How to calculate equal stair spacing and deck/porch.
The final step in the staircase installation is getting perfect spindle spacing between the newel post.
The U.K.'s spindle spacing needs to be less than 100mm apart in order to prevent toddlers from falling through them or getting their head through.You can use a 100mm ball to test the gap.
If your spindles are turned, the gap will get wider at points where they become narrower.
If you are unsure of the maximum permitted dimensions in your area, always check with your local council/building inspector.
If you haven't already done so, use the formula here to calculate how many spindles are required in your staircase.
The picture shows how I calculate the spindle spacing's.This is the most accurate method I have found and it will become clear as we go through it.
I cut them all to length and fit them together at one end first so they are easy to install.I can fit one, glue it, nail it and move on to the next one with ease.
Whether you are installing balusters on a staircase, balcony, garden deck, veranda, porch, anywhere else, the theory is the same.
I use my nail-gun to fix the base rails and hand rails.The advantage of a nail gun is that the heads of the nails are buried under the timber so they can easily be filled with natural wood coloured filler.
The handrail can bebowed up if you use a hammer and nails to nail the top of the balusters to the handrail.This problem can be avoided if a nail-gun and 600mm spirit level are used.
If you don't have a nail-gun, you can use 30mm panel pins to fix the balusters.To make sure the hand rail is straight, you need to keep an eye on it all the time.If the hand rail and base rails are going to be painted, you could fix a brace to keep it straight while you work on it.
Put the spindles against the post and each other at the bottom of the run.Square spindles are easy to cut, but turned ones need more care.
To set your saw to the correct angle, try to keep the turned section central or slightly higher than the central within the spindles length.
It is possible to mark the angles/length top and bottom before cutting and checking it.Rather than thinking after.
If you have a saw and bench like mine, you can use a stop above to cut them all the same length.
If not, use one spindles as a template and be careful when transferring the length onto the other spindles.If they are not flush with each other, the length will be affected.
This is the same as the diagram before, you can see in the blurry picture above that I had to hang a long spirit level to the inside edge of the top newel post for a perfect horizontal measurement.
If you have a long run of spindles and an odd number of them, you can find the exact location of your staircase run and fix them there.Two equal but separate smaller runs will work with one top and one bottom.
You could put a screw in the top and bottom of the spindles to make sure they are strong enough to hold the handrail straight while you fix it.
You should have more spacing than there is.If you have 10 spindles, take the measurement from step 2 and divide it by 11.This will show you the horizontal distance between each spacing.In the UK, you can't have a spacing of more than 100mm between the spindles because a child could fall through or even get their head through it.
The gaps will look stupid if they are too large or small, so I always aim for around 90mm spindle spacings.If the answer is more than 100, cut another spindle and add it to the others.If you have a gap that complies with your local regulations, add or remove the spindles.The 70-80mm looks good and ensures that the gaps won't exceed 100mm.
I will work out the spacings for each run before I glue and nail them.If there is a lot of variation between sections, I may try and get the spacings as close to each other as possible by removing one of the sections with the smallest gaps.
If you want to cut a piece larger than the spacing strip, you can do it with the angle of the staircase pitch.A tape measure or ruler can be used to find the correct distance away from the top newel post.If the hand and base rails don't fit tightly, pin the bottom of the spindle so it stays put.Like in the picture below.Use a sharp pencil to mark the length of the spacer.
With the chop-saw still set to the staircase pitch, cut the angle on one end of the spacer and then use a razor sharp pencil to cut to length.
You have an identically matching pair if you use it to mark another.Put these in the grooves of the hand and base rail and see if they fit between the post and the spindle.
If they're okay and leave the correct spacing in step 2, trim or cut two new ones until you are happy with the length.
If you are working on a diagonal run and your spacing timber is a different thickness for the base rail to the hand rail, you will need to calculate the length for each separately.A thicker strip needs to be slightly longer than a thinner strip.
Pick up an off-cut of timber and a good woodworking tool.Lock the Chop-Saw blade down low and hold the spacer up to the blade to make sure it is flat against the saws fence.Don't push the blade against it.
The timber can be off-cut if the spacer is held up to the blade.
It will act as a stop for making accurate repeat cuts.You only need to cut a third of the amount needed for now.
Cut a test pair and make sure they are perfect before cutting more.When cutting these, make sure the material is flat against the fence, there is no sawdust in the way, and you bring the saw blade down slowly, letting the blade cut.You will lose accuracy if you are too fast.
A finish nail gun or 30mm panel pins can be used to fix the first two spacers.I rub the two together to spread the glue before sliding them in.
If you slide them back and forth in the grooves, they will be perfectly flat against the newel post.
The nail heads should be punched under the surface so they can be filled later.
If the staircase is hardwood and not being painted, I'll fill these with wood coloured filler myself for a neater finish.The customer can't see the tiny nail holes when they come home, so it looks more impressive to them.
If you want to cover the previously fitted spacers, you need to glue the top and bottom of the spindle to the base rail.
If you position it in the base-rail, you may be able to slide it back and forth easily.
As mentioned, it's important to keep an eye on the handrail as you fill it up to make sure it doesn't start to bow upwards.The chances of that happening are pretty much eliminated by using a nail-gun and holding the handrail firmly in place.
Stop and do step 2 when you have fitted a third to half of the spindles.By the time you get to the bottom you'll be 20mm out and it will look rubbish.You've probably seen a staircase where the spacings are equal until one end is larger than the other.
If you need to adjust the spacers up or down, do it while there is time.Now you can start fitting from the bottom up.It's better to have that slight variation in the middle of the run where it will blend in and be less noticeable than it is at the post.