Extended Spring Sale โ€“ Up to 20% off blinds that cut your energy bills!ย  Ends Sat, 31 Oct 2026.

1800 482 777
SHOP NOW
Coverlight DIY  /  Installation guide  /  Outside mount, Underroll

Install your Coverlight DIY blind Outside mount, Underroll

Step-by-step instructions for installing a manual underroll blind on the face of the window architrave. Follow the steps in order and you’ll be done in under an hour.

Prefer it on one page? Open the quick install guide (PDF).

What you’ll need
From your toolbox
  • Power drill
  • 2.5mm drill bit (timber, metal or plaster)
  • P2 Phillips screwdriver
  • Spirit level
  • Pencil
  • Step ladder
Estimated time
Under an hour
Per window. Slightly faster than inside mount.
Step 0

Before you begin

This guide covers installation into timber, metal frames and plaster. Other surfaces have a slightly different process.

Installing into masonry, brick, concrete or tile

If you’re mounting onto a masonry surface, you must use the provided wall plugs. This requires a different drill and drill bit.

Follow the main installation guide, but when you reach a “pre-drill” step, use the method below instead.

Additional tools needed

  • Hammer drill (or a drill with a hammer function)
  • 6mm masonry drill bit
  • 6mm spear-tipped (or diamond-tipped) tile drill bit (if drilling on tiles)
  • Hammer
  • Masking tape

Special instructions for tiled surfaces

If your mounting surface is tile, use this technique to avoid cracking the tile:

  1. Place a piece of masking tape over each marked hole position. This stops the drill bit from slipping.
  2. Insert a 6mm spear-tipped tile drill bit into your drill.
  3. Important: ensure the hammer function on your drill is turned off.
  4. Drill slowly and with steady pressure through the tile.
  5. Once you’re through the tile and have hit the brick or concrete behind it, stop.
  6. Switch to your 6mm masonry drill bit and proceed with the masonry method below.

Masonry drilling method

  1. Mark your holes: position your frame component and mark the screw locations with a pencil.
  2. Drill for plugs: using your hammer drill and a 6mm masonry bit, drill a hole at each mark, slightly deeper than the wall plug (approx. 30mm).
  3. Clean the holes: clear all dust with a vacuum or brush. Crucial for a secure fit.
  4. Insert the plugs: push a wall plug from your masonry kit into each hole and tap gently with a hammer until flush with the wall.
  5. Secure the component: align your frame piece with the plugged holes and drive the screws in with a hand screwdriver.
Installing into plaster

For a secure installation into a plaster wall, fasten your screws into the solid timber or metal stud behind the plasterboard.

How to know if you’ve missed a stud

When you pre-drill your pilot holes, you’ll feel one of two things:

  1. Solid resistance: the drill pushes against firm resistance. You’ve hit a stud and can drive your screw directly into this hole.
  2. Sudden give: the drill bit pushes through the plaster with almost no resistance. You’re in a hollow section. A standard screw won’t hold here. Use a suitable plaster plug.

What to do if you miss a stud

Buy suitable plaster plugs (also called drywall anchors) from your local hardware store. Choose an anchor rated for the weight of your blind and follow the manufacturer’s instructions.

Get ready

Preparation

Gather your tools, check your kit, and clear your workspace before you start.

From your Coverlight box

  • Check all parts against the included checklist
  • If you selected a masonry surface, ensure you have your masonry kit

Prepare your workspace

  • Clear the area in front of your window
  • Unpack your blind components and inspect them for any transit damage
12 steps

Installation steps

Follow these in order. Each step builds on the last.

1 Remove the blind roll
  1. Using a P2 screwdriver, unscrew and remove the front pelmet cover.
  2. Retract the pin on the idler end of the blind roll.
  3. Carefully lift the idler end out first, then slide the entire roll out of the headbox.
  4. Set the roll and front cover safely aside.
Stage 1
Stage 1
Stage 2
Stage 2
Stage 3
Stage 3
Stage 4
Stage 4

Watch: the idler pin and removing the roll

What is the idler pin on a roller blind? | Coverlight DIY

What is the idler pin?

