Savvy Spex: DIY Internal Windows: HOW TO DO IT

In order to make the window even and symmetrical you need to fit wooden planks inside your recess. It's not a hard job but you need to find the right size of wood for your window or have it cut to size. That depends on how deep your recess is. Sometimes it's more, sometimes less. Ideally that should be 10 cm (or at least 7-8 from the nearer pane). The wall recess will also probably be a bit out of whack and so the wood will make it nice and smooth.

WOODEN FRAME IN RECESS

Measure the length of the recess and fit the wooden planks inside. Drill through so you make a mark on the wall beneath.

Make sure you mark the beam as well

because you have to take it out and put it back in place after you drill the holes in the wall. If you place it the other way round, the holes won't check.

Take the beam away and drill the holes in the wall

Insert plastic plugs in the drilled wholes and them and cut with knife

Fix the wooden beams along the walls and make them level. Make sure that all opposing sides have the same length. If they don't move them until they do.

Walls are not always level

The recess was narrower on one side

It doesn't have to be tight, you will simply fill the gaps later

Walls are often not even

Finished frame should look something like this

Mount the middle beam.

Measure the exact middle of the window width and place a thick middle beam there. It can be easily screwed with L shaped angle brackets to the wood.

The middle beam in good quality pine would will cost about $50.

Again, make sure that the opposing sides are the same length and you have right angles (or near right angles everywhere)

The complete framed window should look something like this

Once the beams are fixed to the wall, fill the gaps using paint over sealant, for instance this one.

FITTING THE STEEL TRIM

When it's dry you may proceed to attaching steel L-shaped trim.

I found it in Bunnings, relatively cheap.

A few remarks there though. It's perforated on one side but sometimes the perforations are on the longer side of the "L" and sometimes on the shorter side of the "L". Make sure you get the same rods for the whole circumference of your window.

Now, how far from the wall should you fix them? That depends what thickness of the glass you chose.

Go to the link Choosing thickness to find out. Than come back here.

I chose acryclic that is 6 mm thick.

Plastic cap profiles will be on the edges which will further add to it. I figured I needed 11-12 mm from the wall for 6 mm thickness.

If you choose 4.5 you have to subtract say 2mm from it and also choose the right plastic cap profiles.

Tip: You can make yourself a little model of your window by using a sample from your plastic sheet supplier (some of them will be listed here later)

A little "model" of your window made of the acrylic sample

Use this as a measure to find the right distance from the edge.

This way you can see how your window will actually look

Metal L-shaped trim

You're looking for this disc

The perforations in the metal trim are not perfect and need to be drilled. Just drill the wholes that you will use (say 20 cm or so apart)

Correcting holes in the steel trim

Life saving tip: You don't cut the metal trims by a metal saw. It's painfully slow and noisy. Use a large tin snip (pliers) instead. It works like magic. Cut both sides and then just bend several times and pieces will fall apart.