what size "I" beam for 2.7Mtr opening?

[nottsrob184]

Hi all.
Can anyone tell me what size Steel beam (I beam) do i need to bridge an opening of 2.7Mtrs.
Basically, i want to open up an existing opening to a bigger width (2.7Mtrs).
I have just had a builder quote me £800 to prop up the brick and block work and remove the existing concrete lintel and install a new lintel.

I thought it was a bit steep so plan to do it myself.
Above the opening is brick and block up to second floor level and the cavity is 50mm.
Thanks

 

[hotrod]

Above the opening is brick and block up to second floor level and the cavity is 50mm.
Thanks

So this is a double skin wall with a 50mm cavity that you want to support Rob is that correct? If so you may need 2* 178*102*19 UBs possibly.

BTW that £800 doesn't sound too steep if it includes your BRegs fees and SE calcs (he will confirm your steel sizes) as that will weigh in at min £300, so that leaves £500 for labour and materials. Say £200 easy for materials - leaves £150 each for 2 men for a day. Don't go far does it?

 

[noseall]

I have just had a builder quote me £800 to prop up the brick and block work and remove the existing concrete lintel and install a new lintel. I thought it was a bit steep so plan to do it myself.
.

Steep my ar$e!
Do it yourself is what i say and good luck to you.

 

[andysuter]

isnt the main question "whats above the beam"? tell us whats holding up.

Is it near the corner of a building? or in the middle of wall? wind loads may be affected. Its not simply a case of knocking a hole in and stcking a big beam in.

Also... structural works need building regs

 

[nottsrob184]

isnt the main question "whats above the beam"? tell us whats holding up.

Is it near the corner of a building? or in the middle of wall? wind loads may be affected. Its not simply a case of knocking a hole in and stcking a big beam in.

Also... structural works need building regs

There is nothing being held up internally, (joists etc as they run parrellel to the walls).
It is near a corner but 700mm away. so its just outer brick and inner block.

Thanks to all so far.

 

[andysuter]

its got to be holding something up as i dont think its just fresh air above it?

You may be able to use a lintol, rather than a beam but it depends what situation its in

 

[RonnyRaygun]

If you've got brick outer leaf and block inner leaf, no floors and no windows, then Hotrod is right, a pair of 178x102s will be sufficient.
In fact, using the guidance in BS5977 you could probably get away with a pair of 152x89s, or possibly SHS or RHS.

However, you still need to be able to show BC the calcs that prove it, so you're going to have to pay an engineer to do them for you.

Will the steel carry any of the new roof load?

 

[andysuter]

if thats the case a catnic cg 90/100 lintol will do it off the shelf! no need for calcs.

 

[RonnyRaygun]

if thats the case a catnic cg 90/100 lintol will do it off the shelf! no need for calcs.

True, I guess, although I've got a feeling BC would want to see some proof that a CG90/100 was sufficient, as a first impression would be that something much sturdier would be required

 

[andysuter]

but its an existing opening, most likely with an existing lintol over it, which is being made wider to 2.7m.

Surely its a simple case of removing the old lintol, propping and making opening new size and insert new lintol. Ta da!

Catnic (or most other manufacturers) do lintols up to 4.8m long! with all structural calcs self certified.

Cant see the point in installing two seperate beams to do the job of a lintol, espcially when you then have to insulate and box them in.

 

[RonnyRaygun]

I agree, but chances are your friendly building inspector won't be familiar with BS 5977 - as won't the average DIYer - and might not be satisfied that it's only carrying the load it's carrying without some proof.