How to remove the blind roll from the headbox | Coverlight DIY

Removing the blind roll

Parts reference

AFront pelmet
BRear pelmet
CFabric roll
DLeft side channel cover
ERight side channel cover
FLeft side channel
GRight side channel
HU-channel
ILeft front cover
JRight front cover

2 Apply light seal to the pelmet
  1. Remove the protective film from the rear pelmet component.
  2. Use the provided alcohol wipe to thoroughly clean all surfaces of the pelmet where the foam will be applied.
  3. Apply the top rear seal:
    • Measure the rear top edge of the pelmet.
    • Cut a piece of expanding foam to this measurement.
    • Peel the adhesive backing and apply the foam to the top rear edge, covering the holes in the pelmet.
  4. Using the 3mm Allen key or screwdriver, pierce the Light Block from the top through the holes.
  5. Apply the pelmet side seals:
    • Measure the height from the bottom of the seal to the bottom of the rear pelmet.
    • Cut a piece of foam 3-5mm longer than this measurement.
    • Apply the foam so it sits flush against the top seal, creating a neat butt join in the corner. This will leave a 3-5mm overhang at the bottom.
    • Repeat for the other side of the pelmet.
Stage 1
Stage 1
Stage 2
Stage 2
Pro-tip: applying the foam Press down firmly along its entire length to ensure a strong bond. Do not stretch the foam as you apply it.

3 Mount the pelmet
  1. Mark a level line: use your spirit level to draw a faint, perfectly level pencil line on the wall or architrave where the top of the pelmet will sit.
  2. Position & mark holes: place the pelmet on the wall, aligning its top edge with your pencil line and centring it over the window. Mark your screw locations through the pre-drilled holes in the top of the pelmet.
  3. Pre-drill & secure: remove the pelmet, pre-drill pilot holes on your marks to a depth of 20-25mm, then reposition the pelmet and securely fasten it to the wall.
Pro-tip: controlling drill depth Measure 20mm from the tip of your drill bit and wrap a piece of masking tape around it. Drill into the frame until the edge of the tape is flush with the surface.
Warning: drilling into plaster If your drill bit suddenly pushes through with no resistance, you’ve missed the stud. Do not drive a screw into this hole. Use a plaster plug. See the “Installing into plaster” guide at the top of this page.

4 Apply light seal to the side channels
  1. Take both side channels and remove their front covers by rotating them outwards. Set the covers aside.
  2. Use the provided alcohol wipe to clean the rear surfaces of one side channel.
  3. Apply the side channel rear seal:
    • Measure the full length of the back of one side channel.
    • Cut a piece of foam to this exact length.
    • Peel the backing and apply the foam to the rear of the channel, ensuring it sits flush with the bottom edge.
    • At the bottom of the side channel, measure between the foam and the inside edge of the side channel.
    • Cut a piece to this exact length.
    • Peel the backing and apply the foam to the rear of the channel, ensuring it sits flush with the bottom edge.
    • Using the 3mm Allen key or screwdriver, pierce the Light Block from the top through the holes.
  4. Repeat for the second channel: repeat steps 2 and 3 for the remaining side channel assembly.
Stage 1
Stage 1
Stage 2
Stage 2
Stage 3
Stage 3
Stage 4
Stage 4
Stage 5
Stage 5
Stage 6
Stage 6
Stage 7
Stage 7
Pro-tip Press the foam down firmly along its entire length for a strong bond. Don’t stretch it as you apply.

