Repairing a rusty steel-framed barn

[BluntChisel]

My relatives have a steel-framed barn, and some of the steel frames are seriously rusted where they meet the ground (please see first picture). I don't know the state of the steel higher up, but it's rusty on the outside.

The barn is about 20m long, 7m wide, and 4m high at the ridge. It is constructed from 6 steel frames, linked by heavy timbers. 4 of the frames have 4 "legs", and presumably exert little lateral force on the ground. 2 of the frames have only 2 legs, and presumably exert outwards forces where they meet the ground. I'm more concerned about the 2-leg frames. Despite the rust, there are no signs of imminent collapse.

I'm looking for ideas for repairing and strengthening the barn. I'm fairly comfortable with bolting big bits of timber together and mixing concrete. I'm considering replacing or complementing one of the rusty "2-leg" frames with an over-specified wooden "4-leg" frame. What sort of timber might be appropriate?

On the other hand, would this be a good excuse to buy some welding gear and learn how to weld? What sort of equipment, steel, and perhaps formal training would I need to replace a frame?

(the main problem) (shows a frame with "4 legs" in foreground) (ridge joint) (shows a "2-leg" frame)

Thanks.

[Peter Crosland]

I would suggest the owner gets urgent professional advice from a structural engineer before any work is attempted and before anyone else is even allowed in or near the building. The owner also needs to check their insurance covers them because the premises could easily considered defective. The possibilities for serious injury or even death by attempting an amateur bodge are high. It is clearly not a job for someone who clearly has no idea of what they are doing and what might be involved.

Peter Crosland

[John Williamson]

And in the meantime, pray that there are no high winds. If all the leg bases are as corroded as the one you took a picture of, there's very little strength left.

[Tim Lamb]

In message , Peter Crosland writes

Hear, hear!

Wait for Tony Sayer:-)

I guess that barn pre-dates BS5502 agricultural barns by some distance.

Several obvious criticisms; the ridge joint needs strengthening, there are no apparent wind braces and the steel used looks too light for the roof pitch. At least it is clad in lightweight steel and not asbestos cement.

There are issues with DIY welding for structural steelwork, particularly if the building has any commercial use (used by employees or let out etc.) I don't know the details but I think you need some form of certification. You could probably find someone with a mobile welding set and the right certificates.

An easy way round the ridge issue would be to fit tie beams at eaves level. Connecting these to the uprights is problematic as you don't want to drill holes. Some sort of collar perhaps.

Repairing the rusted upright looks straightforward. In the absence of strong winds, the only load should be vertically downwards. This can temporarily be carried by Acro props. Breaking out the foundation pad might find sound steel. Modern box section steel comes in nesting sizes but I don't know if you will find a tight fitting sleeve for what is there. Two pieces of angle iron might be arranged to fit over the existing but, as Peter says, this whole job requires professional advice.

regards

[Andy Dingley]

Well that's well knackered, isn't it?

Did something similar for the neighbours a few years back. The basic method was to Acro under the frames to take the weight off each leg, then saw each leg off about 3' above ground level. The old leg and (too small) concrete base was broken / lifted out, then a new leg set in place in new concrete and welded. The joints were (AFAIR) a butt weld in this 6" H girder and then narrow flat strap plates welded over the outside of the webs.

Biggest pain was the need to repeat this eight times, rather than being able to do all the digging, then all the lifting in one go, with a fair wait between each step for concrete to cure. Even with a tractor and front bucket on hand for lifting, it was a right nuisance to get the old bases out. The steelwork was pretty easy in comparison.

Dad's barn (a Wareings kit) uses 12" girder, but then he over- engineered stuff even more than I do.

[fred]

A structural engineer told me years ago that the strongest thing about a hay barn was the steel roof. And he wasn't joking. I've actually seen a late 19th century/early 20th century barn where the only structural steel was the legs and a tie bar between them with a vertical round bar running up from the centre of this tie bar to the ridge of the round roof. And it was still in use 20 years ago when I saw it.

Do nissen huts (quonset to any visiting merkins) have much structural steel in them. ISTR seeing them as just a curved roof ( to the ground) structures with the corrugated panels just bolted together.

I'd follow the suggestions to use acro props and re-inforce each leg where necessary. You might want to check the condition of the 7" x 4" timber purlins though they were generally pressure treated.

Paul Mc Cann

[Andy Dingley]

Depends on the barn design. Some (if they have wall plates, even if they don't have walls) can be lifted by a crane without trouble, because it's a rigid steel rectangle, diagonalised by its wind braces. OTOH, most barns, including the one here, are a set of portal frames, so there's a risk of it collapsing like dominoes towards one end, unless there's something else to stop it. I think Dutch barns tend to have a strong roof as a unit, because there are no sidewalls to assist, but it isn't generally the case.

With this building repair here, I'd probably also diagonalise the side walls (Xs of light tension rods, with turnbuckles) to stop the risk of dominoes. I wouldn't trust those wooden purlins (or at least, not the connection to them) to do it.

They're _entirely_ structural steel. That outer skin is the structure, that's why they have to be curved.

[Grimly Curmudgeon]

Nissen huts have an internal frame, but Miracle Span buildings are simple deep corrugated curved steel panels which bolt together to form a series of arches which are then lifted to overlap. Something like these, but the earlier ones were more of an arch; now they have more squared sides.

dealt with them decades ago and was mightily impressed at how quick and easily they could be erected - many of the smaller buildings were put up by two blokes.

