Piers needed for Lintel, and sizing query

[RichTeaBiscuits]

Hi

I'm going to take out a wall between my kitchen and dining room as shown in the image below.

It is currently supporting the joists for the first floor (which run from left to right across the drawing), but no upstairs wall.

A few questions though, if anyone can advise, please?

1. Estimated RSJ size? I'll ask a structural engineer for a calculation, but wanted an idea for estimating cost.
2. Do I need to build piers at either end, or can I simply let the steel into the walls? (note I realise this may be tricky). The external wall is thermalite block, whereas the internal one adjacent to the stairs is concrete block.
3. I assume I'll need padstones?

Finally a question on the structural engineer... last year I knocked a door through into my garage conversion (the study on the floorplan), for which the BCO didn't ask for such calculations and was happy with the concrete lintel I installed. Are SE calcs really needed?

Cheers
Rich

 

[hotrod]

1. Depends on the span and dimensions - your detail doesn't show any.
2. See point 1 above.
3. Yes.

BCO's aren't generally concerned about calcs for openings <1000mm this is bread and butter stuff and an off the shelf concrete lintel will be passed no worries.

 

[RichTeaBiscuits]

Doh! Yes, I can see how some dimensions might help

The maximum span is 3050mm, which assumes no piers. The internal leaf of the external wall is 100mm thermalite, and the internal wall adjacent to the stairs is 100mm concrete block.

 

[Static]

Prob can assume it to be around the mid range 152x152UC steel.. for costing..
Probably would need to leave a pier at the external wall end (or rebuild a small eng brick one)
Yes, better to let someone else take the responsibility for the design as they are insured for it..

 

[^woody^]

For costing there is only going to be a few £s difference, and a 7x4 or 8x4 will do, and I would suggest will look better than a fat 6" beam, and would be about £100

But it depends if that partition wall really is 9" thick as it looks like on the plan and whether the joist have enough lap

The beam should be able to sit on a 100mm bearing on the outer wall without a pier, even though it is near to the door reveal

You don't need padstones, there are other options if the existing wall is not suitable - engineering bricks, a concrete lintel, steel plate etc

You do would not have needed calcs for the doorway and standard lintel, and in fact some councils will not require calcs for this type of work ..... however you still need to be sure that the beam and supports are designed to be adequate

 

[RichTeaBiscuits]

Thanks Woody. The wall is around 6" overall (with plasterboard etc) and considering the construction of the rest of the house is almost certainly 100mm concrete block. 7x4 sounds a good idea... except that the piers (if needed) will end up being wider and eating into worktop space.

I think I'll probably end up building a pier at one end (probably the external wall end) just to make installation easier - rather than needing to knock a hole right through the external wall in order to manoeuvre the beam into place.

 

[Static]

For costing there is only going to be a few £s difference, and a 7x4 or 8x4 will do, and I would suggest will look better than a fat 6" beam, and would be about £100

The above would only work if there was no wall over the one being removed.. or the upper floor spans parrallel to the wall..

 

[^woody^]

I think I'll probably end up building a pier at one end (probably the external wall end) just to make installation easier - rather than needing to knock a hole right through the external wall in order to manoeuvre the beam into place.

A pier wont make installation easier unless the pier is about 200mm into the room and the beam cut about 100mm less than the width of the room.
Basically you still need to jig the steel about as it goes up on a slight angle, and it will be tight

And you don't need a hole right through the wall either

Knock your hole the width of the beam into the external leaf and make it about 150mm deeper than the beam - this would be the padstone or engineers depth, but don't put this in before the steel. Slide the steel up and in, and prop it in place and then put the padstone in after