Max P/C Lintel Span

[ldoodle]

Hey,

Planning to open up a downstairs internal wall between kitchen/dining room. The opening will be about 1500mm so min. lintel would be 1800mm.

There is no wall directly above this wall (the wall upstairs is offset by about 7/800mm), but the joists above run over this wall (forgotten the word!), not parallel to it.

Are P/C lintels up to this task? http://www.wickes.co.uk/invt/220333

Thanks

 

[tony1851]

A 100x65 p/c conc. lintel won't do.
You would need a 140 deep p/c conc. lintel;
or a 152x89 steel beam;
or two 2"x8" timber beams nailed/screwed together.

 

[ldoodle]

Thanks; http://www.less2build.com/concrete-...tressed-txtured-concrete-lintel-100x140x1800?

Would you say that's the absolute minimum, or will it be more than enough? Just wondering if I should play safe and over compensate. Price is not that different.

PS: Crazy to think that my last house had a single 2x4 for the opening into the kitchen, supporting an external wall!

 

[tony1851]

Personally I don't like p/c lintels in breakthroughs as; 1. they are heavy and 2. some of them are 'composite' meaning that they are intended to be built in as work proceeds (ie primarily for new work)and they take some of their strength from the bond with the courses above. This obviously doesn't apply in a break through.
The fact that it's holding 'just' a floor (and some load from a partition) is not necessarily an advantage as these lintels are not good at taking shock loads.
But if my arm was twisted I'd have to say a 140mm would do - I suppose.
If that were my job, I'd get a couple of pieces of 2x8 timber from a local merchant and screw them together. You can notch them down at the ends to 6" or so to fit your courses, and it's easy to fix plasterboard to it. Easier and cheaper all round!