# Waterproof mdf panels???



## Deej (22 Dec 2012)

Had to repair a door the other day, it had been wrenched off its hinges. as i was refitting it i noticed within the window frame next to the door there was a raised panel made from mdf.
it was glossed in with the rest of the window frames which were all made in meranti, where the paint had started to flake on the real wood and the timber had twisted noticeably, the mdf panels were in near perfect condition.
this was in a factory made door/window fitted about 5 years ago. not been painted since.

It would be so easy to use mdf panels, has anyone ever used them outside?

How can you stop them from laminating?

Thanks, Dan


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## jasonB (22 Dec 2012)

You can buy exterior grade MDF, usually has a grey core.

J


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## eribaMotters (22 Dec 2012)

My local timber merchant has Moisture Resistant [MR} mdf that usually has a green core. I have used this for exterior door panels including the T&G effect garage doors I fitted to the front of my house 18 years ago. When I fitted them I ensured the edges were well covered in glue I painted the panels up well once fitted. I have had no problems. The boards cost a few pounds more than standard mdf and they sometimes have to order it in, but this is now the only mdf I buy. It is denser and takes a machined detail better. Off cuts left in the workshop are still fresh a year later.
Fully waterproof mdf, usually fully green, is also available at a far higher cost.

Colin


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## doctor Bob (22 Dec 2012)

eribaMotters":2ljshvd9 said:


> Fully waterproof mdf, usually fully green, is also available at a far higher cost.
> 
> Colin



I disagree with that, green whether it is fully green or just central means moisture resistant, medite has a green core chinese stuff tends to be all green. As Jason above mentions exterior quality is grey usually (medite certainly is)


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## chuggy (22 Dec 2012)

The green colouring is a dye and it indicates that the board is Moisture Resistant. It may show as a thin line or over the whole thickness depending upon the manufacturer.

However, because the green colour can show through finishes MR board is also produced without any colouring at all.

The dye does not, in itself, contribute to the board's moisture resistance.

Moisture Resistant does not mean Moisture Proof.

If MR board becomes wet it will swell and not go back to it's original size on drying, but it will retain it's rigidity. 


Hope this helps.


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## jasonB (22 Dec 2012)

Yes as bob and colin say green core or solid green is MR (Caber is green all the way through) You also find that some makers colour the whole board in the thinner sizes but just the core when it gets over 18mm.

Grey core is Exterior though still needs to be painted

Red/pink core is Fire resistant

If MR gets wet it can well almost 70%


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## Chrispy (22 Dec 2012)

If you think exterior MDF is expensive then try the "new one" TRICOYA it comes with a 50 year live expectancy when painted etc.


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## custard (22 Dec 2012)

Chrispy":ym81zqrd said:


> If you think exterior MDF is expensive then try the "new one" TRICOYA it comes with a 50 year live expectancy when painted etc.



I think Brighton's seafront benches were built with Tricoya MDF. 

It's MDF Jim, but not as we know it.


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## The Wood Butcher (22 Dec 2012)

Tricoya is amazing stuff, the wood pulp is treated with acetic acid and then can't rot. 25 year life expectancy if in contact with the ground, 50 years if off the ground. And all because they washed the fibres in vinegar...

Not cheap, around £100 a sheet, but have you priced marine ply recently?


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## Wornoutengine (9 Apr 2016)

I wish to construct an outdoor slide for my 2year old granddaughter. Would waterproof mdf be suitable for the slide part?


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## wolfey (9 Apr 2016)

For no real reason I would have said no!! but just looked up on the wall in the office and there is the Medite Tricoya broacher hanging up and has a picture of a kids outdoor play centre slide on the front cover!!! So YES!! LOL


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## Phil Pascoe (9 Apr 2016)

It probably had a metal "slide".


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