Correct RSJ - 1930s house

[shmelv]

im currently in the process of rennovating a house - possibly including knocking through a wall between what is currently a small kitchen and the dining room.

its a 1930s 3 bed semi so im sure many of you know the layout and have seen this work done plenty of times!

the Length of the steel will be 4metres and will be 100mm wide replacing what is currently a single brick internal wall, what would be the correct depth of steel for this work. Im trying t make two 'plans' one will include a knock through one will not. thanks

 

[Doggit]

It's not as simple as that I'm afraid. I couldn't do the calculations, but I can say that a structural engineer would ask you what type of wall is being supported what is the construction of the wall that the RSJ will be sitting on, and can they take the loading.

 

[tony1851]

Why is the depth of the steel beam important for your plans?
You design the layout you want, and the beam comes secondary.

 

[^woody^]

I suspect that a 305x102x33 would suffice

 

[Doggit]

So you're in a wind up mood this morning Woody

 

[^woody^]

 

[tony1851]

203 x 102 UB or 152 x 152 x 30 UC.

 

[^woody^]

Not a 178 x102 then?

 

[pilsbury]

What is the beam supporting? A few joists or the main wall in the house?

 

[shmelv]

254 x 102
203 x 102
UB
a
are the two sizes i have been advised ... this is strange, i have been advise the 203 but i asked a neighbour who has knocked walls left right and centre in a pretty much identical house and he has the plans and receipt etc from a veru similar knock through and had a 254x102 beam listed, im assuming he has been extra cautious, a good friend that is a builder advises 203x102

 

[Doggit]

Now are you doing this under building control, as they'll want the calculations done. Your neighbours may, and I reitterate the may do, or they may look at it, and give you a size that suits them, and saves you the calculations.

 

[shmelv]

thanks for the reply doggit, im not sure i fully understand your reply, sorry maybe i am reading wrong, yes work will be under BC .

 

[Doggit]

There are lot of people that just get on with the job, ignore building control, and then wonder why the solicitors ask for Building control completeion certificates when they try and sell.

The BCO will ask for calculations to prove the size of the RSJ, or if they're experienced enough, just tell you what size beam they want. But the calculations may get away with a smaller size, and it's then a question of which is cheaper, the calculations and a smaller beam, or no calcs, and a bigger beam.

 

[shmelv]

thank you for your explanation, from your experience do the sizes stated sound in the correct region i should be looking at. obviously the difference being one is stronger than the other but more expensive, although not massively.

 

[^woody^]

obviously the difference being one is stronger than the other but more expensive

Not quite. The issue is that one might be suitable and the other not suitable. You need this to be designed not guessed at by someone who used the same size beam on their last job.

There are several factors that could mean that whay seems like a suitable beam, would in fact not be suitable in a specific situation