I recently put up a couple of standard 2m fence panels; they stand at
the edge of a reasonably substantial drop though, so it's really
important they don't get pushed over (TBH I think I now regret not
having erected steel railings instead).
I've decided that it wouldn't be a bad idea to attach a length of mild
steel to the reverse (hidden) side of the fence, just below the top; ie
screw a 4m length to the three fence posts, so it would act as a rail
and prevent the fence panel from breaking and falling over the edge if
someone fell really heavily against it.
Question - what would be best to use: angle iron or solid steel bar of
comparable substance/cost - eg, say 20x20x3mm angle iron vs 12mm solid
bar? (I favour the angle iron in the sense it will be easier to get
through with my hand drill!)
Also - where, as a civilian, am I best going to buy this sort of stuff?
I don't normally 'do' metal; the last time I bought some steel years
ago I went to a local steel stockholder and got royally ripped off I
Probably more effective to put up a post and horizontal rail fence
inside the panel fence, so that if anybody falls, they hit the rail and
not the panel. Following health and safety guidelines for workplaces,
such a rail should be 1.1m high and there should be a second rail at
half that height.
You could do that in wood if you prefer to work in that material, but do
make it substantial enough to take a heavy falling person. 3 inch / 75mm
is probably the minimum size of timber to use and the posts need to be
really solidly mounted.
If you prefer the steel idea, I don't see the point of putting it at the
top, away from the probable impact zone. It would not stop somebody
breaking through a light fence panel there. It should be mounted where
the person is likely to fall against the fence, i.e. the same as the
post and rail fence rails.
Angle iron will have greater stiffness.
If you need a 4m length (or two) then a steel stockholder is probably
your only choice. You will likely find it cheaper to buy a 6m length and
cut it yourself than to pay a cutting fee and get a 4m length.
I've found www.metalsupermarkets.com not too bad. Although their
asking prices are a little high, you can often haggle a bit with the
At least they have a good range of stuff in stock at their various
[No connection with this organisation.]
Buying from industrial suppliers, steel section will usually be supplied
in 6m or longer lengths. An alternative for this application, if rather
heaver section is used, could be aluminium, which normally comes in 4m
or 5m lengths.
As said, angle iron better than solid. You don't need to go the full
height; posts tend to break at the base as that's the weak point with
the rest of it acting as a lever. Anyway, it only really works if
someone throws themselves at the post; panels tend to be so flimsy I'd
expect a Tom and Jerry style person-shaped-hole if someone fell against
it while the unreinforced post wouldn't be unduly worried.
Google for Metal Supermarkets. Dealt with them when I had one close and
their pricing was pro-rata for small bits.
Alternatively, an idea having just hit, how about steel wire running
from end to end behind the panels (since there's a drop, I assume
there's no one the other side to moan about aesthetics) in the same vein
as motorway fencing? Attach to each post at similar positions to Colin's
rails and a) the force is distributed among all of the posts and b)
they'll stop someone going through the panel. Be a lot cheaper than a
full handrail (S'fix do it in various sizes and 25m lengths for buttons)
 ie drunken party go-er.
On Thu, 27 Jun 2013 08:16:13 +0100, Lobster wrote:
Over 2 m both will bend when pushed in the middle but the angle iron
less so. TBH gut feeling says that 20 x 3 angle ona 2 m span will
just buckle if a decent sized person fell heavyly onto it. I think 40
x 5 angle or something of that order would be more suitable and
mounted at the height suggested by Mr Bignell. A stong member at 6'
isn't going to catch someone crashing straight through the fence
Post and rail stock (horses, cattle...) fencing uses roughly 4 x 2
timber rails at 6' post spacing. Couple of those may well be cheaper
and easier to handle/fit than hefty lumps of steel.
Not necessarily a bad thing, providing the fixings hold and the person
does not fall right through. A rigid rail would have advantages if
people are expected to use it regularly, but for something that is only
supposed to guard against an unlikely accident, some give might soften
the landing a bit.
The suggestion of series of tensioned wires is a good idea and, if put
on the inside of the fence, they could be used to train plants as well
as providing security.
20 x 20 is a bit floppy, you may want something a bit heavier and/or use
square hollow tubing instead which is more rigid.
Lot's of steel stock pricing is driven by the weight of the steel in it
unless the complexity of the manufacture adds significantly to that
cost. That should make angle the cheapest option with RHS a bit more I
If you have a branch nearby, I can recommend Metalsupermarkets,
reasonable pricing and no minimum order.
Their site used to be an absolute shocker but I see it has been improved
and the even claim online ordering but the delivery would probably be
Even if you're not close, you could get a price over the phone from them
and then tout it around local steel stockholders in your area. With
those however you may come up against a minimum order charge.
I agree with Colin's suggestion that the bar should be at handrail
height but I'm guessing that you might have access difficulties getting
to the back of the fence over the dropoff<?>.
Given that, you may want to change direction a bit and add a straining
wire to the front of the fence at handrail height instead. I've used 6mm
braided galvanised steel wire in tensioned fencing, it's very strong and
looks nicer than plain fence wire. You could drill the posts and thread
through to firmly link it to the structure. I thought you might end up
pulling the end posts in a bit when you tension it (with straining
screws) but as you have panels in the gaps it should just squish them up
a bit. The benefit of this system is that the parts are cheap and light
so easy to mail order - ah, also avail from toolstation:
If you do use angle iron, consider fixing it so that its surfaces are at
45 degrees to horizontal - e.g. drill through the 90-degree bend and
screw to the fence/posts like that. Advantage is that it will drain well
and be less prone to rusting through in short order.
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