How to measure for blinds properly.

First decision: inside or outside mount.

Everything else follows from this, and it is a decision about the window, not about taste.

Inside mount (in the reveal).

The blind sits inside the window recess. It looks built in, keeps the sill and the architrave visible, and suits square, deep reveals. It needs enough reveal depth to take the brackets, which is typically 40mm to 70mm depending on the product, and it needs the opening to be reasonably square. The trade-off is a small light gap down each side, because the blind must be slightly narrower than the opening to run freely. That gap is why an inside-mounted blockout blind in a bedroom is dim rather than dark unless you add side channels.

Outside mount (face fixed).

The blind is fixed to the architrave or the wall above the window and overlaps the opening. It is far more forgiving: it hides an out-of-square opening, covers the whole window so light does not leak at the edges, works where the reveal is too shallow for brackets, and leaves the full pane of glass usable because the blind sits clear of the frame. It makes the window look slightly larger, which is usually an improvement. In older homes around central Pakenham, Koo Wee Rup and Nar Nar Goon, an outside mount is the right answer far more often than people assume.

How to take the measurements.

Use a steel tape. A cloth or plastic tape stretches and will cost you 3mm to 5mm, which is enough to matter. Work in millimetres throughout, and write the numbers down against a room and window description as you go, not from memory afterwards.

Inside mount.

• Measure the width at the top of the reveal, at the middle, and at the bottom. Record all three.
• Measure the drop at the left edge, the centre and the right edge. Record all three.
• Measure the reveal depth from the face of the glass to the front edge of the reveal, so bracket depth can be checked.
• Note any window handle, lock or opening sash that a blind would foul.

Outside mount.

• Measure the full opening width, then add at least 50mm of overlap on each side.
• Add at least 100mm above the opening for the roll or headrail.
• Decide where the bottom rail should finish: to the sill, or past it to the floor.
• Check what is behind the fixing point. Plasterboard alone will not hold a wide blind and needs the right anchor or a fix into timber.

One rule that matters more than any of the above: do not deduct anything yourself. Give the raw numbers to the supplier and let them apply their own manufacturing allowances. Deducting a clearance and then having the factory deduct theirs on top is one of the most common ways to end up with a light gap down both sides of a brand new blind.

The mistakes that cost a whole blind.

• Measuring the width once. Openings settle. A window that is 1500mm at the head can be 1488mm at the sill in a forty year old brick home. Order to the head and the blind will not enter the bottom of the reveal.
• Deducting your own allowance. Covered above. Give raw numbers.
• Forgetting the handle. A window handle or a lock protruding into the reveal will stop a blind rolling flat, and it is only obvious once the blind is up.
• Ignoring reveal depth. The width can be perfect and the blind still will not mount inside if the reveal is 30mm and the bracket needs 60mm.
• Measuring off a plan. In a new build, reveal sizes move 5mm to 15mm between drawing and finished house. See blinds for new builds.
• Not checking which way a sliding door opens. A vertical blind must stack on the correct side or it fouls the opening leaf every time.
• Assuming two identical-looking windows are identical. They routinely differ by several millimetres. Measure each one.

Why a free in-home measure beats doing it yourself.

The blunt reason is where the risk sits. A made-to-measure blind is built to the numbers on the order, so a customer-supplied measurement that is wrong produces a blind that is wrong, and that is not a warranty claim anywhere in the industry. When we measure, we own the numbers, and if a blind does not fit, that is our problem to fix.

The more useful reason is everything a tape measure does not tell you. At a measure we check bracket depth against the reveal, handle and lock clearances, whether the architrave will take a fixing or whether there is only plasterboard behind it, which way each sliding door opens, how square each opening really is, and whether a very wide window should become two blinds on one headrail rather than one sagging blind. We also bring the fabric books, so you can hold a sunscreen against your own glass at the time of day the room is worst, which is the only reliable way to choose an openness factor. That decision is covered in blockout versus sunscreen.

What happens at the appointment.

We come to your house anywhere in Pakenham and the Cardinia Shire, usually within a few days of you calling. Allow around 45 minutes for an average home, longer for a larger place in Pakenham Upper where few windows match. Every opening is measured and recorded, mount type is agreed room by room, fabrics are chosen against your own light, and you get a written itemised quote with the fabric names on it. Manufacture is typically two to three weeks, then a single install visit. Current pricing sits on the Pakenham cost guide.

Frequently asked questions.