12mm crack in room above new RSJ

[^woody^]

LOL ... here we go again Tony!

Tony and I had this debate previously and my take on it is that whilst beams may deflect under load, the whole point of the deflection check calculation, is to ensure that the beam does not deflect to such an extent, so that finishes crack ... let alone the actual wall moving

I'd certainly not agree with that BCO in that he "allows" deflection of 15mm ... that is 15mm of cracked plaster, 15mm of dropped skirtings, 15mm of creaky floors, 15mm of jammed shut windows, 15mm of leaking joints around windows etc. Complete nonsense.

IMO that beam is either undersized - as it is deflecting too much, or its not been put in properly

Either way cracking above this beam is not satisfactory

 

[RonnyRaygun]

I design for span/360 maximum (dead and imposed) where a beam carries existing masonry, less if the span is long or there are openings above.

It seems to me that building control all too often turn a blind eye to obvious defects and cutting of corners.

Some questions:
1. What size is the beam?
2. Is it well packed with mortar between top of beam and underside of masonry?
3. Are there pad stones? If so, are they well bedded on mortar.
4. Was the mortar set before acros were removed?

Someone has made a mistake here, be it the designer or the builder.
Your house is not about to fall down, and the cracks hopefully won't get any worse, but the BRE recommends toothing in new brickwork when cracks exceed 10mm.

 

[tony1851]

Get the builder back to put it right.

What if it's not the builder's fault, though?

 

[Static]

LOL ... here we go again Tony!

Tony and I had this debate previously and my take on it is that whilst beams may deflect under load, the whole point of the deflection check calculation, is to ensure that the beam does not deflect to such an extent, so that finishes crack ... let alone the actual wall moving

I'd certainly not agree with that BCO in that he "allows" deflection of 15mm ... that is 15mm of cracked plaster, 15mm of dropped skirtings, 15mm of creaky floors, 15mm of jammed shut windows, 15mm of leaking joints around windows etc. Complete nonsense.

IMO that beam is either undersized - as it is deflecting too much, or its not been put in properly

Either way cracking above this beam is not satisfactory

Agreed.. deflection design should suit the purpose of the building not just the code..