Timber decking - manufacturing fault or expected?


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11 Jun 2020
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Hi all - hopefully someone in the know can clarify this for me.

Just to make clear up front - with hindsight I know I should have probably bought better quality decking boards. But I've got them now and can't really afford to replace them all just yet so I will have to make do for the moment.

I'm currently building my decking which is my first big woodworking project. I'm only entry/intermediate level at woodworking, but I'm pretty happy the overall frame is built well, all the joists are placed correctly and level, and that there's a small drop built in for drainage. My laser level says it is all good.

I bought decking from Wickes about 3 weeks ago advertised as 3600mm x 140mm x 28mm. Wickes advertise it as "slow-grown premium European Pine". It sat around for about 2 weeks in varying hot/cold/wet conditions before I finally laid it last weekend. All seemed OK until I realised I needed another 10 boards to finish the job so I paid someone to go and pick them up in a van so I could fit the remaining 10 boards the same weekend.

It wasn't until I laid the remaining boards and walked around that I realised there was a 2mm drop in thickness between the first batch and the newer batch. The original batch measured exactly 28mm, but the boards I purchased and fit on the day only measured 26mm thick.

The "newer" boards have been fitted for nearly a week now, have experienced hot/cold/wet conditions but they are still 26mm thick, and there's still this annoying drop between the "old" and the "new" boards:

decking ridge.jpg

To add further confusion to the mix, after yesterdays/todays rainfall, some of the original "older" boards seemed to have crept up to 29mm and even 30mm thick in some places. The newer boards are still holding at 26mm which is exacerbating this issue as the drop can be up to 4mm in places...

My initial thought was this is just a waiting game and that I should expect this issue to resolve itself as the newer boards swell up to 28mm. But my doubt is due to the fact that the decking boards seem to be manufactured differently. They have different labels which makes me think they have probably come from different manufacturers?

decking manuf.jpg

They also have different cuts, the newer boards have sharp edges, where as the original boards have a rounder edge.

decking cuts.jpg

Any advice on what to expect, or possible solutions would be much appreciated!




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They look like they are from different batches, if not manufacturers. That’s not unexpected from a large stockist. That said, I would certainly be asking for them to replace (at their cost) the ten boards for thicker ones at 28mm.

If they won’t, or you can’t wait, then you could take up the 10 boards and pack them out, if you’ve got a way to make shims. Or take up the rest of the boards and plane a couple of mil off the bottom (not ideal). An interim measure would be to gradually reduce the depth of the boards in the middle (pack out, or plane down a few boards at the join) to make it less noticeable.

I’d definitely start by putting it back on their toes though.
I doubt they'll take them back if they have been cut and fixed.
use plastic shims to lift them.
From the photos, the product codes are different in the last 3 digits, so likely different suppliers. I got some Wickes decking a few weeks back when they were about the only people delivering and it came from a branch a long way away, not the local one so they might have regional or area distribution from various Mills.

My first step would be to ask them to replace the 10, then if no response raise a complaint, then I would go with plastic shims but it will never quite match. You might get away with just lifting the lower of the boards at the 'step' and putting shims under one edge. As they mellow any visual differences will become less obvious.

Keep one or two of those stapled on labels to prove your point.
It does happen. I replaced all the skirtings in a bungalow and half way through I scribed one that didn't fit. I thought my cutting must have been adrift, but I picked up an offcut and tried it - it was fine. 127mm skirting, and the ogee mouldings were 10mm different in height from one board to another. I got away with it as most of the doorways were of one side of a long hallway and I managed to keep them seperate. The timber merchant offered to replace the lot though, as he didn't know which were the newest.
There is a place down the road from me that does timber auctions. There are always big packs of flooring, architrave, skirting etc among it. I know a few people who have bought packs of T&G floorboards only to find out that all the pieces don't fit together #-o. It's all rejects and mixed batches but people don't realise, and like a lot of auctions people get carried away and pay over the odds for it.
I clad a shed . Started pre lockdown . Had to order 10 more lengths from Woodyard recently . Same profile etc . They arrived and there was a 5mm difference in the facing dim. Different batch same supplier .