5 Secure the first side channel (the anchor)
  1. Attach the channel to the pelmet until it locks into place.
  2. Place your spirit level against the face and front edge of the channel. Adjust it until it is perfectly plumb (vertical) in both directions.
  3. With the channel held in its plumb position, pre-drill and securely fasten it to the wall with all of its screws.
Stage 1
Stage 1
Stage 2
Stage 2

6 Pin the second side channel
  1. Attach the channel to the other end of the pelmet and let it hang.
  2. Make the channel plumb with your spirit level.
  3. Pre-drill and install only the top screw. The channel should be held in place but still able to pivot slightly at the bottom.
Stage 1
Stage 1
Stage 2
Stage 2
Stage 3
Stage 3
Stage 4
Stage 4
Pro-tip: controlling drill depth Measure 20mm from the tip of your drill bit and wrap a piece of masking tape around it. Drill into the frame until the edge of the tape is flush with the surface.
Warning: drilling into plaster If your drill bit suddenly pushes through with no resistance, you’ve missed the stud. Do not drive a screw into this hole. Use a plaster plug. See the “Installing into plaster” guide at the top of this page.

7 Position the bottom frame
  1. Take the bottom U-channel and butt one end firmly against your first, fully secured “anchor” channel.
  2. Swing your second, “pinned” side channel inwards and press it snugly against the other end of the bottom U-channel.
  3. Perform a quick check: place your spirit level on the bottom U-channel. It should be level, confirming your frame is square.
  4. Mark the position: with everything held in place, use a pencil to lightly mark the position of the U-channel on the window sill.
  5. Secure the U-channel: swing the second side channel out of the way. Clean the sill, remove the tape backing from the U-channel, and press it firmly into place along your marked line.

8 Secure the final frame
  1. Swing the second side channel back into place so it sits snugly against the now-fixed bottom U-channel.
  2. Pre-drill and securely fasten this final channel to the wall with all its remaining screws, using a hand screwdriver.
Stage 1
Stage 1
Stage 2
Stage 2
Stage 3
Stage 3
Pro-tip: controlling drill depth Measure 20mm from the tip of your drill bit and wrap a piece of masking tape around it. Drill into the frame until the edge of the tape is flush with the surface.
Warning: drilling into plaster If your drill bit suddenly pushes through with no resistance, you’ve missed the stud. Do not drive a screw into this hole. Use a plaster plug. See the “Installing into plaster” guide at the top of this page.
Spring or motor? For spring (manual) blinds, continue to Step 9 below. For motorised blinds, follow Step 9 first to install the roll, then see the motor programming guide.

9 Install the zero-touch spring blind roll

With the frame fully installed, you can now insert the blind roll. Follow these steps carefully to ensure the zero-touch spring mechanism works perfectly.

Important: check spring preload before starting Before installation, check your blind roll. The bottom rail should be no more than 100mm from the main fabric roll. If it has unrolled further, simply rotate the roll by hand to wind the extra fabric back on. Ensure the retaining pin on the spring end remains facing outwards.
Critical: do not remove the retaining pin The retaining pin holds the spring’s tension. Do not remove this pin at this stage. It must only be removed after the blind roll is fully and securely installed in its brackets. Removing the pin prematurely will cause the spring to unwind and will permanently damage the mechanism.
  1. Insert the spring end first: identify the spring end of your blind roll. You’ll see a flat tab and a small retaining pin. With this retaining pin facing outwards (towards you, not the glass), slide the tab securely into the corresponding bracket inside the pelmet. This end must go in first.
  2. Insert the idler (pin) end: check that the retractable locking pin on the other end of the roll is pushed in (retracted). Now lift this end and guide it into its bracket inside the pelmet.
  3. Engage the idler pin: once the roll is in place, release the retractable idler pin so it extends and locks securely into the bracket. You should hear or feel it click into position.
  4. Confirm the roll is secure: before activating the spring, gently hold the blind roll and try to move it back and forth. There should be no significant movement.
  5. Activate the spring: now pull the retaining pin out from the spring end to engage the zero-touch mechanism. There’s a dedicated storage hole on the end cap where you can place this pin.
  6. Test the operation: test the zero-touch spring action by gently pulling the bottom rail downwards and guiding it back up. The blind should glide smoothly and hold its position wherever you stop it.
  7. Engage the bottom lock: when the blind is fully lowered, the bottom rail is designed to lock into the bottom U-channel.
Stage 1
Stage 1
Stage 2
Stage 2
Stage 3
Stage 3
Stage 4
Stage 4
Stage 5
Stage 5
Stage 6
Stage 6
Stage 7
Stage 7
Stage 8
Stage 8
Stage 9
Stage 9
Stage 10
Stage 10
Stage 11
Stage 11
Stage 12
Stage 12
Stage 13
Stage 13
Stage 14
Stage 14
Critical: future removal of the blind roll To prevent permanent damage, you must follow this specific procedure to disengage the spring tension before removing the blind roll.
  1. Roll the blind all the way up to the top.
  2. Take the retaining pin from its storage spot on the end cap.
  3. While the blind is near the top, gently move it up and down slightly until you can push the retaining pin all the way in to the hole on the spring end.
  4. Only once the spring tension is locked by the pin can you safely retract the locking pin on the idler end and remove the blind roll.
Failure to follow this procedure will cause the spring to rapidly unwind, permanently damaging the mechanism. This is not covered under warranty.

