approaching first floor level. There's a 2.4M opening which is spanned by a concrete lintel on the outer leaf and a steel universal beam set on padstones on the inner leaf (as per the SE's specification).

The concrete lintel is 140mm (2 brick courses) deep which is fine but, the steel beam is only 127mm deep. To maintain the coursing above the opening I'd like to keep the top of the lintel and beam at the same height (which would also give me some additional room for fitting the fire protection to the beam).

I'm looking for advice on the best way to make up the 13mm difference.
I've considered a couple of options ----

1) Lay a 3mm thick piece of slate on a 10mm mortar bed under the padstones.

2) Cut 62mm off the bottom off the padstones (I've already had them made) and lay an extra course of bricks below them.

Any thoughts?
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new padstones?

Aren't you allowed to site-cast your own padstones any more?
you can lay a 13mm mortar bed, no problem.

10mm is visually better for face brickwork, but not a regulated standard.
Thanks for the prompt responses.

I think I've confused everyone, I should have made it clear that I'll be left with the 13mm shortfall in height after I'd layed a 10mm mortar bed. The actual gap I'm trying to fill is 23mm without copromising the strength of the wall.

As for the padstones, that's probably down to my amateur status as a builder. I didn't realise I'd be allowed to cast my own, I thought the BCO would need to see some proof of the mix used. Now that I've had a few visits from the BCO I realise that this wouldn't be an issue. When this extension's finished I'm building another on the other side of the house so I might save a few bob and cast my own then.

Thanks for any further advice you can give.
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