Segmental arch

[kes]

hello this is kes

can anyone tell me how to find the striking point of a segmental brickwork arch that is so close to the ground or so wide that the originating point is actually below ground, so i am unable to use a taught line to accurately lay the bricks to get consistent joints ???

[lutonlagerlout]

you normally do this on a sheet of ply on the deck then cut 2 mirror images from ply and fix them together at your required wall width
if you lay a sheet of ply on the street say you could go 30 M away to find your striking poiint
regards LLL



Edited By lutonlagerlout on 1225736850

[Tony McC]

By "striking point", does this mean the origin, ie, the point from which the arc is swung? I'm not overly familiar how the terms used by brickies compare to those used in the civils trade.

[seanandruby]

By "striking point", does this mean the origin, ie, the point from which the arc is swung? I'm not overly familiar how the terms used by brickies compare to those used in the civils trade.

http://www.diyinfo.org/images/a/a6/Brickarch_D.jpg
Tony i think this is a link to what you asked for.

[Tony McC]

Thanks Sean

Not so keen on those wide joints, though!

[kes]

THANKS FOR YOUR RESPONSES TO MY QUESTION ABOUT SEGMENTAL ARCHES, BUT I'M STILL UNABLE TO ACCURATELY LAY THE BRICKS SO THEY ARE RADIATING TRULY FROM THE STRIKING POINT AS IN SEANANDRUBY'S EXAMPLE OF A SEMI CIRCULAR ARCH, BECAUSE THE STRIKING POINT OF A SEGMENTAL ARCH IS LOWER BEING ONLY PART OF A BIGGER ARCH. I HAVE SET THE BRICKS OUT ON THE DECK LIKE LUTONLAGERLOUT SAID SO THE ARCH FITS CORRECTLY INTO THE OPENING BUT I STILL CAN T ACTUALLY USE THE STRIKING POINT TO PRECISELY RADIATE THE BRICKS AS THE STRIKING POINT ORIGINATES BELOW GROUND. AM I MISSING SOMETHING OBVIOUS HERE? ???

[flowjoe]

Kes M8

Do me a little favour STOP SHOUTING

I come here for the piece and quiet

[seanandruby]

Kes dont know if you realise that using caital letters is classed as shouting. now if brewers like floe' have an hangover it hurts
any chance of some photos, how far off the ground is the arch?
helfen do a lintel and rod system that may help you.

[danensis]

I've only ever done this once, and I curved a sheet of hardboard over the top of the centring, and then arranged the bricks on that, keeping the end of the brick flat on the hardboard (and therefore on a radius) and then packing the joints with mortar to keep the bricks at the right angle.

John

[danensis]

Thanks Sean

Not so keen on those wide joints, though!

The wide joints are unsightly, though in theory the bricks can touch at the inner end. The only alternative is to use rubbed voissoirs - but that's a lot of work if you rub them down yourself (there's a joke in there somewhere).

John

[lutonlagerlout]

when i was a lad the guy that taught me to lay bricks said when he did his time he spent weeks rubbing down voissoirs (pre grinder days dont forget) that is why a lot of arches are built in soft Leicester reds

i dont understand your problem kes?
if you have the width of the arch and the rise then it can all be drawn on a piece of paper using a ruler and compass,then scaled up and marked out on 2 sheets of play,that are then cut with a jig saw and fixed together at the required wall width

the arch former is then propped up (remember a 10 mm wedge so you can get the poxy thing out without knocking the arch down)
is this what you are trying to do?


cheers LLL



Edited By lutonlagerlout on 1226597228

[seanandruby]

.....best to use a couple of folding wedges, that is two wedges pushed towards each other for ease of striking

[kes]

this is kes again

lutonlagerlout, do you mean fix the ply template on top of the centering(ie back far enough so you can put bricks in front of it) and just lay them to the pattern already marked on the ply?

[lutonlagerlout]

no mate the play template goes under the arch,so if you have a 225 wide arch you would make your template at 200 mm say spacing the 2 arcs of play with 3 by 2 or such
you then build your bricks on top of this ,cutting where necessary and let it go off for 3-4 hours at least (a day is best) before striking the arch former
i get a chipie to knock me formers up he charges about £70

i did have about 20 in the garage but i ended up chucking them as they very rarely get used twice IME

cheers LLL

[Tomas]

Hi Kes

A handy way is to place the template on a flat surface and set out the bricks dry around the circumference of the arch.
Cut or adjust the bricks where necessary and then mark the joints on the template.

Only a matter of then setting ur template in position and build to the marks. I find this way is a lot handier and gives good results. Also no need to use a string from the striking point.

Tomas.