Railings on your wall

Your wall, not somebody else's

Take a photo of the wall, drop it in, and the railings go on top of it. Drag them where they go, scale them to the run, and try the styles.

Every other way of doing this is a gallery of other people's houses. That tells you what railings look like on a Victorian terrace in good light, which is not the question. The question is whether they look right on your wall, next to your brick, at your height, and the only photo that answers it is yours.

It is drawn to your dimensions, not sketched

Give it the length of the run and the height and it works out the posts, the bays and the bar spacing properly.

The posts come out at equal centres under the maximum, so you never get four bays at the limit and a stub on the end. A 4,320mm run comes back as five equal bays of 864, which is what would actually be made. The bars are then spaced to fill each bay and the tool reports the clear gap between them.

That means the picture and the numbers agree, and you can hand the numbers to a fabricator.

The 100mm sphere, and why it decides the bar spacing

If the railing guards a drop, the rule is that a 100mm sphere must not pass through any gap in it.

It is written as a sphere rather than as a gap on purpose, because it is about a small child's head and not about a tape measure. The practical effect is that 99mm passes and 100mm does not, so a tool checking "gap is 100 or less" is wrong by the millimetre that matters. This one spaces the bars to come in under it and shows you the figure it achieved.

This is a check on the figures you typed. It is not a specification, it does not size anything, and it says so on the result.

Choosing a style

• Vertical bars. Two rails and plain bars between them. The commonest, the cheapest to make, and the one that disappears into a view rather than competing with it.
• With a mid rail. A third rail at half height. Stiffer, so it suits a longer run, and it breaks up a tall panel.
• Estate railing. Bars stopping short of the top rail. Reads as park or parkland railing and suits a boundary more than a balcony.
• Hooped. A curve over each bay. More work to make, so more money, and it dates faster than plain bars.

Colour, and what it does to a wall

Dark grey and near-black recede, which is usually what you want in front of brick.

White advances and draws the eye straight to the railing, which is worth knowing before you commit: it looks smart in a photograph of a white rendered house and busy in front of red brick. A dark green or a dark red suits older property and stone. Drop the blend slider a little and the model sits into the photo instead of floating on top of it, which makes the comparison fairer.

Whether your wall can take it is the real question

Whether your wall can take it. That depends on what the wall is built of, how thick it is, what is under the coping and what fixings go in.

A railing on a single skin garden wall pulls on very little, and the fixing rather than the railing is what fails. That is a question for whoever is fitting it, and it is the one part of this job worth paying somebody to look at in person.