Look! Stars! In a floor! You can't feel them underfoot, and you can't see them when they're off, but they're really effective.

They light the whole room enough so you don't need to turn the main light on in the middle of the night too.

This is a simple vinyl floor on underlay. The addition of optical fibre is a bit fiddly, but not complicated. There is probably less than £30 worth of extra materials here to get the stars in place over the standard floor spend.

The idea is that the gaps in the floor boards beneath the underlay are big enough to run just a few fibres in (and the holes in the LVT are too small to see).

Optical fibre is simple and cheap. Here I used 0.75mm PMMA (see previous projects). Cut to (more than) length as required, and manage bundles of it however you can. This time I used a little convolute tube and masking tape as that's what I had lying around.

Keeping the fibres in a place with no pressure or wear from walking over the floor covering is crucial, and hiding the bundle under the skirting, threshold strip, and between the floorboard gaps was the easiest way for me.

This does mean that the fibre density is a little limited, but for this particular floor this wasn't a problem.

I've also used a cheap torch and step down regulator to power it from USB instead of the 1.5V battery it should have. Obviously this is done outside of the bathroom in a cupboard, keeping the bathroom electrics untouched!

It is a lot easier to install fibre here than on a real tile floor (see my other instructable), but that is probably the case for LVT over real tiles without the fibre too. Good luck!

Supplies

Install:

0.75mm PMMA optical fibre
Clear 2 part epoxy
Light source (torch & metal gland, or bespoke source)
Masking tape for cable management

Tools:

Long reaching spreading tool for epoxy (wooden skewer)
Scissors
Sand paper (and cardboard and tissue!)
Masking tape for marking

Step 1: Run the Fibre

The fibre for me runs from outside the bathroom, through a wall, along the gap under the skirting board, and then breaks out at a right angle to follow the floorboards.

1) Cut one or two rows of fibre with at least half a metre extra at each end, and run it, taping it down as you go. For me this was a bundle of 4-8 fibres.

It helps to temporarily light the source end, just vaguely, to help see the fibres. This also highlights any damage you do to the fibre whilst working.

Step 2: Mark and Drill

2) With the underlay fully cut to size and in place, cut and trial fit a row of tiles.

3) Measure and mark points along the floor board line on the tile, one mark for each star point / fibre (use some masking tape for ease of marking).

4) Next, with the tile in place, drill through the tile with a 1mm drill bit. Drilling through the tile, and through the underlay to mark it. Drilling at higher speed seems to give cleaner holes in the vinyl. You can do this with a standard hand drill and an extra chuck for holding small drill bits in a standard drill chuck, or as pictured by using a Dremel. Remove the vinyl after drilling to expose the underlay.

Step 3: Cut and Pull

Now you should have a floor board gap full of fibre (normally 2-4 fibres the full length of the bathroom in this case), and the underlay in place, but the tiles removed.

5) Cut a slot very roughly 15mm further than the star point, and 60mm closer to the wall around the point with a knife.

This slot is for the bend radius of the fibre, and should allow enough movement for install, but leave enough underlay so that the floor doesn't notice any missing. Resize it if you feel you need to, for larger diameter fibre or bigger floor board gaps for example.

6) Carefully pull a single fibre through this slot as shown in the picture. Repeat for the whole row.

Check the run as it is easy to pull too much fibre and not leave enough to make it back to the light source.

Step 4: Poke

7) Now placing the tile as in place possible, but still with working room underneath, poke the fibres through the holes in the tiles.

This gets a little awkward trying to hold the tile in place, and not letting it fall and break the other fibres.

Once the fibres are all poked through, make sure the slack beneath the vinyl is such that the fibre would slot into the underlay gap and between the floor boards when the vinyl is down.

Once again make sure the fibre run is still in place.

Step 5: Stick

Sticking is by far the most fiddly bit.

8) With some clear two part epoxy pull the fibre back down underneath the vinyl by the same distance as the thickness of the vinyl (if the vinyl is 5mm thick, pull it down by 5mm). Then pack epoxy round the fibre, poke it back up through the vinyl beyond its final resting place, and then pull it back down into the correct place - aiming to fill the barrel of the drilled hole with epoxy.

Try to make sure each hole is completely re-sealed from the underside of the vinyl, but not with so much epoxy that it won't fit into the gap between the floor boards.

Lighting the fibres helps here especially.

Step 6: Wait

Make sure the fibre run and position is definitely in the right place (both at the end and along the run), and the tile is as fitted as it can be.

9) Snip the fibres with some scissors close to vinyl level (as short as you can).

10) After each row, wait for the epoxy to cure, keeping the vinyl raised to prevent the epoxy sticking to the underlay or the floor. A little movement between vinyl tiles is to be expected once everything is in place.

Each tile will be different. I had some with two fibre rows in them, and some points were simply hard to reach underneath, especially the last row. It might be worth avoiding fibres in the last row adjacent to the wall due to access.

11) After the epoxy is cured, fully lay the vinyl row. Making sure its properly clicked in place without moving the tiles enough to disturb the fibres may be tricky.

Step 7: Flush

Once rows are down, you'll have a spiky floor. It is time to get the fibres flush with the floor.

12) Use some cardboard to protect the floor and sand each fibre down.

This is an easy way to get the fibre much shorter, but still not short enough for bare feet.

13) Use tissue to protect the floor, and very small action to sand them flush.

The tissue will rip straight away where there is something to abrade, but slip over the smooth floor, at least for a bit. A larger sanding action will increase the likelihood of a sanded floor, which is probably not the look you want in a vinyl floor. Don't use the same tissue hole for too long.

Step 8: Terminate the Fibres

Now it's time to deal with the other end of the fibre. You've probably realised that any old light down any old fibre will work. To make it work well, all of the fibre ends need to be flat and smooth (not just snipped) and the light source needs to be pointing straight into them.

14) To terminate the fibres at the light source, bundle and secure the the fibres together and cut the fibres with a hot knife (or blowtorch heated knife blade)!

Polish with the finest (>240grit) sand paper you have and once dusted off, the light should be able to enter all the fibres well and evenly.

15) Connect the light source.

A cheap torch that focuses down to a very narrow beam works well (with a PSU tacked in to replace the batteries). This is enough to light my entire floor, which uses about 150m of fibre in total. It will probably cost less than £6 a year to leave it on full time, (which obviously it isn't).

Using a small metal cable gland allows you to bundle and secure the fibres, and allows you to use the hot knife to cut very close to the gland to keep the bundle of ends tight and ready for the torch.

You can also purchase proper light sources specifically for the job, which can have effects and other functions. In this case, the gland is normally replaced with a ferule, and project budgets change.

Step 9: Light Things Up!

The finished floor should look like any other floor when the stars are switched off. The tiny fibres are transparent / dark and can't really be seen without close inspection.

When it is on, it looks like stars!

If you have a vinyl floor to lay, I hope you get to try it out. If you have a real tiled floor to lay, take a look at my last bathroom project where I did just that, and explain the principles behind that and this in more detail. Obviously if you have another floor that you manage to fibre, we'd all love to hear about how you went about it too.