Watch: removing the blind roll

A short demo of the idler end removal procedure described above.

How to remove the blind roll from the headbox | Coverlight DIY

10 Install the final covers
  1. Re-install the side channel front covers:
    • Take the long front covers you set aside earlier.
    • Re-install them by engaging the inner edge into the side channel first, then snapping the outer edge securely into place. Start from the bottom and work your way up.
  2. Install the bottom corner covers:
    • Take the two small corner cover pieces.
    • Align one cover with the join where the side channel meets the bottom U-channel.
    • Slide it over the end of the bottom U-channel until it sits flush, neatly covering the join.
    • Repeat for the other side.

11 Attach the front pelmet

This is the final step to complete the look of your new blind.

  1. Prepare the pelmet: just before you attach the front pelmet, carefully peel off the protective plastic film from its surface. Doing this now prevents the film from being trapped and avoids scratching the finish during installation.
  2. Angle and position the top: hold the front pelmet cover at a slight angle. Insert the top lip of the pelmet into the gap between the top of your window frame and the main pelmet.
  3. Pivot the bottom into place: once the top is securely in position, pivot the bottom of the pelmet cover backwards towards the blind until it sits flush and firm against the main headbox, creating a seamless look.
  4. Fasten the retaining screws: insert the provided colour-matched screws into the pre-drilled holes on the front face of the pelmet. Tighten them until they’re firm, but be careful not to over-tighten.

12 Final inspection for light leaks

Congratulations on completing the installation. The final step is to check the light-blocking performance.

A. How to perform the check

  1. Fully close your Coverlight blind until the bottom rail is locked in the U-channel.
  2. Darken the room by closing the door and turning off all interior lights.
  3. Allow your eyes to adjust to the darkness for a few minutes.
  4. Inspect the perimeter of the blind frame, looking straight on at the edges and corners.

B. What to look for and what to expect

It’s important to understand the two different areas where you might see light.

1. Light around the outside of the frame

What you might see: some small slivers of light between the back of your blind frame and the wall surface, especially if the wall is not perfectly flat.

What to do: nothing. The expanding foam seal you installed is designed to slowly swell and compress against the wall to fill these gaps. Allow up to 7 days for this to happen.

2. Light within the frame

What to look for:

  • Pinpricks of light coming through the middle of the fabric itself, away from the edges
  • Significant or uneven gaps between the moving blind fabric and the inside of the side channels

What to do: if you notice light leaks within the frame that aren’t related to the outer foam seal, refer to our online troubleshooting guide or contact our support team.

โœ“
All done

Enjoy your blackout

Your new Coverlight blind is fully installed.

Going motorised? Set up your motor โ†’ View FAQs
0
0
Your Cart
Your cart is emptyReturn to Shop
Add Another Blind and Accessories