[BluntChisel]

Thanks for all the replies. To answer some questions; the barn is about 30 years old, and was built by someone with more farming than building experience. The photos show the worst bits, the rest isn't quite as bad. There's no asbestos. The wooden beams appear to be in better condition than the steel frames. It's used for storage of cars, and most of the time contains only swifts and rats.With suitable repairs, I think the barn has some life left in it yet.

I will advise my relatives to be careful, and suggest they seek professional advise sooner rather than later.

However, I suspect they would prefer a DIY approach, for various reasons. I now realise this isn't an oportunity to learn to weld, but I'd like to consider supplementing the existing steel frames with timber frames strong enough to completely replace them eventually. We have woodworking experience, but nothing on this scale. Can anyone suggest a book that would describe how to design and build such a frame, eg. sizing of timber, calculation of forces, safety margins, fixings, joints, foundations, etc ?

[Grimly Curmudgeon]

Of course it is. Simply sign up for a welding night class and go at it. Many thousands of farmers never formally learned to weld (although, it could be said it might have been better if they did) and happily repair gates and buildings. Happy in their ignorance, perhaps, but a load of pigeon-shit weld is better than none at all. I'm being unfair to farmers; plenty of them can weld quite well, actually. :)

Back to your building; it's been said already, acro props and digging up the old post bases, then fitting new and welding to the old is the way to go. If you're not sure of the strength, add more. Simples.

[Tim Lamb]

In message , Grimly Curmudgeon writes

Umm... Stick welding (3.2mm rod) those uprights would need upwards of

120 amps. I don't think you would get that from a hobby welding set fed from a 13 amp socket.

[Peter Crosland]

I really don't think you have got the message. Just entering, or working on, a building that is in such poor condition could trigger an unexpected and catastrophic collapse. That could easily result in the serious injury or death. That might well result in the owners being prosecuted quite apart from the personal trauma it would cause. You really would be extremely foolish to have anything to do with it other than to warn your relatives of the peril.

Peter Crosland

[tony sayer]

In article , Tim Lamb scribeth thus

Umm ... what's my involvement in this Mr Lamb pray tell?...

[Tim Lamb]

In message , tony sayer writes

I had thought that you might point out the inadequacies of butt welded rectangular steel section used for portal frame construction:-)

The last steel frame barn I erected was supplied with 175mm x 102mm I beams and the ridge joint was reinforced with a full depth welded gusset. Admittedly this was a 30' span but not wildly dissimilar.

regards

>

[Andrew Mawson]

Peter

forces where

Despite the

welding gear

insurance

defective. The

By the time you have faffed arround patching it up it would be much simpler, and probably not much more expensive to replace it. I had similar problems to cope with here - there was a two bay barn with planning permission for a third bay, but the original two bays had been recycled from elsewhere and errected on a sloping concrete pad so the steelwork was not upright. I had to work with it as I couldn't afford the time to re-submit plans to demolish and replace, it was not at all certain it would be granted as we are in an 'area of outstanding beauty'. Cobling the new bay on was great fun, as was breaking out the floor to level it!!!!

BTW by the time I'd sandblasted the original steelwork it looked far better than initial impressions and needed less fixing than I'd thought. (The project was a good excuse to by a full size Hodge Clemco sandblaster )

AWEM

[fred]

The necessity for gussets in steel portal frames is dictated by the sections used in the legs and rafters. If legs and rafters are of a similar size and correctly calculated then gussets are not required. They are used to allow smaller/cheaper sections be used.

If this barn has at least one bay of wind bracing in the legs and roof, which it certainly should have, then the risk of a domino collapse is negligible, assuming its not completely gerry built. If the cladding and roofing is removed then there is no chance of a domino collapse. Most of the strength built into steel portal frames is to allow for 100 year snow/wind loads (I forget the exact number of years). Without roofing or cladding these loads will be minimal..

Paul Mc Cann

Paul Mc Cann

[Steve Walker]

Just had a glance at Machinemart and a basic hobby Clarke Arc welder is

185A. How long it can sustain that is prehaps another matter!

Steve Walker

[Tim Lamb]

Gathering dust under a workbench, I have an old air cooled transformer welder (the type where you alter the iron circuit to change the o/p voltage). That would regularly blow 13 amp fuses with 3.2mm rods.

regards

[Andy Dingley]

Bollocks. It will take at least a day's practice (and that would be a hard day) to become at all competent.

IMHO, you can learn to weld from a good theory textbook (it's short enough, but you do need it), some basic nous, no instructor at all (although they don't hurt, they aren't essential), some application and refusal to take shortcuts, and most importantly PRACTICE. If you haven't got a wheelbarrow or so of small sheet scrap and welded the lot into a solid lump (or similar volume of welding), then you haven't practiced enough. You also need to start sectioning, polishing and etching your welds while you're practicing, so as to understand what you're achieving.

As always, Gibson's "Practical Welding" is my favourite.

You also need to prepare the welds properly beforehand, and to understand the construction of a multi-pass weld. I'm concerned about descriptions of slipping tube sections inside each other, like some sort of Lego. You need to weld this, and weld it in the right place, not just slip it over - that way you can't get access where you need it.

It's a farm, I bet they have a decades-old oil-cooled Oxford already.

You need a grinder to prepare the cut steel anyway, so why take two bottles into the shower of sparks?

Besides which, this is a hay barn. It's hard enough to control grinder sparks, let alone oxy-acetylene.

[Tim Lamb]

In message , Andy Dingley writes

snip

I had concerns that in situ butt welding might not be practical for a beginner and that a sleeve would provide some lateral stability to what might be a weak portal arrangement. The bays with intermediate uprights look strong enough.

Quite. Following the thread on burst grinder discs, it is essential there is no compressive load on the leg to *grab* at breakthrough.

Job for an experienced professional.

regards