Steel beam installation under first floor joists. Sloping Floor.

[Phillymclee]

Hi there. I am removing a loadbearing wall which is currently supporting the first floor joists at roughly 1/3 span. For context there is no wall above and the joists are continuous over the wall I am removing. I have had the calcs done by a Structural Engineer, notified building control and have already procured the steel. I will be installing a 178UB in place of the current wall with padstones at each end and was planning on positioning the top flange tight up against the underside of the joists and fixing a timber underneath the top flange and use truss clips to restrain each joist rather than having a timber plate on top of the beam to minimise the downstand. I thought that this would all be pretty straight forward but when doing some last checks the other night with a laser level I noticed that the current wall plate slopes from one end to the other by about 25mm (over about 3.9m) where it looks like the almost 100 year old house has settled over the years. So my question is whether I should install the beam level and pack the underside of the joists where required or install the beam following the slope of the existing wall plate then packing out the underside so at least the plasterboard is visually level. It seems a bit of a bodge to install a new beam not level but then it would be a lot easier to install it slightly sloped especially as all of the current brick coursing is also sloped so will avoid me having to slice a bit off the top of the bricks to one side when installing the padstones. But just wanted to check what the consensus was here to make sure there isn't something I have not thought of. Thanks in advance.

[ProDave]

My only thought is if there is no wall above, and the existing supporting wall is at 1/3 span, why not install the new beam at 1/2 span, i.e. not exactly where the existing wall is.  That would be better from an engineering point of view and you could install the new beam first, then take down the wall without jacking anything up.

 

1930's houses were not well known for having properly sized beams, one I previously owned had sagged upper floors and a brick upstairs wall not directly above the downstairs wall.

[Iceverge]

Great idea @ProDave. 

 

Personally I would be aiming for level or close to level with the new beam if I could without hurting the old structure too much. 

[Phillymclee]

Hi guys, thanks for the replies. I agree that would be better structurally ProDave and make the job a lot easier however to give you a bit more context I want the downstand to line through with the current wall return in the dining room and not in the middle of the room as that part of the wall will remain. Also I will be removing the beam supporting the stair quarter landing and replacing with a cranked PFC connecting into the new beam so don't want the span to be to big for that. And finally the steel has already been designed and procured for the current spans so I am stuck with what I have. Please see images below for a better idea of what I mean. Ignore the messy kitchen cabinets I'm still working on all of that haha.

 

 

Edited October 11 by Phillymclee

[Russell griffiths]

I think it’s hard to answer this without being in the room. 
I would get your props in place, get the steel in position, knock the old wall out, cut out for padstones, lift up steel, put jacks under steel  and wind up tight, then have a good look. 
does it fit tight to all the joists, can you even out the level by bumping up one end 5mm. 
have a play I think you will get a better feel for it when the steel is in position.