Steel Beam Instalation

[mirovyaneto]

Hi, we'll be installing three steel beams for loft conversion soon & I have few questions to ensure we follow the best practice:
1) Corrosion protection
We're planning to have the steel (S355) painted with zinc primer - is that sufficient?
2) Fasteners (for spliced beam)
What type will be best to reduce the risk of galvanic corrosion - stainless steel, plain finish carbon steel or galvanised?
Also what method is used to prevent loosening of the nut? I guess the risk is minimal as there's no relative movement, but still should play it safe.
3) Gap to outer leaf of cavity wall

Beam

• mirovyaneto
• 8 Apr 2017

One end of the beam is in a cavity wall - what gap is normally left to the outer leaf?

Thank you for your help

 

[John D v2.0]

1 and 2 are questions for your SE, and 3 you need to keep it flush with the outside of the pad stone and make sure the insulation covers the outside completely.

 

[tony1851]

1. You do not need corrosion protection for steel beams in a loft conversion.
2. If you are having a proper splice made (and not just a welded end-plate affair) the bolts will be grade 8.8 friction-grip bolts
and your SE will (or should have) specified the size and spacing of the bolts, and thickness of connecting plates.
3. it is immaterial what gap you leave between the end of the beam and the outer skin. What matters is that the beam has
the full 100 bearing on the padstone on the inner skin.

 

[mirovyaneto]

Thanks for the replies - it's very helpful.
The bolts are specified as grade 8.8 - I guess we can use load indicating washers

 

[tony1851]

Thanks for the replies - it's very helpful.
The bolts are specified as grade 8.8 - I guess we can use load indicating washers

Either load-indicating washers or a torque wrench but washers are easier.