Cupped Cladding

[djb7]

Left boards stacked flat over Christmas and half of them are now cupped.
I've restacked them in a criss cross fashion bow side up hoping they'll straighten themselves out, will this work or are they unuseable ?.

 

[Deluks]

Are they in a particularly warm room? Are they to be used inside or outdoors?
Wet them, stack them spaced apart with battens in between. Sheet of ply on top and a weight on top of that. Few bags of sand or concrete blocks etc.
Cross fingers. (or touch wood )

 

[djb7]

They're for indoors Deluks, instructions advised to leave for a minimum of 72 hours before fixing, ok i've left them a lot longer than that, about 2 weeks lol, but i'm wondering if i should have fixed them straight away because they were ok when i bought them.
room is just normal temperature, not hot. so it's a gamble then ? just wonder if i'm wasting time, any idea how long it'll take if they are going to straighten out ?

 

[big-all]

how much have they cupped ??
have you got a picture ?
i assume its 88x9mm txg "V" groove pine
i personally think you may get somewhere between 10 and 25% success
how many have cupped ??

 

[djb7]

It's about 5mm out, doesn't sound a lot but they won't pull into place without cracking down the middle.
Managed to get a couple on that weren't quite so bad but you can still feel the cup in the middle.
I've got 45 1metre lengths like this, they were 3mtrs but i cut them down to size when i bought them.

Untitled

• djb7
• 10 Jan 2013
• 1

Untitled

• djb7
• 10 Jan 2013
• 1

 

[AronSearle]

Did you buy them as external cladding?

That amount of warp suggest they have dried significantly, and that maybe they were only dried to about 13-19% moisture content (external use), instead of around 9-13% for internal use.

 

[djb7]

No, it's listed as interior cladding, this is the stuff http://www.wickes.co.uk/invt/121324
I'd take it back but i bought it well before Christmas and also it's been cut down, (before it cupped)can't realy walk in with 45 metre pieces lol........can i ???

 

[big-all]

you could try say 3 grooves in the back around 60% depth in the worst bits and 2 in the not so bad bits
i assume you are blind nailing in the tongue??

 

[rjm2k]

No, it's listed as interior cladding, this is the stuff http://www.wickes.co.uk/invt/121324
I'd take it back but i bought it well before Christmas and also it's been cut down, (before it cupped)can't realy walk in with 45 metre pieces lol........can i ???

Email their customer services and see what they say re a refund

http://www.wickes.co.uk/pcat/emailforms/

 

[^woody^]

They have dried too quickly on one side. It's either the cut of the plank, or how they were stored

Damp them and the re-stack. Or put them outside, but under cover for a few days, and then bring them back in, but don't put them in a really dry or hot place

 

[djb7]

Thanks for the tips everybody, i phoned the store and they thought it was bizarre that so many had cupped but they have agreed to replace them.

I'll make sure they're perfect before purchase as i did with these, but the question is how do i prevent this happening again ? should i fix straight away before they have chance to cup ??

 

[big-all]

it will be the way they are made and stored

i have used several thousand metres off 9mm t&g at present i have around 60m from my local wood yard and the rate off cupping more than 1-2 mm is zero in the 60 or so
i have it in 2 areas in the house stored and the shed where it goes from around 4 degrees for several days to 30 degrees when i fire up the wood burner and the cupping is minimal
yes i have had the odd plank that cups more than 3 or 4mm but your talking maybe 1 or 2 percent so when you look at the way its stored and for up to 8 weeks in long plank lengths and many months for long offcuts as i hate waste

the moral is buy it from a wood yard

 

[joinerjohn]

The sort of cladding that Wickes and the other sheds sell, is usually made of timber that's fast grown (so has a very open grain structure) They generally sell crap timber products at the best of times.

 

[AronSearle]

? should i fix straight away before they have chance to cup ??

Hmm.

I would agree with others, buy from somewhere better, but...

If you had a moisture meter it would really help, I would say fix them straight away, double nails on the board width.

I'd almost be tempted to say fit them tight, so that when they shrink they don't end up disengaging at the tongue, but that makes the assumption that they are to wet.

I didn't appreciate that they are only 8mm, makes them very prone to cupping if the moisture content isn't just right.

 

[Harbourwoodwork]

I think J J has got to the red meat of this,I think also the the width to thickness ratio is pushing at the bouneries for this type of timber, For the fixing I would glue them on with PVA and dovetail nail them, I know this goes against the technology of boarding but because the wood is so thin and pithy there will very little nail holdingf ability, I would just hope for the best because when the central heating gets hold of it it's going to go toasty so fix then leave it to settel in before painting