How to Replace Vertical Blind Weights and Chains
Updated: Aug 11
If the bottom of your vertical blinds looks uneven, twisted or untidy, the problem may be much easier and cheaper to fix than you think.
The bottom weights and linking chains help vertical blind slats hang straight and remain evenly spaced. Over time, weights can become damaged or lost and the small clips on the bottom chain can break.
Fortunately, both parts are normally straightforward to replace without replacing the complete blind.
In this guide, we'll explain how to identify the correct vertical blind weights and chains, how to fit them, and when you might want to consider changing from chained to chainless weights.
What Do Vertical Blind Weights Do?
Vertical blind weights sit inside the pocket at the bottom of each fabric slat, sometimes called a vane or louvre.
Their weight helps keep the fabric hanging straight and reduces twisting and movement.
Traditional vertical blind weights also have small fixing points at each side. A bottom chain clips onto these points, linking the slats together and helping to maintain even spacing.
If a weight or chain becomes damaged, you may notice:
Slats hanging unevenly
Slats twisting more than usual
Gaps between the bottom of the slats
Broken or disconnected chain
Missing weights
Individual slats moving independently
The bottom of the blind looking generally untidy
These problems can often be repaired very inexpensively.
Step 1: Check Your Vertical Blind Slat Width
Before ordering replacement weights or bottom chain, the first thing to establish is the width of your vertical blind slats.
Two of the most common sizes are:
89mm (3.5 inch)
127mm (5 inch)
Measure straight across the width of one fabric slat.
This measurement is important because 89mm and 127mm blinds use different sized weights and different spacing between the clips on their bottom chains.
Don't order purely by appearance. Check the actual slat width first.
Step 2: Check Whether You Have Chained or Chainless Weights
There are two common types of vertical blind bottom weight.
Weights for Use With Bottom Chain
Traditional vertical blind weights have fixing points that allow a separate bottom chain to clip onto them.
The chain runs across the bottom of the blind, usually on both sides of the slats.
This keeps the slats evenly spaced and gives the bottom of the blind a uniform appearance.
Chainless Vertical Blind Weights
Chainless weights don't require a separate linking chain.
They can provide a cleaner appearance and eliminate the problem of bottom-chain clips becoming broken or disconnected.
If you are replacing your existing weights, you therefore have an opportunity to decide whether you want to retain the traditional weight-and-chain system or change to chainless weights.
Do I Need to Replace All My Vertical Blind Weights?
Not necessarily.
If only one or two weights are missing or damaged and you can obtain replacements that match the existing weights, you may only need to replace those individual items.
However, if the existing weights are old, different in design or several are damaged, replacing a complete set can give a more consistent result.
The important thing is that the replacement weight is the correct size for the slat.
Step 3: Remove the Damaged Vertical Bottom Chain
If you are retaining a chained system, remove any damaged bottom chain.
The chain is normally attached using small clips that fit onto the fixing points on the bottom weights.
Work along the blind carefully, unclipping the chain from each weight.
If only a small section is damaged, it may be possible to replace part of the chain rather than the entire length - not recommended.
However, older plastic chain can become brittle with age. If several clips have started breaking, replacing the complete chain may save you having to repair another section shortly afterwards.
Step 4: Remove the Old Vertical Blind Weights
The weights sit inside pockets sewn or formed into the bottom of the fabric slats.
Carefully slide the old weight out of the pocket.
Take care with older blind fabric, particularly if it has become brittle or weakened with age.
If you're replacing several weights, keeping one of the originals beside you can also be useful for comparison.
Step 5: Insert the Replacement Weights
Slide the new weight into the bottom pocket of each slat.
Make sure:
The weight is sitting fully inside the pocket
It is the correct way up
The chain fixing points are accessible
Each weight is sitting at approximately the same height
Once all the weights are fitted, allow the slats to hang naturally before attaching the new chain.
Step 6: Fit the New Vertical Blind Bottom Chain
Clip the bottom chain onto the fixing point of the first weight and work your way across the blind.
The chain should connect each weight while allowing the slats to hang naturally.
Don't pull the chain tight.
