Can you plaster/skim directly to steel?

[tonygreen1966]

Hi,
I hope someone can help me.
I am doing a loft conversion and need to run some steel posts down through my existing 100mm (including 12.5mm plaster board each side) partition walls. Problem is my steel posts are also 100mm. Can a good plaster skim onto steel? Would he be able to blend it over the rest of the wall with a complete skim?
I will meet Building Regs on fire protection by applying an intumescent paint with a special top coat the keeps the moisture from the plaster away from the intumescent paint.

Any help greatly appreciated.

Tony

 

[mattylad]

I'm no plasterer etc, but AFAIK there is a PVA solution that has little beads in that enables you to plaster over all sorts, this might be what you need ?

 

[roughcaster]

I've never plastered over steel posts before, so I can't comment. Be careful though using plaster over metal. Unless it's stainless or quality galvanised,,, gypsum plasters can cause rusting. Apart from that,,???

Roughcaster.

 

[Peadee]

Never done steel either but, I think Mattylad might be onto something there. If you can't find the product you could always throw a couple of handfuls of sand into your PVA. Thats what we plasterers have always done! Let me know if you find any of that beaded stuff, sounds great!

 

[jbonding]

It is possible and the stuff is either bond-it or betakontact, remember steel is similar to wood and will expand in certain weather conditions so expect cracking, its not something i would advise to do but if you fancy doing it, away you go.

 

[Richard C]

You can probably get plaster will stick to the steel with suitable prep but aside from possible corrosion problems already mentioned, it will always have a different expansion/contraction rate to the surrounding wall boards. This means it will almost certainly crack along the joins & continue to do so no matter what you do with it. You could try completely covering the steel beam with a woven reinforcing mesh (similar to jointing tape) out around 3-4 inches each side over the boards but that’s just my thoughts! Given the fire protection requirements as well, personally, I’d re-board the whole lot & skim that; PB isn’t that expensive & you will need to get it re-skimmed anyway so the additional cost won’t be that much & you’ll have a perfect job for years to come.

 

[roy c]

If you've got a steel girder or any steel that needs plastering over then it is best to stick plasterboard on it with "Sticks like Sh#t" or any other good "grab" adhesive. Then put your skim -beads on as normal and skim away....Sorry just re-read your post, so why don't you double board it and go over the steel with the second board?

 

[Richard C]

If you've got a steel girder or any steel that needs plastering over then it is best to stick plasterboard on it with "Sticks like Sh#t" or any other good "grab" adhesive. Then put your skim -beads on as normal and skim away....Sorry just re-read your post, so why don't you double board it and go over the steel with the second board?

Nice one Roy

 

[mattylad]

The PVA stuff I was on about, I was told that its something like £40+ a tub.

So double plasterboarding may be a better option.