We recently spoke to a builder who had been buying Correx from the same supplier for around 10 years. They were paying approximately £2.80 per sheet, and we offered them comparable Correx at £1.80 per sheet, including delivery.
Their response surprised us. They told us it wasn't worth their while changing supplier.
At first, we could almost understand the reaction. It's £1 a sheet. Builders have jobs to finish, people to manage, materials to order and customers to keep happy. Nobody wants another task on their list just to save a pound.
Then we found out they were buying around 500 sheets a month. Suddenly this wasn't really a £1 decision anymore. It was a £500-a-month decision, or £6,000 a year, on one relatively ordinary building supply.
That got us thinking. How many builders and contractors are paying more than they need to for everyday supplies, simply because nobody has looked at the price for years?
How do I know if I'm paying too much for building supplies?
The difficulty with consumable building supplies is that the individual numbers often don't look important enough to worry about. A pound extra for a sheet of Correx or a few pounds extra for a roll of floor protection can easily disappear amongst the much bigger costs of running a building project.
Volume changes the calculation. In this particular case, 500 sheets at £2.80 costs £1,400. At £1.80, the same monthly quantity costs £900. The difference is £500 every month and £6,000 over a year.
We've seen how wide the differences can be when we've looked at the wider market too. In our 2026 UK Correx price comparison, we compared published prices for standard 2400 × 1200 × 2mm Correx and found a surprisingly wide range.
So the useful question isn't necessarily, "Can I save £1 on this?" It's "What does that £1 become at the volume my business actually buys?"
Why do builders stay with more expensive suppliers?
Our main hypothesis is very simple: habit.
If you've bought Correx from the same supplier for 10 years, you're probably not making a fresh purchasing decision every time you order it. You know who to call, your account already exists, the materials arrive and everyone gets on with the job. Over time, the supplier stops being a choice and simply becomes part of how the business operates.
There can be plenty of good reasons for staying loyal. You might know the person at the merchant. You might get useful credit terms. Perhaps you order several products together. Delivery might be dependable. You might even enjoy the excuse to pop into the merchant and have a chat.
All of those things have value. The important question is how much value.
In the example above, the convenience of continuing to do what the business had always done was costing approximately £500 a month. Perhaps the existing supplier provides £500 a month of additional value. If they do, that's a perfectly sensible purchasing decision. But if the real explanation is simply "that's where we've always bought it," then habit has quietly become an expense.
Ease versus competitiveness
This is where we think things get particularly interesting for larger contractors.
The person ordering the materials is usually trying to accomplish one thing: get the materials ordered. They have plenty of other things to do, so a familiar supplier who reliably gets the job done is attractive. Changing something that already works creates another task.
The owner has a different perspective. The owner sees £500 leaving the business every month.
That doesn't mean the person placing the orders is doing anything wrong. It means that ordering efficiently and buying competitively are two different responsibilities. A company can have an extremely efficient purchasing process that repeatedly purchases something at an uncompetitive price.
Someone therefore needs to own the second question. Every so often, somebody needs to ask whether the prices the business has become accustomed to are still good prices.
Would the owner make the same decision?
This is perhaps the simplest test.
Imagine the extra £500 wasn't coming from a company account. Imagine someone asked you personally to pay £500 every month so you didn't have to try ordering Correx from somewhere else.
Would you?
You might. Perhaps your existing supplier has rescued you repeatedly when you've needed materials urgently, gives you valuable credit or provides some other benefit you couldn't easily replace. The cheapest supplier is certainly not always the best supplier.
But you'd probably want to know what you're getting for your £500.
That's the part we think gets lost when relatively small unit prices become routine company expenses. Nobody actively decides to spend £6,000 more. The business simply carries on placing the same order.
Small differences become big numbers
Correx isn't unique in this respect. The same thing can happen with all the boring consumables that building companies purchase repeatedly.
We found exactly this when we compared the price of different cardboard floor protection products. Looking at the cost per square metre rather than simply the price of the roll revealed large differences between products and suppliers.
There can be legitimate reasons for those differences. One floor protection product may be heavier, more durable or designed for a different application. Paying more for something you actually need isn't overpaying.
The problem is paying for specifications you don't need, or paying substantially more for the protection you do need, simply because nobody has revisited the purchasing decision.
The same logic can be applied to Correx, cardboard protection, tapes, films and other high-volume consumables. A saving that looks insignificant on one unit can become very significant when multiplied across a year.
How often should I compare building supply prices?
We don't think tradespeople should spend their working lives shopping around.
Your time is valuable. Saving 10p on something you buy twice a year isn't a particularly productive use of it. The answer isn't to turn every order into a procurement exercise.
A much easier approach is to periodically take your invoices and identify the consumables you're buying in meaningful quantities. Look at what you're using, what you're paying per unit and what that purchasing decision costs you over a full year. Then check whether the market has moved.
The important part is to annualise the difference. Don't tell the owner that another supplier is £1 cheaper. Tell them that the business could potentially be spending £6,000 less each year.
That tends to make the purchasing decision considerably more interesting.
Price still isn't everything
Of course, cheaper doesn't automatically mean better value. A cheap product that doesn't do the job is expensive. Materials arriving a day late can cost considerably more than the saving on the invoice. Quality, availability, delivery and service all matter.
That is why the interesting part of our builder story isn't simply that someone was paying £2.80 when we could offer £1.80 including delivery. It's that the difference was large enough to ask what additional value the extra £500 every month was buying.
If the answer is better quality, valuable service or some other meaningful commercial advantage, great. If the answer is habit, perhaps it's time to check the invoice.
Think like the owner
There is a simple lesson we'd take from all of this. Don't obsess about pennies, but don't ignore thousands.
Take the products your business buys repeatedly and occasionally look at them with fresh eyes. Check the price of your Correx. Check your protective cardboard. Check your tapes and films. Multiply any meaningful difference by what you actually use over 12 months.
And if you've finished all that serious financial analysis and still have an inexplicable desire to think about Correx, we've also calculated how much Correx you'd need to protect Brighton Beach. Because apparently these are the sorts of important questions we think about.
The point isn't that you should always change supplier. It's that "we've always bought it there" shouldn't be the end of the calculation.
If a five-minute price check can potentially put thousands of pounds back into the business each year, that's not shopping around.
That's thinking like an owner.
Want to think about it another way?
Watch how Correx Privateer talks about this on YouTube: https://youtube.com/shorts/gpDH0XKd7cU