Plastering on steel lintel

Gary_zero

Hi I need to plaster the underside of a steel catnic lintel that spans 1500mm over french doors whats the best method - Thanks

lagi

Best method is to cut some plasterboard and stick it/fix it to underside, then you can skim it. Common method with reveals and cavity closers also.

keystone

Overboard and skim. Even if you can get your plaster to stick properly differential expansion/contraction rates will mean it cracks off in no time anyway.

Cheers

trumpton

As above. We have several steel rsj's in our extension - they have been plasterboarded over reading for skimming. In a large joist, you can screw wooden blocks into the steel and then screw the plasterboard into that to provide support over a long stretch.

Gary_zero

Whats a good adhesive to use? No more nails or what?

lagi

Maybe a gripfill, but you could use plaster adhesive like for dot and dabbing.

Radsteral

catnic litels, normally have lots of holes on the underside.
You can get a bag of lasterboard addisive or bonding compound as they call it...wickes sells them , b and dont.
cut the plasterboard on reuired size then miz some of the above stuff and dot it on the lintel, making sure it penetrates on these holes of the lintel.
stick the plasterboard in and you need a piece of wood .. if plasterboard is 150 cm long, you need a wood 140 cm to put underneath it , and then another piece of woof vertically to push up.

DVardysShadow

Radsteral wrote: »

... and then another piece of woof vertically to push up.

is that wood with the bark left on?