open string staircase

[jim]

Anyone made one?

Seems that to buy they are frighteningly more expensive than "ordinary" closed string staircases - why?

Any pointers gratefully received

Jim

[John Rumm]

I have made a closed string, open can be harder or easier - much depends on how ornate you want the result to be.

The extra detailing that can be done will take more time to do - so that would also contribute to the cost. You will need more substantial timbers for the strings. Treads cut form wider boards to allow a return around the edge of the string, and the edge of the riser and the part of the string it meets often need to be mitred to make a neat joint.

They are also less commonly used in this country, so less demand perhaps. Common in the US though.

What do you want to know?

(a quick google search will bring up lots of photos etc)

There is also a book available: Building Stairs (For Pros, by Pros)

[jim]

how to make one!

seem to mention open strings - do you have the book and does it?

cheers Jim

[John Rumm]

What sort of stair - straight run, winders, quarter landings etc? Hardwoood or softwood, on display or mostly hidden?

Will it be open both sides, or fitted against a wall? (where it is common to have closed string against the wall, and cut string on the visible side).

Construction of either follows a similar path. Cut the strings first - with open ones this is really just a case of cutting a staircase pattern out of the top of the string, Then route out any tread recesses in newels if you have turns. Then make the treads and risers.

A common trick to make the riser to string joint look nicer is to mitre the ends, however rather than do this on the string itself, you can use a decorative infill that sits under each step and is planted on the outside of the string. I can draw it for you if you want.

Its a Taunton book (same US company that does Fine Woodworking magazine), and the pictures shown on the contents page show a number of open string stairs - so I would expect it is almost certain that it covers them - quite possibly in more detail that closed string.

[meow2222]

Could hardly be simpler.

1. Work out the max human weight its possible to fit on the staircase
2. Size the strings to support this with acceptable deflection, allowing some margin and checking they can support 3x that weight (deflection regardless)
3. Do the same exercise to find the minimum size for each tread, then choose what size you want
4. Each tread is then just a rectangle sitting on a triangle at each side sitting on the strings
5. Ensure the wooden triangles each have at least 2 fixings to the strings. Job done.

NT

[John Rumm]

Its often easier to just cut the staircase pattern (i.e. the missing triangles) out of the top of the string so that you are left with solid strings and no bits to fix on.

[jim]

2 straight runs, 6 and 7 rises respec, half landing between, softwood would be OK (painted), not *bling* just simple and classic.

Definitely don't want newels - rather a nice volute at the bottom & a continuous handrail all the way up - Richard Burbidge has most components for this - does anyone else offer these sorts of turnings etc??

yup one string of each against a wall, other open string on inner of each flight to make a nice 5 or 6" gap between strings to gaze down (and let light in)

Can you advise what size timbers I should be looking at for softwood? are there regs on construction (apart form going, rise, angle, banister)??

if you can I would be obliged (or a link to a pic)

I wonder do our american relatives use a dfferent word/phrase for "open string"

is there a UK equivalent? (to sidestep any more potential phraseological pitfalls?!!)

cheers Jim

[sm_jamieson]

I've often seen these (US movies !) and it looks like after the strings are cut out, there is very little left to support the stairs, e.g. 1 foot high strings seems common for stairs here, that would leave about 3" from the examples I'm seen. I've not investigated this in any detail thought ! SImon.

[sm_jamieson]

Usually called a "cut string". Simon.

[meow2222]

Certainly saves cuttting and fixing the triangular pieces. OTOH it means using more massive strings, since you're cutting into them a fair bit. 4-6" timber is good with the triangle method.

The other - and bigger - consideration is that when cutting triangles, any mistakes go in the bin, whereas when cutting for the treads to go into the strings, one mistake and you're stuffed. Both work, but for someone not experienced and confident I'd go with the triangular bits myself. I also prefer the appearance.

NT

[John Rumm]

Not that I am aware of. I would select a timber for the string that will leave 4 - 5 inches at the narrowest section, and perhaps 2" wide for the cut end.

Rough attempt here - will tart it up later:

I wonder do our american relatives use a dfferent word/phrase for > "open string"

yup, cut string.

[jim]

(google sketchup I presume? I'm a fan of it myself) Off to the timber yard next to find some suitable sections - I'll definitely have a go & make a short flight to start

cheers Jim

[John Rumm]

Yup! ;-)

There are plenty of ways you can fiddle with the design. You could skip the decore blocks and let the riser sail past the string as well, that would save needing the return on the treads. With a rounded over end on the riser and some moulding tucked up against the back of it where it overhangs the riser on the string it could look effective as well.

[meow2222]

I've done a diagram of the other type I mentioned, a simpler construction. Its here:

the formal name of this type?

NT

[John Rumm]

Open riser, with cut (or open) string. Often used on decking and garden steps - not so popular inside these days (would not pass building regs without at least a bar in the centre of the riser position to stop your foot slipping through)

[Hugo Nebula]

On Thu, 07 Aug 2008 01:45:40 +0100, a particular chimpanzee, John Rumm randomly hit the keyboard and produced:

The bar is or would be there to stop a child falling through or being trapped. The requirement is that a 100mm diameter sphere cannot pass through any gap. It only applies to buildings where children under five could be present, so it applies to dwellings and public places, but not offices, etc.

[dennis]

Open days?

[jim]

responsible parenting?