The spacing of the clips should correspond with the width of your vertical blind slats, which is why it's important to choose 89mm chain for 89mm slats and 127mm chain for 127mm slats.
Once one side is complete, repeat the process on the other side of the blind if your system uses chain on both sides.
How Much Vertical Blind Bottom Chain Do I Need?
The easiest approach is usually to look at the number of slats or weights you need to connect rather than simply measuring the width of the window.
Bottom chain is manufactured with clips spaced to suit the corresponding slat width.
Make sure you order the correct type for your 89mm or 127mm vertical blind and enough links to connect all the weights you need.
If you're replacing an existing chain, count the number of connections required before ordering.
Should I Change to Chainless Vertical Blind Weights?
This comes down largely to personal preference.
Traditional weights and chains have been used successfully on vertical blinds for many years. The chain helps maintain consistent spacing between the slats.
The disadvantage is that the small plastic clips can become damaged, particularly if the bottom of the blind is caught, pulled or knocked.
Chainless weights remove the need for this separate bottom chain.
This can make them particularly attractive if you're tired of repeatedly replacing broken bottom-chain clips or simply prefer a cleaner appearance.
If changing to chainless weights, make sure you purchase the correct weight size for your slats.
Bottom Chain or Control Chain – What's the Difference?
This is an important distinction when ordering replacement vertical blind parts.
The bottom chain connects the weights at the bottom of the fabric slats.
The tilt or control chain is part of the operating system at the top of the blind and is used to rotate the slats.
They perform completely different jobs.
If your slats aren't rotating correctly when you operate the controls, replacing the bottom chain is unlikely to solve the problem.
If the slats rotate correctly but are disconnected or uneven at the bottom, the weights or bottom chain are more likely to be the issue.
Why Does My New Bottom Chain Not Line Up?
If the clips on a replacement bottom chain don't correspond with the spacing of your slats, check the slat width.
You may have ordered 89mm chain for a 127mm blind, or vice versa.
Measure one of the fabric slats from side to side and compare it with the chain you've purchased.
Correctly sized bottom chain should naturally correspond with the spacing of the slats when the blind is hanging normally.
What If My Vertical Blind Still Hangs Unevenly?
Weights and chains aren't responsible for every vertical blind alignment problem.
If you've replaced the damaged bottom components but one or more slats are still hanging incorrectly, check:
Whether the fabric slat is correctly fitted
The hanger at the top of the slat
Whether any hangers are broken
Whether the carrier/truck inside the headrail is damaged
Whether the slats are all correctly aligned
Whether the fabric itself has become distorted
This is where identifying the symptom before replacing parts can save both time and money.
Is It Worth Repairing Vertical Blind Weights and Chains?
In most cases, absolutely.
If the headrail and fabric slats are still in reasonable condition, replacing a few weights or a damaged bottom chain is normally far cheaper than replacing the complete blind.
These are simple components and are designed to be replaceable.
A broken chain or missing weight doesn't mean the blind has reached the end of its useful life.
Before Ordering – Quick Checklist
Check:
Slat width: 89mm or 127mm?
Weight type: Chained or chainless?
How many weights: One or two replacements, or a complete set?
Bottom chain: 89mm or 127mm spacing?
Number of links: How many weights need connecting?
Problem location: Is the fault actually at the bottom of the blind, or is it part of the headrail/control system?
Taking a minute to check these points should make identifying the correct replacement parts much easier.
Need Replacement Vertical Blind Weights or Chains?
At Blind Parts Hub, we stock replacement vertical blind weights and bottom chains for common 89mm and 127mm vertical blinds, including both traditional chained and chainless weight options.
For other faults, visit our Vertical Blind Repairs & Guides section to help identify the problem before replacing parts.
Conclusion
Replacing vertical blind weights and bottom chains is one of the simplest ways to repair an untidy or damaged vertical blind.
Start by measuring the width of your slats and identifying whether you have a traditional chained or chainless system.
For a chained blind, make sure both the weights and bottom chain match the slat width.
With the correct replacement parts, there's usually no reason to replace an otherwise perfectly serviceable vertical blind simply because a few weights or chain clips have become damaged.
If your chain links have become brittle and broken and need replacing, it may be worth checking your vertical blind hangers while your at it.
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