Welding stairs in situ?

[stoaty]

Hello

Our house has a steel framed, spiral (well, helical actually) staircase. At four or five points (generally underneath the treads, which can be removed) the frame has snapped.

My question is .... is this the sort of thing it is generally possible to weld 'in place', or does it sound as if the stairs will have to be dismantled, taken somewhere off-site, welded, then reinstalled?

The wooden stairs can be removed easily enough, leaving just the frame, but the stairs are in the corner of the room, which is why I'm suspecting the welding will have to take place elsewhere.

Any ideas?

[EricP]

I would be more worried as to why it snapped. It is obviously bearing a greater load than it is made for/badly made.

I would consult the manufacturer and get their comments and replacements from them

If welding is required this should be fine in situ but certainly strengthening should also be undertaken.

[stoaty]

I suspect it is from previous owners (stairs were installed by Barratts when the house was built in 87) over tightening the stairs.

[Cicero]

================ Are you sure the broken pieces are steel? They may be cast iron in which case they will probably need to be removed for repair. If they really are steel then repair 'in situ' should be straightforward provided that you can protect the surrounding area from damage such as 'spatter' etc.

Cic.

[EricP]

Sounds like cast iron.

Might be useful to put a few pictures up on a web site and let people here look at it.

You might find it useful to ask a small local steel fabricator to have a look at the problem. You don't have to buy them, but comments they make, might be useful. :))

[Andy Dingley]

What has "snapped" ? A pre-existing weld, some steel, or some cast iron.

I'd expect any steelwork to be weldable in situ.

Steel shouldn't snap. So either the steel failed, suggesting a design fault, or the weld failed, suggesting either a design fault, or a technique fault. Either is weldable, but you'll need to fix any design faults as well. This may involve adding some welded-in buttress or splice plate.

If it's cast iron, I'd not even try to weld it. CI is a pig to weld at the best of times, the grade used here doesn't help, and it's an uncertain strength afterwards. You'll need to remove it from the stair to work on it, so on-site / sent away isn't all that different in the end.

If it's cast iron and irreplaceable, then I'd use a steel patch alongside it. This is a difficult thing to design, because you need to avoid further breaks where you attach the repair splice.

Alternatively throw away the cast iron one and make new brackets from steel. With a plasma cutter (or waterjet, for bulk production) you can reproduce an awful lor of simple iron casting in profiled steel, welded together as a built-up construction.

[Kaiser]

If the stairs are steel they can be repaired in situ, best done with an arc welder using high carbon rods for strength. You will need some fire blankets to protect the surrounding area.

If they are cast iron they will need to be removed, taken to specialist welding firm and pre-heated before they are welded, or the stress of the weld shrinking on cooling may cause further fractures.

[Mike]

Depending on construction materials used, they may not even be weldable at all.